Christopher Isbell

Intro:

Christopher E. Isbell joined the USGS in 1977. In this interview he was asked about cartographic production techniques applied during analog and early digital eras, and the evolution and application of these and other related techniques as applied to numerous scientific and cartographic projects from early years (1970’s) through more recent times (late 2010’s). In utilizing direct work experience and training, along with an education and degree in engineering, he led or participated in various cartographic, technical, and scientific projects and endeavors. Among others, Isbell participated in the production of Viking-era Mars maps, Voyager-era outer Solar System satellite maps, and Clementine multi-band lunar maps. He was also responsible for the development of Planetary cartographic and data standards, and the production, archive, and distribution of multiple USGS and NASA products, both hardcopy and digital, including many within the Planetary Data System.

Hargitai:

What is the name of the profession you identify as?

Isbell:

I identify in my career as a cartographer. As a professional cartographer. And sort of related to that and obviously was mostly in my work here at USGS. And in addition, during my employment, I went to school, I went to engineering school and received a bachelor of science degree in civil engineering. So professionally, cartography, but then everything associated with cartography in the planetary program, and in some aspects of the engineering studies, I consider that sort of related and helpful in my career as a cartographer.

Hargitai:

Could you elaborate this division between engineering and science? What is the dividing line between these two?

Isbell:

Okay, yes, I guess my interpretation of that language would be, you know, in the traditional sense, I look at engineering as sort of the classic engineering of civil engineering or electrical or mechanical engineering. And then, I think in the vernacular of how we use the term "engineering" here I think would be what I might call the technology side of things, a technical side versus the research side. So I think at least sometimes when we use the term "engineering" we think of the technical aspects of programming or technical drafting or things like that in the engineering side, versus the scientific research side. And at the same time, for those people involved in planetary missions, maybe from the ground floor, there's an engineering aspect to design of the instrument and so on. So that's another context of engineering.

Hargitai:

So could you give me an outline of your career here? 

Isbell:

I started out , just fresh out of high school, I started at USGS right the month after I graduated high school. So in that element, I was on a student appointment. And throughout the next several years, like a lot of people who start out in the USGS, I went through a series of different technical positions, like a cartographic technician or a geologic field assistant or those kinds of entry-level technology positions.

Hargitai:

But your first tasks were terrestrial ones?

Isbell:

Well actually planetary mapping directly. Yeah, once in a while, we would work on Earth projects, but primarily planetary throughout the solar system. And so that first phase was sort of producing hand mosaics, producing hand drawings, putting together hand-produced products would be the first phase, and then as that progressed, I got a little bit in the digital side where we would do digitization of map products. And then as I progressed here at USGS, began to work on a little more advanced stuff, got into a little bit of computer programing in parallel with my technical work. And as time progressed, I recognized it would be helpful for the institution and myself to maybe pursue an actual degree. And that's when I discerned whether to go more planetary side or perhaps something that's relevant but a little more broad in case I went somewhere else in my career. So kind of mid-career, I pursued, or early in my career, I pursued an engineering degree. And that involved a lot of related subjects like physics as well as cartography and surveying in the civil engineering side. So that was sort of helpful in the context of the type of work we did. Continuing on with the things I did throughout my career, as time went on, like a lot of people, you get involved in a lot of different things. So one part that evolved out of planetary mapping, I got a little bit involved in archive and distribution. Where we, you know, as technology advanced, we would research and use developing products to archive and distribute our products. Going from local storage on local disk drives to portable disk drives... of course, originally on 9-track tapes but then going to more local storage, but then as the technology expanded, more online storage and then distributed storage, and then even online, in the distributed sense, there was quite a nice phase of really applied production of CD-ROM and DVD archive, where that became a very popular and usable media where you could store data online but also distribute the product on CD or DVD to customers. And for quite a while, that was a few years, maybe five to eight years, was a big part of my work where I ran a CD and DVD lab where people would request products to be archived on CD or DVD. We had an in-house lab to do that. But also we shipped those out to DVD replication facilities where they would mass-produce them as well. And those got distributed to customers and to Library of Congress, other archive facilities like that. And then later on in my career, I would say I continued in the mapping field, working on most planets in different aspects of planetary mapping early on, so analogue or hand products, and then as things involved in the digital side. And then another significant part of my work would be in the archive standards and cartographic standards where we utilized the Planetary Data System to design and formulate our products to comply with that data system requirements. And so the last part of my career was pretty heavily in the PDS realm, Planetary Data System distribution, and then also as you know, our facility depends a lot on soft money funding, where we write proposals to NASA. So I was involved on the technical side or the engineering side of helping put together a large package proposal that had a significant funding element here in astrogeology. So I was also involved in helping, sometimes writing my own proposals, but primarily helping to gather and formulate a full proposal package that we submitted to NASA to get part of, a pretty good part of our funding here in astrogeology. That's a pretty quick summary, but that sort of covers the basic outline. 

Hargitai:

So going back to your original outline, let's start with hard copies.

Figure 1. Viking hand mosaic, hard copy, USGS manuscript. Photo credit: Henrik Hargitai

Isbell:

Early on, in the 70s and early 80s, the products that we would use to produce a hand mosaic, they were stored in a...there's a lot that happened before this, but ultimately, they were stored as individual frames on hard copy prints and negative film, and those were stored in the RPIF facility in a library form. The negative would be, the original that was made from the spacecraft product, from the instrument product, would be a negative film. But most of them on these missions were produced at JPL, at Jet Propulsion Lab. And we as a facility would receive those negatives along with the positives that were contact prints from those negatives. And so we had a full library of accessible film that was produced by another agency. And then when you were assigned a mapping project, you might be assigned a quadrangle or a section of a planetary body, and you would use either hard material folders or do come computer searches to find the products that you need for your hand mosaic. And so you'd go to the library and pull all those prints, mainly. You would pull the prints and you wouldn’t use those prints, but you'd pull those to visually see what you're looking at. And you would pull the related negative. You would gather all those negatives for your mapping project. And then we would take those negatives to the on-site photo lab, and they would make prints of those negatives at a scale that you requested for your mapping project. And then you would get hard copies of those from the local photo lab here on-site. 

Hargitai:

So the first stage is just the scaling and no projecting or no rudimentary...or any other kind of correction?

