Lab 9a

I. Read Bolstad Chapter 9 and answer the following questions based on reading and lecture.

1. What is spatial scope and what are the three types?

Spatial scope is the extent or area of the input data that are used in determining the values at output locations. There are three different spatial operations that act upon the input of the geographic or attribute data: local, neighborhood, and global operations. Local operations only use data at one input location to determine the value of the corresponding output location. Neighborhood operations use data from both an input location and the adjacent locations to determine the output value. Global operations use data values from the entire input layer to determine each output value.

2. What are the two types of Algebra used in queries? Give an example of each.

Set algebra and boolean algebra are the two types of algebra used in queries. Set algebra uses operations that include less than (<), greater than (>), equal (=), and not equal (<>). Some examples include State = California. Boolean algebra uses the conditions AND, OR, and NOT. Some examples include State = California AND City Population > 1,000,000. This will give you all the cities in California that have a population greater than 1,000,000.

3. What are the different types of spatial selection operations?

There are two types of spatial selection: adjacency and containment. Adjacency is used to identify features that "touch" other features. They can "touch" in raster when one cell is next to another one, and in vector they "touch" when two polygons share a line or a node. Containment is used to identify features that contain or surround other features. An example of this is when all the states are selected that contain a portion of the Mississippi River.

II. AFTER completing Ormsby Chapters 10 & 11, complete the following exercise.

4. Is there a feature dataset in the geodatabase?

Yes, LosAngeles is a feature dataset.

5. What features classes are present?

PtDumeQuad, Vegetation, Wetlands, and Wetland_Project are all feature classes.

III. Exercise 1: Prepare (simplify) a vegetation layer for the Los Angeles region for further spatial analysis.

6. How many features (records) exist in the Vegetation feature class in the Lab9aData.mdb geodatabase?

There are 10,896 features in the Vegetation feature class.

7. How many features (records) exist in the new VegCov feature class after running the dissolve operation?

Now there are only 9 features in the feature class.

8. How many features (records) exist in the new “VegCov_Clip” feature class?

Now there are only 8 features in the feature class.

IV. Exercise 2: Generate a layer of Riverine wetlands that fall in the Point Dume quad. 

9. How many wetland features (records) were selected?

There are 404 wetland features selected.

10. How many features (records) were selected?

There are 123 features selected.

§ Capture a screenshot (Alt PrtScr) of your final Riverine layer and paste it into this document.