Week 6: Following Rivers Through Time

top of page

Intro to Symbolization in AEJEE

Symbolization is the process of choosing how to represent the features on a map. The symbols we choose should help describe additional information about the features on the map. Poor symbolization leads to inaccurate, misunderstood, or even deceptive information, while effective symbolization helps to communicate information quickly and clearly.

top of page

Download Geographic Data About Louisiana

• Right-click (Win) or control-click (Mac) the link below to download the zipped file to your computer.
LouisianaAE.zip (Zip Archive 25.8MB Mar16 10)
• Unzip the file. A folder called LouisanaAE will be created.
• Move the entire LouisanaAE folder into the AEJEE Data folder. (Path: ESRI/AEJEE/Data/LouisianaAE)

Launch AEJEE, Open the Louisiana Project File, and Add a New Layer

• Launch AEJEE by double-clicking its icon on your desktop or by clicking its icon in the Dock (Mac) or Launch Bar (Win).
• Choose File > Open, navigate to ESRI/AEJEE/Data/LouisanaAE, select the LA_Rivers.axl file, and click Open.
  
• A map of Louisiana is displayed when the project opens. Parishes are shown in tan and the Mississippi River is blue.
• Click the Add Data button, navigate to the LouisianaAE folder, select cities.shp, and click OK. This layer maps cities in Louisiana and should now be the top layer on your map. Note: The cites layer is automatically turned on when it is added.
Show me what this looks like
Hide
The cities layer has been added to the map.

top of page

Explore the Attribute Table of the Cities Layer

Each layer of a GIS project includes a database of information about its features. This information is presented in an Attribute Table, which is linked to the map features associated with that layer.

• Click the cities layer in the Table of Contents to make it the active layer. Right-click (Win) or control-click (Mac) the cities label in the Table of Contents and choose Attribute Table from the menu. Scroll through the fields (columns) and the data records (rows) in the Attribute Table.
Show me how to open and explore the Attribute Table
Hide
• To open the Attribute Table, right-click (Win) or control-click (Mac) the layer name in the Table of Contents and choose Attribute Table from the menu.
  
• The Attributes of cities window opens. Drag the horizontal scroll bar to examine the different fields (columns) in the Attributes of cities table and drag the vertical scroll bar to see information for the different cities (records).
  
  Scroll across the Attribute Table.
  


• What type of data is given about cities?
Show me the answer
Hide
The cities database includes the following fields.
• FID (Feature ID.)
• AREANAME (Official name of the area.)
• CLASS (The type of area: city, town, village, borough, or CDP - Census Designated Place.)
• PLACE (A numeric code for the individual places in the CLASS field.)
• FIPS (5-digit place code assigned under the Federal Information Processing Standards.)
• POP_90 (Population according to the 1990 Census.)
• POP_98 (Population estimated for 1998 by the US Census Bureau.)
• HOUSEUNITS (Number of housing units in the place in 1990.)
• AREALAND (Area of land in the place, in square miles.)
• AREAWATER (Area of water in the place, in square miles.)
• How do you find out what the field names mean?
Show me the answer
Hide
Most GIS data files that you can download come with a special file that holds the metadata. Metadata is information about the data itself and includes things like who created the data and how, such as if it was derived from other datasets. The metadata file is also the place to find field definitions that tell you what data was collected for each field.
• Close the Attributes of cities window.

top of page

Adjust the Color, Size, and Type of Symbol Used to Represent Features on the Map

When you added the cities layer, you may have noticed that it was automatically assigned a color. This initial color choice for the data is random. Compare the color of the city dots to the colors in the other layers. You may find that there is not enough contrast between colors or that the cities came in with the same color as another layer, making them difficult to see. It may be necessary to change the color of the city dots. The symbols used to represent features in a layer can be modified in that layer's Properties window.

• To open the Properties window for the cities layer, right-click (Win) or control-click (Mac) the cities label in the Table of Contents. Choose Properties from the menu. Then move the Properties window so you can see both it and the map at the same time.
  
  Show me how
  Hide
  
  

  • To open the Properties window for the cities layer, right-click (Win) or control-click (Mac) the cities label in the Table of Contents. Choose Properties from the menu.
    
  • Drag the Properties window to a location where you can see both it and the map at the same time.
    

top of page

Symbolize by Color

In the Properties window, change the color of the cities to Brown. Select the following options:

• Draw features using: One Symbol
• Style Circle
• Color Brown
• Size 6
• Click Apply and Click OK

In the Properties window, choose a color that contrasts well with the map. Explore the built in color options as well as the custom ones in the Color drop down menu.