Isbell:

That's a great question. That is correct. And these products came in a form of what would be considered engineering data records. The standard engineering data record not projected into any map projection at this point. And so they would be raw products in that sense. And the scaling would be done according to whatever scale you were mapping at by hand. There are times whenever you would have to reproject these products. And they would happen more when we get into the digital side. But this first element of producing hand mosaics, these first products that we would get prints from were in their raw form, and then they would scale them in a camera in the photo lab to appropriate scale. And then those hard copy products, we would take those and put adhesive material on the back of them that you would use to adhere them to a base as you put them together to form your map. Now, in that process, you would also produce overlays that would be like a graticule showing the latitude, longitude, and also this overlay might have control points on them. Control point markers for features on the prints, so that you could match the control, match the latitude/longitude, and simultaneously match the images to themselves. So you're sort of simultaneously putting together a hand mosaic where you're matching the images but you're also matching the control points so you're sort of doing a hand iteration across this map to form a hand mosaic.

Hargitai:

So there was one person who makes the mosaic. Was there a group who made...there was a photo lab that made the photos. There was another group that made the overlays with the create and the control points from perhaps the RAND corporation books?

Isbell:

So yes to both of those. So we would produce the overlays here, but we would use RAND corporation material to identify a control point ID with their number and name, to what feature was on the print. So we'd pull the RAND corporation manual publication and we would take our print and look carefully to match the control point with that crater or that part of a canyon or that peak of a mountain of a control point. So I would have to identify the control point on the print.

Hargitai:

And who put the control points into the grid?

Isbell:

Okay so there are two ways that that was doing locally. Before we had digital plotters...before we had mechanical plotters, there was a drafting section that would produce grids with control points on them. I primarily used plotter material, a mechanical plotter that would plot out the grids, plot out the control points on a plot, on a mylar film that you could see through, were these control points, and graticules would be on this overlay. And as you're laying your mosaic together, you would use this overlay to, once you've identified the control points on the print, you would use the overlay to help have it conform to the control points as well.

Hargitai:

So it was several layers that the overlay, that the control points was the uppermost layer and they moved the photos underneath that.

Isbell:

That's correct. So again, we're covering a lot of good material, but there are so many details in-between. So let me start with what I would call a mylar sheet. Just a plain mylar sheet, it's sort of a translucent plastic material that we bought tons of rolls of those as we worked on this. And that would be your base. And then if, whatever overlays you were using, typically a grid, a graticule, a lat/long grid. And typically on that same overlay would be a plot of the control points. So you would register those two before you even start your mosaic, you would register those control points with your grid and that would be a manual process where you had control points for the lat/long corners. So you would line up everything and you would punch those two materials and you would put tabs on them to register them together. There would be a physical tab with a nice, clean punch in the four corners where you would have an overlay registered to your base. And then that would be your stationary material and as you would peel back the layer, you would start laying out your mosaic, and lay your layer back over. You would manually move your material to register to the control points.

Hargitai:

Did that include the (inaudible) photograph?

Isbell:

Yeah there was a process there as well, so keep in mind at the same time that you're wanting to comply with the control points, you're also registering the prints together. And so you want to match this print with this print while you're still matching the control points. So suppose you have an array of images that are 12 images long, where you would sort of iterate your way back and forth to where you would be complying with the control while trying to register the images together. And of course like any product, it's not going to perfectly match because it's not fully— it's a semi-control, what they call a semi-controlled mosaic rather than a fully-controlled mosaic. So you would do the best you can as a cartographer and mapper to comply with the control while you're registering the image to each other. And it would be an iterative process back and forth, working up and down a mosaic strip with various sources to register both the images and the control. Now, the part about gluing them down or taping them down is, yes, so there is a process where you would take your print and we would use what we called the double sticky, a two-sided adhesive, so you'd peel one side off of the adhesive and put it on your print, and you'd leave the other side with the peel left on, so it's not sticky, and then once that's on there, you would take a knife and cut out your image on the image edges, because these image—as you may have seen in the prints, they have collar material with all the telemetry in them about latitude and longitude and a date stamp and so on. So you would literally cut out your prints to get rid of the collar material. Now you have a print that is ready to use, but it's ready to peel off so you could stick it down. So the process is you would get all of your material ready with this two-sided adhesive on it with still the bottom side protected with what's not sticky yet, and as you'd lay this out, you would take a piece of tape and tape the edge of this film, and as you're working and matching to one another to images, you would when you're satisfied with that, next image, you would take this one as well. And so you're taping this one as you go, and like this would be taped, and then you would match this, the next one in the series, and tape it down. So really you would have a series of prints, sometimes tens to 50s to 100 prints where you would be able to adjust them and look at them as you go with one edge taped down. 

Hargitai:

This was— just a few minutes ago, I found this...

Isbell:

Let me see. Okay this is very good. Okay so this would be a low-resolution mosaic of Mars. And I can see, oh this is very good. I'm now curious who did this. So you can see that, and this is not quite the process I was describing, even though it's similar. What someone did here is they put some adhesive on the corners and as they were working this material, they were able to glue down the corner, and you can still flip and see. This is a hand mosaic of Mars and it's using a similar process that I was describing. Let's see, this would have an adhesive material on the back that has yet to have been peeled off, to expose the adhesive part of it. And there would typically be a piece of tape holding each of these, and then that allows you to remove the tape and adjust it a little bit as you formulate your mosaic across an array of pictures. And then with that piece of tape, you could even flip all this over and fold it over, fold it back, but once you're satisfied with your location of your mosaic, you would start on one end of the mosaic, in this case on this end, and you would peel off the adhesive material and then adhere it down to the base. And then you would take the next one that wouldn't interfere with the others, and peel off the protective layer and expose the adhesive and then you stick this down, and you'd work your way across the mosaic until this is all—instead of all of this being loose, your final product, everything would be adhered to the base. Honestly, this one is probably just an image-to-image match. 

Hargitai:

There are many duplications of the features.

Isbell:

That's correct, and until you make a control mosaic, you won't really be able to satisfy this duplication. And this gets into another point that I'm sure we'll discuss, is of why you might see peculiar cuts between images on other mosaics.

Hargitai:

Who is the target user of a semi-controlled mosaic? And how is it technically produced that it's going to be a one-sheet photograph or photographs?

