downloaded from the Census Bureau, or anywhere else, may need to be modified to suit your purposes. A great example is when you downloaded the county file. You had no option to download a county file only for your state. The only file given was at the national level, containing all counties for the entire US.
For the following exercises, it would be better to have a shapefile of counties only in your state (like the place shapefile). How do you do that? The Census Bureau does not provide the shapefiles that way. However, it is easy to carve up shapefiles. In the next few steps, you’ll isolate your state’s counties and create a new shapefile that contains just those counties.
1 1.In the table of contents, right-click the place (Cities) shapefile, and then click Open Attribute Table.
2 2.Find the column titled StateFP (the third column from the left), and make a note of your state’s two-digit FIPS code. For Alabama, this code is 01. Close the attribute table.
1 3.In the table of contents, right-click the county file, and then click Open Attribute Table.
2 4.Right-click the StateFP column heading, and then click Sort Ascending to organize the table by state. Scroll down and find the first record in the StateFP column that corresponds to your state’s FIPS code. Finding the code for Alabama is easy. The code for the state is 01, so the counties in this state are at the top of the attribute table.
1 5.Once you find the first record for your state, click the first gray cell at the beginning of the row that contains the first record for your state. Clicking the cell creates a bright-blue highlighted record on that line item. Continue to highlight the remaining records for your state by dragging the mouse down the records (you must be on the beginning gray cells to drag highlighting). Highlight all records in your state.
2 6.It is important to close the attribute table now. Notice that counties in your state are highlighted on the map. The attribute table and map are linked. You may need to zoom in to see your state more closely.
Now you’re going to create a new shapefile for just those counties in your state.
1 7.Right-click the Counties layer name in the table of contents. Click Data, and then click Export Data. Leave all default options, except click the Browse button and navigate to your save folder (under Folder Connections).
1 8.Name the file your state’s name plus Counties—for example, “AlabamaCounties.” From the “Save as type” list, select Shapefile. Click Save, and then click OK. When prompted with the box that says, “Do you want to add the exported data to the map as a layer?” click Yes. Notice that a new layer appears in the table of contents.
Now you can organize things a bit. The US county layer is no longer needed. So you can remove it.
1 9.In the table of contents, right-click the US county layer name (this file is your original county file), and then click Remove. Drag the place file into first position in the table of contents. Notice all the cities in your state, as well as all the counties.
TIP Never include spaces in file names.
Save the project
1 1.On the File menu, click Save As.
2 2.Navigate to your save folder.
3 3.Type a name for this project. Call it mystate.mxd.
4 4.Click Save. Notice in the upper-left corner, your workspace has been given this new name.
5 5.Click the x in the upper-right corner to close ArcMap.
SAVING A PROJECT
Saving, although technically easy, is more complicated than it appears. When you “save” a project, ArcMap saves the project as an .mxd file or ArcMap document. The .mxd file functions as a pointer file to all the files that make up the project. If you sent the .mxd file to someone, they would not be able to open it without all the files that make up the project.
| CHAPTER 2 | KEY CONCEPTSworking with multiple layerschanging map colorscreating labelscreating layoutscreating legendscreating titlesusing scale barsusing north arrows |
Creating basic maps and layouts
Reference maps are basic, traditional maps like those you see in atlases. Their purpose is to illustrate geographic boundaries of a given area, such as cities or counties. These types of maps are the cornerstone of cartography. Layouts contain titles, legends, north arrows, scale bars, and many other graphic features. It is important that you learn to create layouts that help your reader quickly understand your map.
In this exercise, you will make your first map.
[ You will need to download all chapter data files from esri.com/GIS20-3.
Creating a reference map
A key point of this exercise is to teach you to effectively color-shade and label multiple layers in a map. In this example, counties and cities are used.
Open the project
1 1.Open ArcMap. (If you don’t know how to do that, see chapter 1, “Open ArcMap.”) Unlike adding a shapefile to ArcMap, here you must open your saved project. To do that, click File (upper left), then click Open, and then navigate to your save folder. Select mystate.mxd. (If you are unable to find this file, you can access a similar one in the data files at esri.com/GIS20-3, in the chapter 2 folder.)
Change layer colors
Change the layers’ colors (color, fill, outline), which is called “changing the symbology” in ArcMap, so you can easily see each layer in the map.
For the county layer, follow these steps:
1 1.In the table of contents, right-click the county file layer name, and then click Properties. By the way, “right-click > properties” is the answer to nearly every question going forward.
2 2.Click the Symbology tab. Click
