Lab goals: The purpose of this lab is to: 1) teach you how to navigate in and complete some simple tasks with ArcGIS 9 software, and 2) learn about the structural geology of Toadstool Geologic Park in northwest Nebraska. This and other localities in the central Great Plains offer us the opportunity to investigate episodes of intraplate strain. Joints, veins, arrays of small faults, and subtle flexures combine with intraplate earthquakes to indicate that while the interior of plates are relatively 'rigid' they do deform a bit. This subtle deformation can be quite important for fluid migration, erosional patterns, and erosion/deposition dynamics. Later on in the semester you will build your own small GIS database for some locality of Great Plains strain.

What you should turn in: Having navigated and manipulated the database information in ArcGIS 9 a little I would like you to explore what might be learned from this type of data in a GIS environment. Come up with three simple statements that describe some aspect of the pattern of faulting, and then print of an image to support each statement. The image should have a scale. Come up with two statements that summarize something about vein attributes. Again you should support your statements with exemplary images. Choose the wording of your statement carefully. So your final hardcopy product will be 5 one-sentence statements, connected to 5 map images.

Navigating in the ArcGIS environment: The below is intended to be step-by-step instructions to help you complete this lab. You might check them off as you complete them.

• Copy the folders Toadstool and Harlan on the CD to the C drive. ArcGIS assembles files and part of the master (.mxd) file are the addresses of the other files. If those addresses are wrong, ArcMap can't find the files. For the .mxd file you will work with, the Toadstool folder needs to be on the C drive. You can reconstruct pathways to the original files, but we can save that for another lab and another day.
• If you can save changes you make while working in the program, right click on the folder icon, and deselect the read-only option. This way you can save changes to your C-drive version.
• Navigate into the ToadstoolGIS folder and into gisfiles folder within and double click on toadtotal.mxd. The mxd suffix tells you that this is a ArcMap master file, that opens up an already constructed GIS database. Two windows should pop up. To the right is a map and to the left is a list of layers.
• At the top choose the View tab, and the select the Data View option. This program was saved so that the Layout View comes up. The Layout View is where you put the finishing touches on a map, and consider its graphical presentation. The Data View is where you add, delete, analyze and manipulate the various layers of information. When you want to produce a finished product you can change back to Layout View.
• Note the Tools bar with the small magnifying glass icons at top, one with a plus sign to zoom in and the other with a minus sign to zoom out. Note also the scroll bars on the bottom and right of the map window. Select the zoom in or zoom out tools, and use these to scan through the map area and become familiar with the landscape and plotted geology.
• Note the small boxes in the Layers window just to the left of listed layer names. Some of these are checked and some are not. Experiment to see what happens when you check of uncheck them.
• Right click on the faults layer and select the Open Attribute Table option. Scroll through the table that opens up. Here is the data behind the map view. Note that not all the data is being used or displayed in the map window. You will learn one way to explore the other columns of data in the table in a map view. In this lab, if you want you can simply move the table over to the other screen for later reference. Otherwise you will want to close this window.
• Right click on the fault layer and a box will open up and check the Label Features option. What happens on your map view? Right clicking often is a way to look for possibilities when you want to do or change something. What type of information are the faults being labeled with (you might check the Attribute Table)? Things can get pretty cluttered, so you might want to turn the Label Features option off.
• We are now going to create a new layer and classify information in it. Specifically, we are going to see what the spatial variation in average vein thickness is.
  • Navigate and zoom in on one of the vein fields.
  • Right click on the veins layer and choose the Copy option.
  • Go up to the very top of the Layers window and right click on Layers, and choose the Paste Layer(s) option. The new layer should now be listed in the layers window.
  • You should be able to type in a new name for this copied layer. Vein thickness might be a good descriptive name. You can change the name of any layer by double left clicking on the name itself, and then typing in the new name.
  • Now right click on this new layer and choose the Properties option at the bottom of the list. A fairly complex window full of options should pop up. This is a very important place in this software. Here you can change what information is displayed, and how it is displayed. It is also where you can classify your data, a first step to analyzing spatial patterns.
  • If not already selected, choose the Symbology tab at the top of your Properties window.
  • In the subwindow to the left choose the Quantities option. Highlight the Graduate symbols option. This allows you to classify a column of data and plot a symbol at the specified location whose size or color is a function of the data value. Here we can plot the average vein thickness measured at each location.
  • We still have to tell the program what column of data in the Attribute Table to classify and plot. In the larger internal box in the window find the Fields Values scroll box and choose AVERAG_TH choice. A suite of graduated symbols should appear in the Symbology window. There are all sorts of options you can explore here, but to start out with it may be best to use the default symbols.
  • Select OK and see what is now plotted on your map.
• One way to get output is to export the map window as an image. Under File choose the Export Map function and follow the instructions to save the image as one of several formats. An important part is to choose the right format with the Save as type scroll box below. Jpeg is the easiest to work with. This can be pasted into a Word file.
• If you want you can also open the localities.mxd file and explore it.
• More description of how bring your lab data into the ArcGIS environment and on the Toadstool project exists here. This would be good preparation material for our field trip. Cheers!

Copyright Harmon D. Maher Jr., This may be used for non-profit educational purposes as long as proper attribution is given. Otherwise, please contact me. Thank you.