Isbell:

Yeah so again, we are talking about hand mosaics. So it's an interesting progression of how things are made. So in the hand mosaic mode, yes, I think in a semi-controlled map, once this becomes a final base, this is taken to the photo lab to make one contact print of this. And distributed to whoever, whatever entity is going to use it next for their research. Now sometimes, it's just an internal product that's not published more widely, but sometimes, it would be published as a USGS or other map for someone to officially use as a published map. Now the semi-controlled ones weren't typically—I mean, they were published, but the early on use of these in a semi-controlled environment would be pretty much preliminary research, preliminary geology, that would match this form. And as things advanced for controlled and more intricate digital maps, the same process for someone doing a more detailed geologic map or other scientific map would, this same type of source material as we advanced to the higher controlled products, I think, had the same customers depending on if they were doing an early research or a more detailed research. 

Hargitai:

How was it possible during the manual or hard copy era to create a controlled map using only photographic technology, how can you get rid of the duplications of the future?

Isbell:

Yeah so I guess at that phase, you technically can't. Except for a visual aesthetic. If you imagine two images adjacent to each other that have done the best we can in controlling them to each other, but you still get a duplicate product. So you could imagine, just for aesthetics, recognizing that this is not cartographically accurate still, you could imagine for aesthetics, you could take your blade and cut this corner and you no longer have a duplicate. Of this prominent feature. It's still uncontrolled, it still will have technically duplication but to your eye it won't be as obvious. So for the sake of an aesthetic map, we might—adjacent image—we might remove this duplicate visually, so that you get a more aesthetic map. Recognizing that it's not accurate, but it's aesthetically more useful to the eye.

Hargitai:

How did technology enable the next step in making more controlled? 

Isbell:

So the next phase in doing this would be taking these raw products and running them through a computer process to correct them, not yet map projection, but to correct them to the proper form of the planet. And so what I mean by that is the terminology is coming to me as we're talking, but in this case, you would start with a raw engineering data record that has no correction or no geometric correction yet. But this product, based on the telemetry that comes with it, you can even before you get to a map projection, you're doing an ortho photo projection, that's the term I’m looking for. Where this image might have been taken at a particular emission angle and phase angle, where knowing those parameters and telemetry that came with the product, you can run it through a computer mapping program like we do currently more directly with GIS and stuff, to where you've orthographically corrected that image to better match the body that it was mapped.

Hargitai:

So it wasn't a practice at that time, for example, that if you know how you should rotate in 3D the photo that you actually rotated the photo paper, for example?

Isbell:

Right, we did not do that, no. Now again, this is early on semi-uncontrolled products for this early on stuff. That's right, we didn't do that in a manual sense.

Hargitai:

So going to the next phase, you described, flatbed or drum plotters, or I don't even know what that is...?

Isbell:

Okay. I wish I had a picture of one. So a plotter would be, imagine this flat table here that is designed as a plotter that has a pen head on it. That would draw lines on a plotter. So this table, a calibrated table, with a mechanical arm that has X and Y dimension in order to do plotting. And so we used software that we developed here to produce graticules and control points that would draw latitude/longitude grids, control point grids, topographic lines, and these would be physically run, you know, recorded to a tape and you'd take the tape to the plotter and the plotter would follow the commands on the tape to draw out these overlays. 

Hargitai:

So it's a printer that was a pen and did that.

Isbell:

Yes, that's correct. It's pretty much an XY coordinate printer, but it's a plotter that literally uses a pen head and other heads to draw products, yes.

Hargitai:

And what is the drum plotter?

Isbell:

So a drum plotter is just the next, a different aspect or instead of a flatbed plotter, a drum plotter is literally the base material sits on a drum, like a circular drum, to where the drum moves and the pen moves, where you still get the XY coordinate. So you have a drum, let's say a six-inch drum, where the material moves in one dimension, say in the X direction, and that accommodates the X movement, and the pen head that sits on this drum moves in the Y direction, so you get both aspects. 

Hargitai:

Okay. Topic would be the photo lab, and I see that there must be some photo developing place here.

Figure 2. Ramona Bourdeau

Isbell:

Yes. This is great.

Hargitai:

This is from your time or before that?

Isbell:

Yes, now these pictures may have been taken before my time, but I'm very familiar with what you're showing me here. So these are photographs of people working in the photo lab, and you're seeing, I would say, three aspects of photo lab work. In this first picture, by the way, this is Ramona Bourdeau working in a photo lab where, this may be taken in the darkroom, where she has exposed film and she's developing the film in a developer in the darkroom. So she's taking probably exposed film and developing in the chemical development here in the photo lab. Here is an interesting process. This is a development drum. Now, that's probably not the word for it. Rather, a development table or development drum. This is a product where when you have large—when you have to develop something in a very large format, you know, three or four feet across, this drum is the... you take your material that you're developing, like an exposed negative or a contact print. It sort of self-adheres when you put moisture on it. It adheres to this drum. And then you spin this drum at a specific speed, and then it allows you to pour on your developer material, and it spreads.

Hargitai:

It's uniformly?

Isbell:

Uniformly spreads the chemical in order to develop the film. So this is a developer process here as well. It's fascinating. Now, here, we're getting into our large format camera. And so, you know, there's a lot to talk about the large format camera. But basically, this camera was a two-room camera with the lens of the camera in the wall between the two rooms. This is one side of the camera in the photo lab. This large format camera consisted of two rooms with the lens of the camera in the wall between the two rooms. And then the focal plane of the camera was in one room and the subject of your photography would be in the other room, so you would put your subject material on this flat surface here, and then you would put your unexposed film in the other dark room and then you would adjust...this was an adjustable lens where you could adjust the distance and then expose your subject onto the yet-to-be-exposed film. 

Hargitai:

So is this, the size is because you want to make the same, want to run copies of the subject?

Isbell:

So there was a process for making 1:1 where you would just make a contact print, but you could make a 1:1 with this camera. You could do a 1:1, but also really the most common thing would be, you would either scale down or scale up the source to your exposure. You might do an enlargement. 

Hargitai:

That's, why do you want to enlarge it?

Isbell:

You're enlarging it in order to match the desired scale of your output product. So you might have a source image, like we talked about earlier, when you're making this mosaic. You'd have a source product and then you would need to scale it—let's just use an example. You'd need to scale it 3.3 times as big, and so you would adjust your camera in order to make a 3.3x product that you would use in your new mosaic. Now, this was done for large products on a large format camera, but we also had smaller format cameras. There's not an image here. Where you would just do it on a tabletop, and you'd put your negative in the enlarger and you would see it projected onto the film and you would adjust it.

