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Bonus: Symbolizing Layers By Attributes
- On the ribbon, click the Insert tab.
- In the Project group, click the New Map button.
- Right-click the US_tract_1980_Harris_County feature class and select Add To Current Map.
- Above the ribbon, on the Quick Access toolbar, click the Save button.
Symbolizing Layers By Quantity
- In the Contents pane, right-click the CensusUS_tract_20101980_ByHarris_SuperNeighborhoodCounty layer name and select Symbology.
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- In the
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- Symbology pane, click the primary drop-down menu
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- and select
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- Graduated Colors.
- Use the 'Field' drop-down menu to
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- select the
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- AV0AA1980 field. NHGIS data downloads include a read-me file that defines the codes for each field (column). AV0AA1980 stores the number of
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- people within each
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- census tract.
The map view now displays a choropleth map, where the darker colors represent higher numbers of
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- people. In studying the map, it appears as if
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- there is no discernible pattern to population numbers. While this is true according to raw counts per
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- census tract, there could be differences in the
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- census tracts that are unaccounted for in this symbology. Now you will try normalizing by the area of the
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- census tracts.
- Use the 'Normalization' drop-down menu to scroll to the bottom and select the last Shape_Area field.
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Note: the projection of the census layer is GCS WGS 1984. Therefore, the layer is unprojected and the coordinates are stored in angular units of decimal degrees. Therefore, the Shape_
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- Area field is displaying square decimal degrees and the map is displaying number of
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- people per square decimal degree. This is a somewhat
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- incomprehensible unit, however, the values are still proportional to how they would be in a different unit and the relative coloring on the map remains correct.
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projecting is further covered in the Introduction to Coordinate Systems and Projections course.
- Notice that according to the density of
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- population count, the greatest amount of
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- people appear to be
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- inside
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- Use the 'Normalization' drop-down menu to select the SUM_HU100 field.
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- the major loops.
- On the lower half of the Symbology pane, click the Histogram tab.
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Discuss and test classification methods.
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- Use the 'Method" drop-down menu to select Equal Interval.
- Use the 'Method" drop-down menu to select
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Discuss and test number of classes.
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- Quantile.
- Use the 'Classes' drop-down menu to select 20.
- Use the 'Classes' drop-down menu to select 4.
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Discuss and test color schemes.
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Adding Layer Transparency
- Use the 'Color Scheme' drop-down menu to select a different color scheme of your choice.
Adding Layer Transparency
- In the Contents pane, ensure that the US_tract_1980_Harris_CountyEnsure that the Census_2010_By_SuperNeighborhood layer is selected.
- In the ribbon, click the
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- Appearance
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- tab.
- In the Effects group, slide the Layer Transparency slider or type "50" and hit Enter.
Symbolizing Layers By Category
- Use the primary 'Symbology' drop-down menu to selectUnique Values.
Use the 'Field 1' drop-down menu to selectName.
- In the Contents pane, collapse the Census_2010_By_Superneighborhood symbologyReturn the Layer Transparency slider to "0".