GEO 481 Lab Geographical Information Systems Spring 2019 Tutorial: Editing the Symbology

Display the Data in ArcMap Open ArcMap -> select a new empty map Add Erie.shp to ArcMap. (The Erie shapefile contains census tracts.) 2

View the Attribute table. Right click this shapefile in the table of contents.  Click "Open attribute table" to view the attribute table. 3

We will map the population distribution in Erie County, NY. Variables We will map the population distribution in Erie County, NY. Variables Meaning Persons Tract Populations Households Number of Households in a Tract P_C_Income Per Capita Income Hhld_Units Total Housing Units Md_Y_Built Median Year Houses Built Md_G_Rent Median Gross Rent Md_Rent Median Rent Value 4

Right click the Erie layer –> select Properties –> select Symbology Save changes and leave the dialog open Save changes and close the dialog box

Types of Symbology in ArcMap There are five display options: Features, Categories, Quantities, Charts, and Multiple Attributes In this lab, we will focus on Quantities. 6

Select “Quantities” -> Select “Graduated colors” If necessary, the data can be normalized by “Area” or another field. Normalization is often important for representing counts. E.g., population density is generally preferable to count of population. “Value” “Normalization” What’s mapped = 7

Change the number of classes, classification method, Or manually move the break values Tips: avoid these: 7+ classes in shades of one color Red + green in one map

Right click in this area to make changes to the labels

Rename the variable: Click the variable name to select wait and click again to activate Enter the meaningful name (include unit if applicable) Tips: Layer name can be changed the same way.

Save the map document Click File -> Save to save the map document to your own folder. By saving the ‘.mxd’ file, you will be able to use the same settings to create similar maps in the future. Make sure you save it multiple times in the process of making the map.

Right Click  Properties  Symbology Summary and Tips Right Click  Properties  Symbology Symbology types (graduated colors) Color ramp; level of colors Classification Variable name and label Save the .mxd file frequently!

Practice Questions Try: visualize a different variable. Question: Do you see any patterns (e.g. spatial variation)? What are the similarities or differences between this variables and population density? 13