Eyes in the Sky II > GIT Web Course > Module 2 > Week 6 > Intro to Symbolization > Introduction to Symbolization in My World

Week 6: Following Rivers Through Time

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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.

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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

My World Icon
  • 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.
    5 LA Rivers project 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 add 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.
  • The cities layer has been added to the map. Don't worry if the color of the dots is different.
    6 cities has been added to map
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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.
    • 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.
      7 show table of active layer
    • 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).
      8 table is open
    • Scroll across the Table of Layer. 9 use scroll bars to move

  • What type of data is given about cities?
  • 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?
  • 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.
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Adjust the Color, Size, and Type of Symbol Used to Represent Features on the Map

10 edit appearance 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.

    • 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.
      11 edit appearance on map

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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
  1. Double- click on the Louisiana cities layer name in the Layer List.
  2. The Edit Appearance window will open.
    11 edit appearance on map
    • Choose Shape by: Uniform
    • Shape Circle

    • Size 20%
    • Color Brown
    • Click OK and click Apply
  3. In this map, Louisiana cities are now represented by Brown dots.
    14 brown cirlces for cities

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.

After double clicking on the preset color choice these color Swatches are displayed in the Edit Color window.
15 swatches edit color
You can also select the HSB custom color option to adjust Hue, Saturation, and Brightness.
16 hsb
In addition, you may want to select the RGB custom color option to adjust Red, Green, and Blue color options.
17 rgb

In this map, Louisiana cities are represented by bright green custom colored dots.
18 bright green 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
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.
19 change shape to triangle

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.

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

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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
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%.
21 size edited

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.

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

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Click on the movie to start playing.

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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
    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.
      23 area name random
    2. This polka dot map of cities in Louisiana is the result.
      24 area name random on map

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.


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Click on the movie to start playing.

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Create a New Annotations Layer to Label Features of a Layer

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.) To make a labels layer in My World, change to Edit mode and create a new annotations layer.
  • Click the Edit tab to change to Edit mode. A new window will open.
    25 in edit mode
  • Click the Create a New empty Layer Button in the upper left-hand corner of the window. It looks like a sheet of paper.
    27 create a new empty layer
  • Choose the New Layer Type "Annotation".
  • Select the following options for your new layer:
    • Name: Parishes labels
    • Create Annotations for an Existing Layer or Selection
    • Annotation Source: Parishes; Source Field: NAME
    • Annotation Appearance: Font: LucidaSans: Size 9.0;
      • Style Plain; Alignment: Left
      • Color Black and Background Color: White - 0% Transparent. Click Apply.

    • 28 create new empty layer boxes filed in
    • Click Create Layer.
  • Return to Visualize mode, to check your new layer's appearance. If needed, you can do further editing of the layer's appearance in this mode.

Quit My World and do not save the project.

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Click on the movie to start playing.

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Explore More If You Have Time


  • Explore symbolizing the EPA Ecoregions 2004 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 U.S. States layer.
  • Experiment with the online color adviser for maps ColorBrewer by the author of Designing better Maps, Cynthia Brewer.

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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.
  • Look below the movie window for the file download link.

    Save Movie from CMS listing

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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.

Movie Icon Changing Symbols My World

Movie Icon Unique Symbols My World

Movie Icon Labeling Features My World

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iPod Versions

Download these version to play on your iPod or iPhone.

Movie Icon Changing Symbols My World

Movie Icon Unique Symbols My World

Movie Icon Labeling Features My World