Exercise for Week 6: Drafting maps on the computer and photo interpretation.

This week will be dedicated to learning how to produce maps on a computer platform. Again it is basically a week long introduction to a much larger topic - actually two of them - photo interpretation and map making using a computer. We have an entire course devoted to computer cartography in the department. You can still learn a lot in a week's time through this exercise. Map making has an important aesthetic component to it. A goal is to have an informative map that is both truthful, as easy to understand as possible, and pleasing to the audience's eye.

Your effort this week is going to be dedicated to producing a map of geologic and/or geomorphic features in some area of interest. The purpose of the map is then to display the variety, patterns and geologic relationships of the geomorphic features. I can suggest choosing images I have made available of volcanic features in the Capulin area or the Carrizozo area of New Mexico, but there are lots of other good possibilities. Some parts of the Sand Hills can make a good choice. For this initial foray into photointerpretation and computer mapping you want to find an area with several striking and simple features that you can identify.

First you need to get the information and imagery you need to draw the map. For the Capulin and Carrizozo areas the images are available on a CD - just ask. Otherwise, downloadable USGS air photo imagery can be found at the Microsoft Research Maps site as described below, or you can also capture an image using Google Earth. The terraserver site has evolved a fair bit through the years, and will likely continue to do so, and so you may not find it exactly as described below.

Obtaining your base map imagery from terraserver that you are going to photointerpret:

Look at your image carefully and decide what you are going to map and how different features will be displayed on your map. this is crucial. You must understand what you are mapping before you can create maps.

This will involve identifying what are the geomorphic features to be mapped. You should spend some time with this. If need be, refer to your physical geology or physical geography or other text books to refresh your memory as to what type of geomorphic features might be present in a given type of terrane. Ask your classmates what they can see in the image. Get feedback from me. Take the time to understand what you are seeing. You should make a list of geomorphic features are information you want to include in your map. You don't have to describe everything that is there - pick 3-5 features of interest. This list will be the start of your map legend.

For the Capulin area I would suggest mapping the following features:

For the area W of Carrizozo I would suggest mapping the following features:

For each feature think of how it might be best represented on the map. Should it be represented by a line or a polygon (see lecture notes)? What should be the character of the fill if it is a polygon? As you do so think about how easy it will be to distinguish one feature's representation from another when they are adjacent. Very similar shades of grey might be difficult to distinguish if you are printing out in black and white.

Drawing your map in Inkscape:

The final product should be a jpg file of the map you have constructed (you can export from Inkscape to create a jpeg file), along with a map explanation and a less that 250 word text description of the map stressing what information it conveys. The description should be as specific as example, and include timing relationships, and inferred geologic history. The image should not be included as part of your map, just your interpretation. You should also include a copy of the photo if it is not from Capulin or Carrizozo. Remember that the lab printer only does black and white. Do not email your exercise to me.

Don't hesitate to come to me with questions or feedback.

Copyright by Harmon D. Maher Jr.. This material may be used for non-profit educational purposes if proper attribution is given. Otherwise please contact Harmon D. Maher Jr.