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

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

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

4. 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

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

6. 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

7. 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

8. 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

9. Right click in this area to make changes to the labels

10. 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.

11. 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.

12. 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!

13. 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