Week 6: Following Rivers Through Time

Intro to Symbolization in My World

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.

Download Geographic Data About Louisiana

• Right-click (Win) or control-click (Mac) the link below to download the zipped file to your computer.
LouisianaMW.zip (Zip Archive 33.6MB Jun13 10)
• Unzip the file. A folder called LouisanaMW will be created.
• Move the entire LouisanaMW folder into the My World data folder. (Path: Applications/My World /data/LouisianaMW)

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

• Launch My World by double-clicking its icon on your desktop or by clicking its icon in the Dock (Mac) or Launch Bar (Win).
• Choose File > Open Project..., navigate to Applications/My World /data/LouisanaMW, select the LA_Rivers.m3vz 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.
• In Visualize mode, select File > Import Layer from File , navigate to the LouisianaMW folder, select cities.shp, and click OK.
• My World will ask if the projection is in Latitude and Longitude, it is, so 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.
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The cities layer has been added to the map. Don't worry if the color of the dots is different.

Explore the Table of Layer of the Cities Layer

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

• Click the Louisiana Cities layer in the Layer List to make it the active layer. Then click the Show table of the Active Layer button. Scroll through the fields (columns) and the data records (rows) in the Table of Layer.
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• To open the Table of Layer "Louisiana Cities", single click the layer name in the Layer List to select the layer and click the Show table of the Active Layer button.
  
• The Table of Layer "Louisiana Cities", window opens. Drag the horizontal scroll bar to examine the different fields (columns) in the Table of Layer"Louisiana Cities" or drag the vertical scroll bar to see information for the different cities (records).
  
  
• Scroll across the Table of Layer.
  


• What type of data is given about cities?
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The cities database includes the following fields.
• 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?
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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 Table of Layer "Louisiana Cities", window.

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

The Edit Appearance window in My World .

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 Edit Appearance window.

• To open the Edit Appearance window for the Louisiana Cities layer, double-click on the Louisiana Cities label in the Layer List. The Edit Appearance window opens, move it so you can see both it and the map at the same time.
  
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• To open the Edit Appearance window for the Louisiana Cities layer, double-click on the Louisiana Cities label in the Layer List. The Edit Appearance window opens, move it so you can see both it and the map at the same time.
  
• Drag the Edit Appearance window to a location where you can see both it and the map at the same time.
  

Symbolize by Color

In the Edit Appearance window, change the Louisiana cities to Brown circles. Select the following options:

• Choose Shape by: Uniform
• Shape Circle
• Size 20%
• Color Brown
• Click OK and click Apply

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1. Double- click on the Louisiana cities layer name in the Layer List.
   
2. The Edit Appearance window will open.
   

• Choose Shape by: Uniform
• Shape Circle


• Size 20%
• Color Brown
• Click OK and click Apply

In this map, Louisiana cities are now represented by Brown dots.

In the Edit Appearance 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 chooser windows.

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After double clicking on the preset color choice these color Swatches are displayed in the Edit Color window.

You can also select the HSB custom color option to adjust Hue, Saturation, and Brightness.

In addition, you may want to select the RGB custom color option to adjust Red, Green, and Blue color options.

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In this map, Louisiana cities are represented by bright green custom colored dots.

Symbolize by Symbol Type

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

• Choose Color by: Uniform
• Shape Triangle
• Color Brown
• Size 20%
• Click Apply and Click Close

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In the Edit Appearance window, click and hold on the Shape pull down menu. Change the Shape from Circle to Triangle. In this map, Louisiana cities are represented by Brown Triangles.

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

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In this map, Louisiana cities are represented by Brown Squares.

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 Edit Appearance window, change the size of the symbol of the cities to 10. Select the following options:

• Choose Color by: Uniform
• Shape Triangle
• Color Brown
• Size 40%
• Click Apply and click Close

Show me how to change the size of the symbol of the cities

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In the Edit Appearance window, change the size by clicking and dragging the slider in the Size menu.
In this map, the size of the symbols representing cities has been changed to 41%.

In the Edit Appearance 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 Range drop down menu.

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In this map, Louisiana cities are represented by Green Squares that are 40% in size.

Show me a movie about changing the color, size, and type of symbol in My World

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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 Edit Appearance window, change the symbolization for the cities using the following options:

• Choose Color by: AREANAME
• Shape Circle
• Colorscheme Random
• Size 20%
• Click Apply and click Close
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1. Double-click on the Louisiana the cities label in the Layer List. Then select Edit Appearance. Click the Color tab, then click the Choose Color by: AREANAME. In the Colorscheme drop down menu, choose Random.
   
2. This polka dot map of cities in Louisiana is the result.