Exercise: Thematic Mapping—Qualitative Mapping using nominally scaled data

Geography 256/556

Instructions and answer sheet (Graded, 10 points)

Exercise: Thematic Mapping—Qualitative Mapping using nominally scaled data

Purpose: to introduce thematic mapping in a GIS environment, to combine graphical elements and feature types to create visual variable used in symbolizing qualitative thematic maps.

Problem: Map design for qualitative or nominally scaled data involves the appropriate selection of symbology in order to make interpretation on the part of the map audience as error free as possible. The number of themes (attributes) should be limited to aid the map reader. In this lab exercise you will experiment with symbology for several features in DeKalb County, Illinois. Remember, visual variables (symbols) are created by manipulating the geometric objects representing feature types using the graphical elements as discussed in lecture. You will be mapping toxic release sites in relation to land uses, urban areas, and streams.

Note: Be sure to copy the contents in the folder from Blackboard to your class Lab 9 folder (to your z-drive folder).

Open Exer9.mxd and navigate to your lab 9 folder and connect to in the ArcCatalog. (First, make sure the data frame window’s coordinate system is set to Geographic Coordinate Systems | North America | NAD 1983.) Open the personal database DeKalbCountyLU.mdb (see Materials and Methods below).

Materials and Methods: The feature layers found in DeKalbCountyLU.mdb are as follows (with data source)—note the icons to the left of the layer names. These icons indicate the geometric object used to represent each feature.:

DeK_border (USDA)

DeKcounty_landuse (USGS)

Kishwaukee_1 (USGS)

Kishwaukee_2 (USGS)

LowerFox_1 (USGS)

LowerFox_LittleRock_2 (USGS)

DeK_TRI_sites (US EPA)

DeK_urban (US Census)

See your lecture slides for the visual variables table.

Part I. Adding Layers and Answering Questions about the Symbology/Graphical Elements

Used (Steps 1 through 5, 7 points)

Step 1. Add the county border layer: DeK_border

In the Symbol Selector (click on color patch under the Layers group in the TOC) and select “Hollow”. Next, select “edit symbol” button and the select the “Outline” button. Choose the appropriate boundary symbolization.

1a. (½ point) What is the feature type/geometric object and graphical element used to create this visual variable or symbol?

Step 2. Add the land use layer: DeKcounty_landuse

Double-click on the layer name to open Layer Properties > Symbology > Categories. In the Value Field pull-down menu select the field “LANDUSE” and then select the button below labeled “Add All Values”. Using the up-down arrows group each land use type by similarity. For example group agricultural uses together and group built land uses together. Double click on each land use type and pick a logical symbol to represent it. Symbols can be found in the Symbol Selector window—if you don’t see one you like, try typing in a keyword like commercial or orchard in the pull down menu. Remember you can also edit your symbols. Do this for each of the 15 land use types and remember to group them in a logical order.

2a. (1 point) What are the feature type/geometric objects and graphical elements used to create this set of visual variables or symbols? Provide two examples that use different visual variables.

2b. (½ point) What is the dominant land use type in DeKalb County?

2c. (½ point) Are the symbols that you used geometric/abstract, mimetic, or pictographic?

Step 3. Add the following four stream layers:

Kishwaukee_1

Kishwaukee_2

LowerFox_1

LowerFox_LittleRock_2

Use the appropriate graphical elements for these feature types (click on feature in the TOC). Be sure to distinguish between the two sizes of streams. Label the larger streams in italics (this should show up in the final map).

3a. (½ point) What are the feature type/geometric objects and graphical elements used to create this set of visual variables or symbols?

3b. (1 point) How many rivers are there in DeKalb County? What are the general directions of flow for the largest streams? (Hint: observe the relationships of the smaller streams to the larger streams. Can you tell from the orientation of the streams; which direction the two largest streams are flowing?

Step 4. Add the Census designated urban layer to the map: DeK_urban

Click on the color patch and then in Symbol Selector find the appropriate boundary symbol. Determine which towns are associated with the urban areas (you may need to go to an external source) and label the urban areas (at least four). You can, using editor, go into the attribute table and enter the correct names.

4a. (½ point) What is the feature type/geometric object and graphical elements used to create this visual variable or symbol?

4b. (1 point) Provide four land use types that can be found within any of the urban boundaries.

Step 5. Add the toxic release inventory layer: DeK_TRI_sites

For each chemical use a unique visual variable/symbol.

5a. (½ point) What are the feature type/geometric objects and graphical elements used to create this set of visual variables or symbols?

5b. (½ point) Which chemical is the most common (released or potentially released from each facility)? How many facilities, regardless of chemical, can be found in an urban area?

5c. (½ point) Are the symbols that you used geometric/abstract, mimetic, or pictographic?

Part II Compose the final map (3 points)

Step 6. Compose Final Map with Appropriate Cartographic Elements (Map, Title, Neatline, Data Sources, Legend for the layers, Name of map author, North arrow, and RF and graphical scale bars). Export the map as a JPEG.

Note: Compose your map in layout view. Your instructor and/or the TA will help you in getting the map elements into the layout view. You can move the layers above and below each other to make interpretation easier for the reader. The title should reflect what you are trying to show (what) and where (DeKalb County). Put the years 2000-2010 for “when”. Insert your JPEG map below.