Lab 10

I. Read Bolstad Chapter 4 and answer the following questions based on the reading and lecture.

1. Would you have more problems with feature generalization and omission in large or small scale maps? Why?

You would have more problems with feature generalization and omission on a small scale map. This is because there are fewer details on a small scale map (it is zoomed out more). A large scale map, on the other hand, is zoomed in more and due to this there are more details. In addition, on large scale maps less generalization is needed.

2. What is snapping in the context of digitizing? Why is snapping important (i.e. what does it help avoid)?

Snapping is a process of automatically setting nearby points to have the same coordinates. This helps to reduce the number of undershoots and overshoots while digitizing.

3. What is COGO and how does it relate to coordinate surveying?

COGO stands for coordinate geometry, and it is spatial data that consist of a starting point with a list of directions and distances to subsequent stations.

II. AFTER completing Ormsby Chapters 14 -17, complete the following exercises.

EXERCISE A

Q: What is the feature class type (point, line or poly) for Springs?

Point

Lab 9b

1. How many counties does the State of Iowa contain? (1 pt)

 There are 99 counties in Iowa.

2. Which county in Georgia contains the largest number of people, as of the year 2001? (1 pt)

Fulton contains the largest number of people in 2001.

3. How many cities, with populations between 10,000 and 49,000, are located within the State of Washington? (1 pt)

There are 39 cities in Washington that have a population between 10,000 and 49,000.

4. How many miles long are all of the interstates in Los Angeles County? (1 pt)

The interstates in Los Angeles County are 4,105.56 miles long.

5. Simplify the UrbanBoundaries feature class so that only the urban areas of Los Angeles County are visible (Hint: you must use one of the overlay functions). Create a new feature class and save it into the LosAngeles dataset using the name LA_Urban. Include a screenshot of this new layer with your assignment. (2 pts)

6. How many acres of urban area lie within Los Angeles County, based upon your results from question #5? ( 1 pt)

There are 1,441,652.796875 acres of urban area within Los Angeles County.

7. How many zip codes have their centroid in Los Angeles County? (1 pt)

There are 522 zip codes that have their centroid in Los Angeles County.

8. Create a layer displaying the provinces of Canada using the data provided to you in the Canada feature dataset. Save this new layer under the Canada feature dataset using the name Provinces. Include a screenshot of this new layer with your assignment. (2 pts)

9. Which Native American Indian Reservations lie within 75 miles of the City of Thurso in Canada? (1 pt)

Both Kitigan Zibi Indian Reservation and Akwesasne Indian Reservation lie within 75 miles of the city Thurso.

10. Open your final and complete geodatabase in ArcCatalog. Make sure all of the feature datasets and feature classes are viewable. Capture a screenshot of the geodatabase and include this screenshot with your assignment. (1 pt)

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.