Hargitai:

What was time that this technology was used, from which time until when?

Isbell:

So let's see, I started working here in 1977, and this process was in full use at that time, but it had been in use since the 1960s in the Apollo era and so on. And then—

Hargitai:

Do you remember when it was last used?

Isbell:

Yeah, it's hard to say because it was an evolution. As it was slowly phased out. For sure into the 80s, and even into the 90s, we were still doing some local photo lab use. I think it phased out pretty heavily in the 1990s. I'd have to confirm that, but yeah. 

Hargitai:

The next topic is drafting, the drafting shop. So who were in charge of the drafting or how they learned and what they did.

Isbell:

Sure. Okay so I wasn't personally directly involved in the drafting, but we had a drafting shop here that the primary leads for the drafting shop were Roger Carroll and Jim Vandivier, who was the lead in leading the drafting shop, and there were different people who did different type of drafting. People would use rapidograph ink pens for drafting. They were also very meticulous people who drew grids and other products with scribe, with a scribe, where you would etch a material that you could etch out a line where light can go through it, where light couldn't go through it until you etched out a line.

Hargitai:

These are these red films?

Isbell:

The red and orange film, yes. And so scribe, sometimes they would draw with ink rapidograph pens, sometimes if it was a requirement, it was for a scribe grid, they would etch out these scribes on this orange material and mix the orange and red. There's more that they did than that, but that was primarily the kind of products they produce, is hand-drawn grids and hand-etched, scribed material.

Hargitai:

So basically, the end product that we can see the geologic map, for example where the final version was all done by the draftsman?

Isbell:

That's right. That's right. I mean, the geologists would of course would produce their map, and the draftsmen would take those geologic maps, geologic units, and geologic boundaries, and etch and draw those boundaries and color, use these scribe material in order to be able to make multiple layers in order to produce a color map of their units. So yes, at that time, the drafting process was very much involved after the scientists produced their geologic map in order to draw out the different parts of a geologic map in the drafting shop. This is early on, of course. 

Hargitai:

Airbrush.

Figure 3. Example of an airbrush map, detail, showing the transition of available images from high-sun to low-sun illumination conditions. Map of Rhea, a satellite of Saturn, 1982. USGS map I-1484.

Isbell:

Yeah so, right. So the airbrush process, again, I wish you could talk directly with some of the original air brushers, and I hope you get a chance to talk to others who were involved in the time as well, but the airbrush process was just an amazing process. Before I was involved or worked at USGS, the airbrush technique was developed by people that I know anyway. Jay Inge and Pat Bridges at Lowell, and so this airbrush process used the airbrush mechanism to use the airbrush and the ink to artistically draw the different features.

Hargitai:

How the airbrushers work was integrated into the mapping process?

Isbell:

Yeah so the primary purpose was, once the hand mosaic was produced, the airbrush artist would then take the final product like we see here and put their own overlay over this, their new overlay of a mylar translucent material. And would use the airbrush to visually look at the source product and reproduce that by drawing the features onto this new sheet. Now, you can imagine that as they're airbrushing on this new sheet, they might slip, you know, the process involved slipping a white sheet to hide it while they were drawing so they could see how their airbrush process is reproducing that product so there would be a mylar sheet here, covering this, and they would use the airbrush to draw this feature and as they're drawing it, they would use something to hide what's behind them so they could see how their drawing is going. Does that make sense?

Hargitai:

Mmhmm.

Isbell:

And so this process, it was an amazing process. They would use the airbrush to spray their ink onto the base, or onto their base, and reproduce this whole... produce a whole map. And there's a lot of purposes for this. Two of them that come to mind is, as you can see, any mosaic that is especially uncontrolled at this stage has different sun angles, different craters, and also you have seams between the images, so once the airbrusher was trained to produce this map with a common sun angle. So the brightness and darkness and albedo within a crater is going to look different at this sun angle, at one sun angle versus another sun angle. So the airbrush artist was trained to produce this whole map with a uniform sun angle. And also to get, obviously you'd get rid of the seams between images. So I mean those are only two that come to mind. There's more involved in that process, but the airbrush artist, the final product of an airbrush drawing is a seamless and uniform sun angle. And uniform tone, if that's what the requirement was. Sometimes you'd do a uniform tone map and sometimes they would produce a map that has the albedo variation in it like you see in these images, where you'd have albedo differences that they would reproduce with the airbrush. So you'd have these darker albedo features and lighter albedo features that if that was the requirement for that map, they would do the albedo as well. Or, if the requirement was to produce a uniform shaded relief, they would remove all the albedo and make it a uniform shaded relief airbrush map. Now, another tool, essential tool in the airbrush process, was besides the airbrushing, they also had a motorized eraser. And so this eraser would have a little... different points on it, maybe a fine point or a more subtle point, but this eraser was part—an eraser, a motorized eraser, was a part of the process to formulate a map, because when you spray on your ink, you would then follow up with a motorized eraser to highlight, to remove, to add...where it's too dark, you would remove it to make it lighter. So there was airbrushing and eraser to get the products you need.

Hargitai:

And was it mechanical or chemical for the eraser? Was it just carving out material?

Isbell:

No, it was a motorized mechanical eraser that would just remove the ink. It wouldn't etch out anything in the middle.

Hargitai:

So it would not dissolve the ink?

Isbell:

No that's right, it would remove it, yes. Now, this motorized one was for really continuous use, and of course, the airbrusher had a little small handheld regular eraser, specialized eraser, but not a motorized one, where they would by hand do a little touching up. But an airbrush, an eraser, to produce an airbrush drawing.

Hargitai:

And what was the material they were on? The mylar?

Isbell:

It was a mylar material, yes.

Hargitai:

And that's strong enough for the eraser to survive the generations of use...?

Isbell:

That's correct, and they would have to be careful that you don't, you know, etch too deeply into the mylar, but yes, the mylar was strong. It was a high... in that case, it would be a harder mylar that would be resistant to the eraser, yes.

Hargitai:

Like you described, you used the word "artist." This is like a computer modelling of the surface and illumination, it's a very different skill, and I just can't imagine how long can develop this kind of skill.

