Lab #6 Symbolization and Classification

Stefanie Wieschalla

Geog 206

Part 1:

1. Symbology can be influenced by scale given that in some maps, cities can be indicated by circles or as polygons and hence the more detail the scale provides, the bigger will those symbols appear. For example cities in a scale of 1:200,000 represented as a polygon will appear differently and larger than cities in a scale of 1:13,000,000 represented as a circle.  

2. One way to access a layers symbol colors so that they can be changed is by clicking the symbol for a particular layer in the table of contents. The Symbol Selector dialog box opens. The options frame on the right allows you now to pick colors. Another way to access a layers symbol colors is by simply right clicking on the layer, choosing the layers properties option and then, when the properties dialog box opens, you need to click on the symbology tab. Now you can change color.

3. One would access the graduated symbols classification option by double clicking the layer name of one’s choice to open the layer properties dialog box. Then one needs to click on the symbology tab. In the show box, click Quantities. In the Quantities column one can find the option “graduated symbols”.

4. Five other symbology styles (in addition to ‘Conservation’) that are available to customize your features are for example: Crime Analysis, Caves, Survey, Weather and Forestry.

5. One could permanently save layer symbology for a later use by right clicking the layer of one’s choice in the table of contents and then click save as layer file. In the save layer dialog box, navigate to the folder you were working with, accept the default name and then click save.

6. Pyramids can help raster data display faster by retrieving only the data at a specified resolution that is required for the display. With pyramids, a lower-resolution copy of the data displays quickly when drawing the entire dataset. As you zoom in, levels with finer resolutions are drawn; performance is maintained because you're drawing successively smaller areas. The database server chooses the most appropriate pyramid level automatically based on the user's display scale.

7. One would quickly and temporarily change a layer name to aid display in the Table of Contents by clicking once the layer you want to rename, wait a moment and then click again. Now the name is highlighted and the layer is ready to be renamed.

8. Dividing one attribute by another to find the ration between them is referred to as normalization. It is mostly used to calculate density.

9. Dot density maps could be misleading because the dot placement is random within each country and hence the arrangement of dots on a map will not match the graphic exactly. This is especially confusing when focusing on small areas.  

Part2: