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FIRST GIS EXERCISE, HIST 200 – THE VERACRUZ-TO-MEXICO CITY CORRIDOR
Log into WebCT, then Hist 200 The West – Global Perspective , click on GIS data file. Inside that find the “Veracruz to Mexico City” material, click on it. A “File Download” screen comes up, asking if you want to Open or Save this material. For now, just Open (it takes about 30 seconds). Choose Extract All Files (do “nexts” and “finish.”). Find the hist200mex.mxd file (the only .mxd file, icon is a magnifying glass over a globe), double-click, it comes up like this:
The large blank space at the right is where you’ll “build” your map. The vertical list of items on the left – in what is called the legend – are the layers of information available for you to work with, sort of a table of contents for the GIS map.
On the legend, beginning with the bottommost layer (“area of interest”), click once in the empty box to the left of the words to turn this layer on. The appropriate rectangle (centered on the Veracruz-to-Mexico City corridor) should appear in the mapping area.
Notice that each layer, including this “area of interest” layer, has a little plus sign to the left of it. Click once on the plus beside “area of interest.” It should turn into minus, and expand the layer information to show you symbol type (a rectangle) and current color scheme (black).
Now go up to the next-to-bottom layer, hillshading; click the plus to expand the listing to show the black-to-white ramp for its current display, and then click inside the empty box to turn the hillshading on in the map.
It should look now look like this, as if a light-source is shining from top-left, making northwest- facing slopes lighter and southwest-facing slopes darker. Volcanoes and mountain ridges already show up pretty well, especially the nearly-conical La Malinche close to the middle of the opening screen.
Double-click on the layer title “elevations,” and in the Layer Properties box that comes up, choose the Display tab at top. Down into that box there’s a place that let’s you make the elevations color ramp any degree of transparency from 0% (which it is now) to 100% (so totally transparent it wouldn’t show up at all). Experiment with changing the transparency value, starting with maybe 10% (and then hitting OK, which tells the computer to apply it and redraw the map) and then go back and do it with higher percentages. Get it to where you think the proper amount of hillshading shows up through the elevations color ramp. Isn’t this neat? The one below, by the way, is 30% transparent.
Some improvement, but still not a good color scheme. A problem we can fix...
Double-click on the “elevations” layer title again, and when the Layer Properties box comes up, this time hit the Symbology tab at top. At the end of the yellow-to-brown color ramp bar, there is a drop-down arrow. If you click on it, you’ll get five choices, and arrows to the right of them that let you scroll up and down. Scroll down through the mono-colored ones until you hit some vivid multi-color choice. Click on it and hit OK or Apply, and it will recolor you map.
Then go back and double-click on the “elevations” layer title again, get back to Symbology, choose the color ramp drop-down arrow and scroll down and choose the color scheme on this map below:
Much more geographic looking, n’est-ce pas? But you need to have a blue ocean, so let’s color the bottom layer, “area of interest,” some nice deep blue. The way to do this is to double-click on the “area of interest” layer title, and when all the color options come up, choose the drop- down arrow by fill color, click on a nice blue, then hit OK. Map will redraw; ocean will be blue (really the whole rectangle will be blue, but since it’s the bottom layer, you only see the blue where there is no elevation data on top of it).
Now your basic map should appear something like this:
Taking shape nicely, no? Sí?
Now open large urban areas by clicking in box on legend. They show up as white, but we want them red. So double-click on the white-filled rectangle below the “large urban areas” title, hit the drop down arrow but the little fill color box at right, click on the vivid red of your choice, say OK. It will redraw.
Turn on cities (points) in legend. Symbols are too large and you want them red instead of green. So double-click on the green-filled square below “cities (points)”, then look at all the symbols available to you. Pick triangle 2, and to the right, under options, change the color to the same red you used for cities, and decrease the size of the symbol from 15 to 8. Hit OK for a redraw.
Turn on railroads in the legend. Increase size of symbol from 5 to 7. Hit OK for a redraw.
Turn on the rivers layer. Turn on the floodplains layer. On second thought, the floodplains layer makes it too messy; turn it back off.
So now you should have a pretty impressive map, something like this:
Now let’s play around with the map you’ve got, by using some more tools on the basic toolbar. Try zooming in (it’s the + magnifying glass); click on the tool to activate it, then you can either click on the map where you want to enlarge, or click and drag a rectangle you want to see closer up). Try zooming in until the elevation colors break up into their “raster” units (little squares each of a single color). Zoom out again. If at any time you want the map to the original scale, hit the “full extent” tool which looks like a miniature earth-globe. Try the “pan” tool, which looks like a hand; click on it to activate it, then put in on the map, click and drag it to slide the whole map one way or another. Use information tool to identify cities, elevations, whether RR lines are single or double-track.
One of the neatest tools is the “measure” tool, which looks like a little yardstick with arrows above it. It’s now set to measure in decimal degrees, and we want it in miles. So go to the View drop-down menu at top of page, and double-click last item, Date Frame Properties. Choose the “General” tab, and in the Display drop-down box, choose Miles. Say OK.
Now activate the Measure tool by clicking on it. Position it over Veracruz, click it and drag the line over to Mexico City, all the while watching the miles being counted off in lower left corner. This distance, as the crow flies, should be a neat multiple of 100, or very close: what is it? Then measure other distances – between volcanoes? cities? across Mexico City? Clever, no?
All this time you’ve been working in Data View, but you need to switch to Layout View to print your map. Go to the “View” item in the top toolbar, and in its drop-down menu choose Layout View. What you’ll get now is a map in a defined rectangle, inside a dotted rectangle that represents the 8.5 x 11 inch paper you’ve chosen to print on (we can’t afford for you to print really big ones so we’ve helped you “choose” this size).
File – Page and Print Setup – Landscape. Highlight frame of map, make wider and shorter. Use Insert drop-down menu to add North Arrow, Scale Bar, Title, sign it with your name(s). Ought to look something like this:
File, Export Map, rename, save as .jpg on Desktop; e-mail it to your instructor (either jsbrown @ samford.edu, or bmrobins @ samford.edu, as appropriate) as an attachment; they’ll run you off a color copy and bring it to next class. Thanks for playing.