Isbell:

It is amazing. It is hard to imagine, but you know, I can't speak for how the original airbrush artist or technician or designer, how all the different aspects of what it took to do that, but like you said, there's training involved in recognizing how to apply that technique to a scientific product along with the artist part of it. Yes, it's impressive. You know, we've already mentioned Jay and Pat. And like Susan, in this list, Susan Justina, originally before that Susan Davis, same person, she was here a pretty good while, a longer time, so she would be one of the primary airbrush... and yeah, I think some of these people were here just a shorter amount of time, and I think there was a phase where we brought in, you know, the group brought in people to learn airbrushing, because you know the original airbrushers were, would eventually retire, so they started training younger airbrush. And of course that was a need, but I think as time evolved, maybe the airbrush requirement sort of phased out as we were able to produce shade of relief maps more digitally, and that requirement for airbrush, at least in the context of planetary mapping, sort of phased out. Maybe there was an anticipation of a higher need. And then as things phased out, they recognized we might not need it for as long term as we might have thought.

Hargitai:

So I collected some terms to describe the materials. It was (crosstalk).

Isbell:

These were just older methods of making a copy of something that wasn't a film copy.

Hargitai:

On paper?

Isbell:

On paper. Yes.

Hargitai:

Black and white?

Isbell:

Usually monochrome single color, not necessarily black. And these are typically, these ozalid were like, they came out blue because of the chemical. And so you would take this map in black and white and run it through an ozalid machine, not a copy machine like a film or a photograph or a photo lab or a camera, but just a chemical process that would make a contact print through a chemical process in an ozalid machine just to make a copy of that in just a crude blue, and it came out blue at the time.

Hargitai:

So was it an in-house...?

Isbell:

In-house machine, yes. And it was typically done for more... quick turn-around. You wouldn't use them as a registration or anything like that, it was just something to make a copy so you could make notes on it or...

Hargitai:

Like a photocopier, just for (inaudible).

Isbell:

Yes, mmhmm.

Hargitai:

And then optronics, negatives...

Isbell:

Oh gosh, wow. Optronics. (laughs) Wow. So okay, once images were able to be digitally stored on a computer, there was a machine that we had that was called an optronics machine. And this optronics machine would be able to produce a negative directly from the digital storage of the image. It was a device that was attached to the computer and it was a drum and it had a lid on it where you could make it dark, so in the darkroom, you would open this drum and you would attach a piece of film to it. In fact, I'm holding one right now. Here it is. This is made on the optronics machine. And this unexposed film would be clipped into this optronics machine and pressed against the drum and held to the drum, and then you would close it into the dark. And then you would take this drum and mount it to the machine that was interfaced with the computer. 

Hargitai:

So moving to early digital, so what kind of softwares were used from when the softwares appeared at all in this process? How and what was the role of the computers? 

Isbell:

Yes so really, since early on, some of the cartographic processes was quite a unique technique. So there wasn't a lot of commercial production of these kind of requirements, yeah, like GIS now. But so what happened here at USGS is the group produced their own cartographic software. So early on would be even developing software that would produce the commands to draw on these flatbed plotters. And then also the USGS developed a very intentional and specific cartographic image processing set of tools. And so early on, these were done to where in a system called PICS, P-I-C-S. Planetary Image Cartography System. And it was basically software developers and scientists involved as well, of course. Where they would develop map projection software and cartographic plotting software and other software to produce cartographic material. And this was an in-house development. And that software was used where you would bring in your—instead of going to the photo lab, producing your map by hand, you could then read in your images off a 9-track tape, run it through our cartographic software, and reproject it, do what you needed to do to produce a new product in the proper, corrected format or map projection format. And then, you would have a digital product that you would then take to your optronics and produce a negative that you could then take to the photo lab to make a print. So that's where the digital process, you could see it seems pretty primitive now, but it was a big jump from making a hand mosaic to be able to in-house locally read in an image, reproject it, make a print, and get a photo lab print... sorry, make a negative and then get a photo lab print that you could still make a hand mosaic, but it would be a more controlled product. And then other people are much more qualified at this, but as time evolved, there were people who designed updated and more sophisticated cartographic software. And that would be, for example, I'm making a big jump. I mentioned PICS, Planetary Image Cartography System. And then the ISIS system is the newer version of that that evolved from different computer platforms to newer platforms and newer operating systems, so the ISIS system which with other software developers and others who were involved in that development could speak better to that, but as a user of that system, the ISIS system, Integrated Software for Images and Spectrometers, that software suite became more advanced and capable in producing planetary cartographic products. And that sort of became the primary product for producing planetary maps. ISIS was used locally of course but distributed to institutions across the world where people use that software to produce scientific products, cartographic and scientific research products. That's a quick summary of going from an early cartographic system to the more developed ISIS system that we use now.

Hargitai:

Good, and do you know if ISIS is used for any terrestrial mapping or it's only planetary?

Isbell:

It is capable to bring in terrestrial products, yes. Certainly, you know, I personally didn't work on a lot of Earth products, but there's you know, there's a decent amount of Earth mapping that was done here, but primarily, terrestrial of other bodies, but we did do other map products when the requirements were there or when there was a proposal to do so using Landsat images and entities like that to produce Earth-based maps. 

Hargitai:

So the next title is data and cartographic standards. What's the difference between the term, what is the cartography standard?

Isbell:

Okay great. So let's see, as planetary mapping evolved...and again, when I say planetary mapping, I think you know I mean sort of the whole spectrum of it, not just geology or not just shaded relief mapping, but the whole process of producing planetary scientific products. And as time evolved, I can see NASA started to recognize that they needed to very much start to develop standards to where as people produced products, they complied with certain standards. So this ultimately ended up in the establishment of the Planetary Data System. Which is a NASA entity, which the USGS was very much involved in. In fact, some of the people like Larry Soderblom and Hugh Kieffer, people like that, were in on the ground floor of giving input to and making sure the planetary data system had the requirements and the standards needed to guide producers of these products to make sure they were done to certain standards. So the Planetary Data System established cartographic standards in one sense, in one element of that, to where there was map projections to find what could be used, mapping series that could be used, these different cartographic entities of a map or a research product, that they would define these standards so that producers would comply to those standards. And in parallel with that, or related to that, there was also data standards produced on how you would store your digital data. In other words, making sure that the data were usable broadly across computer platforms so that someone using a PC and someone using a Linux system, someone using a mainframe VAX, digital VAX system, that the storage of the data was such that the users could use them in their different entities. 

Hargitai:

After this here, you created digital products. So how you moved into this?

