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2. Symbology: Change how the map looks

We will change the visual of the USA_48 layers using Symbology. You might notice an arbitrary, peculiar-looking polygon in the middle of the USA_48. It helps to compare how map projects present the conterminous US differently when we change the layer’s spatial reference.

1. Right-click the USA_48 layer, choose Symbology

2. In Primary symbology, choose Unique Values

3. In Field 1, choose STATE_ABBR

Now, we will differentiate the “peculiar-looking” polygon in the state layer from the rest of the state boundaries (heads-up, again: this polygon acts like a “shape-shifter” when we change map projections!). Click “More” in the Classes tab and choose “Remove all”:

Screenshot of the 'Symbology' pane in GIS software for the 'USA_48' layer. The primary symbology is set to 'Unique Values' using the 'STATE_ABBR' field. A pastel color scheme is applied to represent different state abbreviations. A table below lists symbols, values, and labels for states like AL and AR. An open dropdown menu labeled 'More' shows options including 'Include all other values' and 'Show count'.
Symbology settings in a GIS application for the ‘USA_48’ layer, showing unique value classifications by state abbreviation with customizable color schemes and symbol options.

All state polygons disappeared. We will make it revisible with mono-color.

4. Click the More button again, then click “Include all other values.“:

Screenshot of the Symbology pane in ArcGIS Pro for the 'USA_48' layer. The primary symbology is set to 'Unique Values' using the 'STATE_ABBR' field. A pastel color scheme is applied. The Classes tab shows one entry labeled '' with a gray square symbol. An open 'More' dropdown menu lists options such as 'Include all other values,' 'Show count,' 'Refresh count,' and others, with some options grayed out.
Symbology configuration for the ‘USA_48’ map layer in GIS software, using unique values based on state abbreviations with customizable color schemes and symbol options.

4. We will differentiate the “peculiar-looking” polygon using a contrasting color.  Click the green-colored “+” icon, highlight ZZ at the bottom of the table, and click OK:

Screenshot of the 'Select values to add' window in the Symbology settings for the 'USA_48' layer in GIS software. A table displays U.S. state abbreviations with corresponding colored square symbols under columns labeled Symbol, Value, and Label. States include NC, ND, NE, NH, NJ, NM, NV, NY, OH, OK, OR, PA, RI, SC, SD, TN, TX, UT, VA, VT, WA, WV, WI, WY, and ZZ. 'OK' and 'Cancel' buttons are located at the bottom right.
Symbology configuration dialog in mapping software for the ‘USA_48’ layer, showing a table of U.S. state abbreviations with corresponding color-coded symbols and labels.

5. Your current map looks like the figure below:

Map of the United States with a gray overlay and a blue circular highlight centered over Kansas, Oklahoma, and Texas. The left panel displays the 'Contents' pane with layers 'USA_48' and 'World Topographic Map' under 'Drawing Order.' The right panel shows the 'Symbology - USA_48' settings, including options for primary symbology, color scheme, and layer configuration.
GIS map of the United States with a light blue highlight over the central region, displayed alongside contents and symbology panels.

Stop and clarify: Is it a GIS issue or a software issue?

Throughout the lab activities, you may wonder WHY we should follow the step-by-step instructions for WHAT. For example, you might want to ask what the goal of steps 1-5 so far is. I would answer that we are learning about how to use the ArcGIS Pro “software” to change the colors to make the layer more visually convincing.

 

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Intro GIS Labs Copyright © by yurikim. All Rights Reserved.

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