Unformatted text preview: . 36 Right-click the country layer in the TOC and choose Properties. In the Layer Properties dialog box, click the Symbology tab. In the Show box, click Categories, then click Unique values. Click the Value Field drop-down arrow and choose CNTRY_NAME. Click Add All Values. From the Color Scheme drop-down list, choose a color scheme that you like. Two 37 Click OK. ✦ Exploring Basic GIS Functionality GIS f or the Urban Environment EXTRA CHALLENGE
Create a proportional symbol map of city populations
This task shows how to adjust the size of the city points to match population size. EC 1 At the bottom of the TOC, click the Selection tab. Check cities and uncheck the other layers. Return to the Display tab of the TOC.
Because the cities layer contains major cities throughout the world, the class breaks will
reflect the minimum and maximum populations of all the world’s major cities, not the minimum and maximum populations for the major cities of West Africa only. To correct this, you
must select the cities of West Africa and make a separate layer from them. Then, when you
symbolize them by graduated symbol, classes based on the data range of just the West
African cities will appear in the TOC. EC 2 Using the Select Features tool, select all the cities in the West Africa countries. Once the selection is made, right-click the cities layer in the TOC, point to Selection, and click Create Layer From Selected Features.
The new layer is added to the top of the TOC. This is a temporary layer that only exists within
your current map; no new files were created on your computer. EC 3 Open the properties of the cities selection. If necessary, click the Symbology tab. In the Show box, click Quantities, then click Proportional symbols. In the Fields box, click the Value drop-down arrow and choose POPULATION. Click OK. EC 4 To make the West African cities stand out better, turn off the cities layer.
Now you should have a map showing the cities symbolized according to population—
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This note was uploaded on 03/16/2013 for the course URB 3833 taught by Professor Hachadooran during the Spring '12 term at NYU Poly.
- Spring '12