Isbell:

Yeah it was probably, in the scheme of things, probably a pretty fast transition from purely analog to purely digital, but in-between, there's quite a few steps. But sort of at the basic level, let's take a digitizer table. Okay so backing up, let's say you have a topographic map that was produced completely analog, not digital, so if topographic contour lines were made in a photogrammetry section by people looking through a 3D model machine and drawing out these topographic lines. And that wasn't necessarily recorded digitally, it was just drawn on a sheet. Okay so now you have a topographic map that is useful visibly, but now you want to convert that topographic contour map into digital form. So you would take this topographic map that was on some type of mylar sheet and you'd put it on a digitizing table that had an array in the table, an electronic array, that you would use a cursor or what we called a mouse, a cursor to move this cursor along the topographic lines and the digitizer table and its interface would digitally record the XY coordinates as you, the horizontal XY coordinates, as you traced a topographic line. And it would record those XY coordinates onto a digital tape. And then that digital tape could be read into the computer to produce a digital form on the computer of those topographic lines. But now, you can use this array of XY coordinates to process this digital topographic map through our cartographic software. First put it in a projection form and then there's other software that would interpolate between the contour lines and fill in the whole image array of contour levels. And now you have a topographic model in the computer that you can treat like any other digital image. And reproject it and produce at different scale and different projections again in the same way you did a digital spacecraft product. So that would be like digitizing a topographic model that originally came in analog form.

Hargitai:

And the other, the scanner?

Isbell:

Yeah so once the individual source products were brought in digitally to a computer, then making a full mosaic instead of a hand mosaic, making a digital mosaic in the computer, obviously there's no more scanning needed. But in the interim, if you made a hand mosaic, and once it was done, you wanted to digitize the final product, so you would take a photographic image of this product and you'd have a negative, then you could put this negative on a digital scanner. In other words, the reverse process of the optronics, because you could put a negative in an optronics machine, and have it digitally scan it in the same way that you would produce it the other way. You would scan this image into the computer and then you would have a digital version of this mosaic. Now, so that would be in smaller format, 8x10 optronics system. Now, if you made a larger format image of a larger map, we didn't have an in-house scanning for that, we would send those off to a large format digital scanner. Where they would do larger format scanning for us, and we would get the digital version back. Now, this is just getting the product into digital form. And now, of course, once that was in digital form, you would use the local in-house software or as time developed, you would use commercial software like GIS software to process that data. 

Hargitai:

And was it, CD technology ever used for primary archiving of planetary original data?

Isbell:

Yes there was quite a period where we intentionally stored original EDR data from the spacecraft on CD and DVD. And those were stored as, technically as an official archive of the data. And then of course the derived products, map projection products, map series, fully mapping, those were also stored on CD and DVD and distributed to the users in those forms. So they were official archive...it's amazing, you won't see any here now, but at one time, all of our shelves were full of CDs and DVDs of all the official data. You could go pull those CDs or DVDs from the shelf and read them into your computer to do some more mapping from those source products.

Hargitai:

I found in a... I've read many monthly reports from the USGS. And in one, I found that during the Voyager 1 encounter, that you, Pat Bridges, Inge, and Rich Tyler worked at JPL during this encounter. So why was it needed to move from here to there?

Isbell:

Great question. Yeah so it's an interesting time period. It's bringing back a lot of memories, Henrik. So as we described the mapping process, the early-on mapping process of sort of doing hand mosaics and airbrushing and producing grids for those overlays, sort of that process before everything was so digital, that mechanism of producing maps was pretty fine-tuned and pretty efficient in the sense of doing it by hand. So the timing from, even though the digital process might have started, the timing of getting everything into the digital form and producing a product was more expanded then. So when Voyager 1 did the encounter of... when Voyager 1 had its encounter with Jupiter, and then later Saturn, but you asked about Jupiter, you know, the interest and the need for sort of real-time map production was always desired, so we sent a crew to JPL to, as the imagery was literally being downloaded from the spacecraft and stored on systems at JPL, they had a mechanism for printing those out, and so we had a team that would apply the same process we did here in a more production form. We applied that process more in a mission encounter real-time sort of needs and quicker turnaround. So we would produce, you know, we would go out there and apply that process to produce uncontrolled mosaics so that scientists could do some initial evaluation, airbrushers could do some initial drawings, right there on-site in the lab at JPL. So we would go and apply our expertise or our practice to produce maps during the encounter. We would make hand mosaics using their print material, but we would produce overlays with grids there at JPL, and sort of in a hasty but adequate way, produce maps real-time so that users could get their initial look at them. Some of them were press release products for the press, but still used by—even those used by scientists to do some initial evaluation, initial analysis. So you know set up shop there for making mosaics and the airbrushers set up shop. We had their airbrush stuff shipped out there and had it all set up for a period during the encounter. As we're talking, I'm sure more will come to mind, but you know besides the scientific part, which of course was the primary part of producing these products and again, the airbrushers drew these maps real-time as well. There was also very much an interest from the press. And the press came on campus there and you know this is not long after Apollo, right? This would be in the late 70s, early 80s. And so that's only seven, eight years since Apollo. There was still that public interest. And an example of that would be like for example in our shop that we set up, for example, Carl Sagan came by. And Carl Sagan just walked around and talked to us and just had an interest in what we were doing, and of course, the people who were not necessarily scientists who were interested in Carl Sagan, he would have some exposure to his audience of seeing what we were doing. And then an author like Ray Bradbury, a science fiction writer at the time, he came into our shop. You know, these people intentionally got passes to come to JPL during the encounter and just kind of came through and they were escorted with officials where they would take an interest and kind of see what we were doing. So I guess I'm expanding your question to besides the scientific and technical needs, there was a cultural interest. You know, there was that cultural element of exposure to the public as well.

Hargitai:

So they made sort of open house for the public to see how mapping is done?

Isbell:

Yeah, now in some sense, yes. Now that was a very much controlled environment where there was no public open house, but with, you know, we all had to have passes and security to get into JPL during these, especially during these encounters. But yes, in a sense, the open house through those entities to the public, yes.

Hargitai:

Was there any single person, a driving force behind the mapping activities, or it was distributed between many experts?