Symbolize by Symbol Type

Instead of using dots to represent cities, you may want to choose a different type of symbol. In the Properties window, change the symbol style of the cities to Triangle. Select the following options:

• Draw features using: One Symbol
• Style Triangle
• Color Brown
• Size 6
• Click Apply and Click OK

In the Properties window, choose a symbol that you think makes sense for representing cities. Experiment with other choices in the Style drop down menu.

top of page

Symbolize by Size

If you chose triangles as your new symbol for cities, you may notice that they appear smaller than dots. In this case, you may wish to increase the size of the symbols. In the Properties window, change the size of the symbol of the cities to 10. Select the following options:

• Draw features using: One Symbol
• Style Triangle
• Color Brown
• Size 10
• Click Apply and Click OK

In the Properties window, choose a size that you think makes sense for the symbol you are using to represent cities. Experiment with other choices in the Size drop down menu.

top of page

Add Meaning to the Symbols to Differentiate Between the Features on the Map

At this point, every city in Louisiana is represented by the same symbol and with the same color. The residents of these communities will be quick to tell you that Louisiana's cities are not all the same! Using appropriate symbolization, you can communicate information about the cities beyond their locations.

In the Properties window, change the symbolization for the cities using the following options:

• Draw features using: Unique Symbols
• Field for values AREANAME
• Color Scheme Random
• Style Circle
• Size 8
• Click Apply and Click OK
Show me how
Hide
1. Right-click on the PC or control-click on the Mac the cities label in the Table of Contents. Then select Properties. Click on the Draw Features using: drop down menu and choose Unique Symbols.
   
2. Choose AREANAME for Field for values and Random for Color Scheme. The Style default is Circle and Size default is 8 points.
   
   
3. This polkadot map of cities in Louisiana is the result.
   
   

Now each city has its own color. You have taken one step towards differentiating the data in the map. However, as you can see, the map now looks like it was sprinkled with confetti. Although you have given each city a unique color, this is probably not the best way to display this information, as it is overly busy and somewhat distracting to view. In the Introduction to Classification, section you will learn a more sophisticated way to add meaning to the cities layer.

Last, use the General tab in the Properties window to name the layer in the Table of Contents something unique to this project, such as Louisiana Cities.

top of page

Label Features of Layers

Sometimes symbols are not enough information and it is preferable to actually label the map with words or numbers. In this example, we will label the Parishes by name. (A parish in Louisiana is equivalent to a county in other states.)

• Open the Properties window for the Parishes layer and label the Parishes on the map.
  
  Show me how
  Hide
  
  

  1. Right-click on the PC or control-click on the Mac the Parishes layer in the Table of Contents. Then choose Properties from the menu.
     
     
     
  2. Move the window to where you can see it and the map.
     
     
     
  3. In the Properties window, click the Labels tab. Label the features using the following options:
     
     • Label features using: NAME
     • Font Arial
     • Color Black
     • Size 10
     • Click the Effects button.
     • Click the checkbox for Background to make the background color White and click the checkbox for Use highest text quality.
     • Click OK in the Effects window.
     • Click Apply and then click OK in the labels window.
     
     
     
     

Quit AEJEE and do not save the project.

top of page

Explore More If You Have Time

• Explore symbolizing the Ecoregions layer on the map.
• Try symbolizing the Rivers layers, by size, color or style.
• Investigate adding and removing outlines on the points layers.
• Adjust the size of the borders on the Parishes layer to be larger or smaller than the US States layer.
• Experiment with the online color adviser for maps ColorBrewer by the author of Designing better Maps, Cynthia Brewer.

top of page

Movies on this Page

How to download movies

• Click the link to go to the SERC media library listing for the movie. The record will open in a new window.
• On the SERC media library page, right-click (Win) or control-click (Mac) the link (below the movie on the Flash version pages) to download the movie file to your hard drive.
Show me where to look for the download link
Hide

Look below the movie window for the file download link.

top of page

Flash Video Versions

Download these versions to play on your computer. You'll need an appropriate movie player to view the file, such as Flash Player, Real Player (Mac / Win), or Adobe Media Player.

Changing Symbols AEJEE

Unique Symbols AEJEE

Labeling Features AEJEE

top of page

iPod Versions

Download these version to play on your iPod or iPhone.

Changing Symbols AEJEE

Unique Symbols AEJEE

Labeling Features AEJEE