Isbell:

Okay so, again I'm giving you a particular perspective sort of on the technology and engineering side, but we were all integrated— of course the names you mentioned, like Soderblom and Kieffer and Batson and Wu. Let me try to divide it into sort of the research side, as far as scientific research, and then in some sense, the technology or engineering side which I'll mention a few subelements of that. During and after Shoemaker, you know, you have, to me, the obvious primary players, like Soderblom, Hal Masursky, you know, Mike Carr, Gene Schaber, others. Those primary players for sure. And then there are different specialties. And of course, I wasn't in that realm in the sense of research, but we all integrated and worked together. And then the element that I worked more in within the map— you know, when I say mapping, there's a geologic mapping, but when I say mapping, I'm thinking of cartographic mapping. And so Ray Batson, who was the primary pioneer/lead in the cartographic mapping, where we did the hand mosaics and the graticules and so we made all the base maps using planetary products, of course that the scientists then used for their geologic mapping or other mapping. Geomorphology, other scientific research in addition to geologic mapping. So Ray Batson was the primary lead there. And in the photogrammetry section, you know, where topographic models were produced, Sherman Wu was definitely the pioneer in that. And then people like Randy Kirk and Annie Howington, you know, Ray Jordon... people like that, but so Sherman Wu was the primary there. And then those two elements were sort of worked together to produce products that the researchers used. When you always think of the researchers or even the computer technology, but in the drafting shop, Roger Caroll was one of the primary people I mentioned in the drafting shop, Roger Caroll and Jim Vandivier. And within that earlier group mentioned was the airbrush team, that is within the group of Ray Batson, the cartography group. 

Hargitai:

So who trained these workers here?

Isbell:

Yeah so gosh, it's a great question, and you reminded me of some detail. All the training for photo mosaic process, cartography processes, even the drafting shop...even the computer programming. Of course, for software development. You know, most people took courses in that. But since it was so specialized, it was a lot of training in-house too. But again, covering all the topics, the mosaicing process, whether it was hand mosaics or digital, the photogrammetry process of producing topographic maps by hand or more digitally, drafting, map production. During the time of the 70s and 80s and 90s, it was mostly in-house training, although people brought in their education experience as well. But yeah, most of that was specialized enough to be in-house training. Now, people would go and take courses in cartography. I did that. People would take courses in drafting. But the application of those specialties in planetary focus disciplines was very high percentage of in-house training. I was trained by people here and then I trained a lot of people here.

Hargitai:

It's a good way of community building.

Isbell:

It was definitely community-building. 

Hargitai:

Okay, now some projects. Color photo mosaic of the equatorial belt of Mars. So how color blended the map scaling to the picture.

Isbell:

Yeah so that would have been during the Viking era, Viking orbiter. The different campaigns of the Viking project, the primary campaign was monochrome. You know, single imagery of Mars. And then there was a campaign, and someone can speak better, what they call the campaign to take multicolor images of Mars. So we take three color images of Mars. That campaign that produced... that collected data in the three color bands, red, green, blue, that just meant we would now have a project to produce those mosaics in color. And it would basically be making three mosaics of an area, because the red, green, blue weren't necessarily exactly the same footprint, so you'd make a map of the red channel, you'd make a map of the green channel, and you'd make a map of the blue channel, and then this, these three different layers were registered and used to make a color mosaic of Mars. 

Hargitai:

So that was on the wall sometime, but this is not color. This is just an artificially-colored black and white, it seems to me.

Figure 4. Viking photomosaic in disassembled state at USGS Astrogeology. Credit: Henrik Hargitai

Isbell:

So actually—this is actually a three band color of Mars, but it's not true color. It's an exaggerated color. You're not going to see Mars this intensely red. But again, you can see the albedo here and the color variation, but it is an enhanced color.

Hargitai:

You were mentioned, in a project of Saudia Arabia mapping, so how is it connected to planetary?

Isbell:

Oh, well, good memories. I mean it brings back good memories. So, you know, quite often, the expertise that our group and our groups did was, you know, other entities within USGS and on occasion outside would know of our techniques and say, well, hey, maybe we'll use the cartography group to do some mapping for us. The digital mapper in USGS that worked mostly on his stuff was (Pat Chavez), and he had a funded project to produce a mosaic of Saudia Arabia using Landsat imaging. And so Pat Chavez, he didn't have a mapping group, so he contracted us in the cartography group under Ray Batson to produce this map of Saudi Arabia. And Rich Tyler, as you mentioned, Rich Tyler was the person who I worked under when I first started and trained here. So Rich and I, we were on, if you want to call it, assignment at Chavez’s on a part-time basis to produce this map.

So this mosaic, if it's still here. When I left, it was here. You'll see it on the wall in building 3. So you might check if you get a chance before you leave, to see if the Saudi Arabia mosaic is still mounted on the wall in building 3. Okay so this was another technique I hadn't mentioned, Henrik, of how to produce a map. A photo map. It's a derivation of a photo mosaic. It's a little more complex now. I'll tell you what it is, it's called a negative mosaic. So what we did the Saudi Arabia mosaic using negatives instead of hard copy contact prints. Actually negative film, we made this mosaic. So we determined which Landsat imagery was needed and we had those negatives produced and we made a mosaic of Saudi Arabia. Now, some things that come to mind is, when you're doing a hard copy photo mosaic with positive photos, you know, we went through that process so that we could visually see. Well, with the negative mosaic, we had a big light table and we had a single sheet of Saudi Arabia, maybe multiple sections, but let's just say we were working on one section, and you'd have multiple overlays, and of each of those overlays, you would have certain negatives that you could lay out in there. You did the process the same as you would a positive hard copy photo mosaic, but you're using negatives. So what we did was, in this negative mosaic process, instead of cutting out the edges like we did on the hard copy photo mosaic, we would draw the boundary line between the negative. So we could draw the boundary line between the negative, so you would go around this mountain or we would go through this channel to match the negatives as best we could with that single line. There was a mask for each layer. That's exactly right, it was a mask. 

Hargitai:

It's quite complicated. (laughs)

Isbell:

Yeah, it was, and what I remember about that masking process, Henrik, is that one requirement was from this mosaic was to sort of not hide, and I don't mean that in a negative sense of hide, but to eliminate all of the petroleum product plumes that would come off of the refineries. So picture a refinery with all the plumes coming out, and I don't mean to hide them in the negative sense, but to make them aesthetic. To make a nice mosaic. So you might have in this negative this processing plant with the air movement going to the northwest, so you'd have a plume going to the northwest, but on this negative, that has the same processing plant with the air direction going this way, so you'd have the plume going this way.

Hargitai:

The wind changed, right.

Isbell:

So we could draw our line in a way that both of those plumes would not be present. So we would make a nice-looking mosaic that way. Those were the techniques that come to mind. 

Hargitai:

Planetary nomenclature program.

Isbell:

So the planetary nomenclature project or process goes way back to the early days and early on, the person in charge of planetary nomenclature was Mimi Strobel. So she was the USGS representative on the IAU, International Astronomical Union, and under the IAU they had this planetary nomenclature project, and Mimi was the planetary nomenclature representative for USGS, and she would go to all the IAU meetings. And she was involved in the whole approval process and proposal process for naming. And then that was passed on to, when Mimi left, Joel Russel was involved, Joe Russel, and then Jenny Blue and then Tenielle Gaither. Yeah, who I think is still here. 

Hargitai:

Yes.

Isbell:

So she could give you a little history too. 

Hargitai:

Now moving, that's my last block of questions. The more personal questions. So what brought you to the planetary field and not something else?

Isbell:

Okay. 

Hargitai:

What were your early influences in this? 

Isbell:

Okay, thank you. I would say it's interesting that when I look back, and I don't think this any, what I'm about to say isn't necessarily a big influence on why I ended up working in this field, but it's interesting that I had these experiences. When I was in first and second grade, I lived in Houston, and that was the time when they were sending Apollo, you know, Apollo missions, so we, our family, I come from a large family, we were sort of very interested. We lived right there in Houston, and whenever they were sending even the early Apollo launches, we would get in front of our fuzzy TV and watch some of the test flights take off, and I was just a kid, but I was sort of mesmerized by it and so that was sort of always an exposure in my life, and then I remember teasing with my brothers and sisters, it was completely a tease. You know, "I'm going to be the first man on Mars!" Because they talked about the first man on the Moon, right? But anyway, that's just some fun little stuff as a kid. And then later, I moved to this area in Flagstaff around USGS, and like I said, when I graduated high school, they sent some people to the high school and they interviewed me for just a starting out lower level student position here. And so I was hired on as just a lower-level, entry-level student position. So I didn't end up here by pursuing a degree in planetary research or planetary cartography, but I came in with an interest and felt fortunate to even... you know, it wasn't like I pursued it, but people came to the high school and they interviewed me and they hired me here, so I guess in some sense, I was fortunate to just get on board and then that, you know, I learned a lot here and then like I shared, I recognized the need for more education, and I ended up doing... and along the way, I did take some cartography classes and some imaging processing, remote sensing courses, but then I realized I thought it would be beneficial either here directly or elsewhere, if I went elsewhere, to get an engineering degree. So to answer your question, my interests sort of grew up here in a sense as a young adult, and I grew into the cartographic realm of this, and it was a technical interest for me as I went through it. It seemed to fit me. And then when I went to engineering, which included engineering but also physics and chemistry, which was a nice exposure to what we did here too.

Hargitai:

You mentioned being the first man on Mars? So if you would be the first one on Mars, where would you land?

Isbell:

I would like to land right next to Juventae Chasma. I'm not pronouncing it right, but the grand canyon, the big canyon on Mars. And I'd like to look into the canyon on Mars. Or/and, I would like to land next to Olympus Mons to see the largest volcano in the solar system.

Hargitai:

So the Chasma, you would land on top of the wall? 

Isbell:

Yes. On top, on the top edge to look into it. And then maybe next to the volcano to look up at it. Now of course, if you stand on the edge of the Earth's Grand Canyon, you can see all the formation, but if you stand on the edge of the Chasma on Mars—it's so big, you won't get that impression of looking into a canyon.[Edited to add: Actually, for some segments and side canyons of the vast chasma, the canyon view would be quite impressive, especially the nearby edge or rim, as compared to the very distant rim.] It would be vast and far away to the distant rim. Now, I admit, I say that—I just shared that with you because you asked, it wasn't like I expected or even claimed to be qualified to be a person to go to Mars, but—

Hargitai:

Yeah sure.

Isbell:

It was just a fun response to your question there.

Hargitai:

If you would go to a school and you would want to show how good it is to have a career in planetary science, what would you tell the kids?

Isbell:

Okay great, great. Without getting too philosophical or cheesy like my kids call it, I think I would look at it and present it in the same way as society learns new things. Whether it was explorers going to another continent or just a tribe member going up a river to look at another place to learn about something. I would look at a scientific researcher, planetary researcher, sending spacecraft off to gather data to learn more. It's sort of an extension of the explorer and creative nature of humans. One religious perspective is we're made in the image of God, right? So we have a creative nature. In that sense, reaching out to the cosmos or to the other bodies is sort of our creative nature of going out and discovering and creating things that other people can use. So I would think of that as I shared with them how even the simple thing of your pencil sharpener has some history to it being used today. The planetary research and the scientific research is part of the, you know, if you feel that calling, it's part of the human experience to go and explore and create for yourself, but for sharing with humanity too. So in that sense, that's a little bit of philosophical side, but the technical side, that I really enjoyed and the students and even the teachers, who don't have necessarily a lot of exposure to direct discussion with people about it. You know, really just showing them a map of what a projection means by showing them a globe and a flat map and how you would project that onto... or showing them, taking these models here of the different bodies of the different planets at different scales, and shining a literal flashlight on them. And rotating it to where they understand sunset and sunrise, or the phase of a moon, just in a simple presentation. Really, I would present that as sort of sparking their interest and how that might be important and how that might apply to advancing our knowledge of the solar system or of the human person... I really enjoy presenting that to the students. So in some way, maybe that element might be applied of why, why should we go and do these planetary ventures and missions and explore? 

Hargitai:

I would like to ask you about some pictures, if you can identify them, but first let me have a comment on what you said last..... because that’s -- it seems to me that what you said suggests that planetary science is not at all special because creativity, discovery is a overall human characteristic so it’s just like any other creative and exploratory activity which make it even more human in many ways and I never though of it from this perspective.

Isbell:

That’s a nice way to put it, thank you.

Figure 5. Patty Thomas. Credit: USGS Collection

Isbell:

Patty Thomas. By the way, some little bit of...a little personal story, Patty was a neighbor and she knew my family. So I knew her as a kid and I had her as a middle school English teacher, and then when I went through high school and I started working here, a couple years later, she started working here. So in a way, I kind of trained her in the photo mosaic process. She was my English teacher first, though.

[End]