Introduction To GIS

Question 1

What are vectors?

Answer 1

discrete objects
point features, line features, polygon features

Question 2

What are rasters?

Answer 2

continuous data

Question 3

What type of data should be mapped with vectors?

Answer 3

objects that exist in one place and not in another
e.g. roads, states

Question 4

What type of data should be mapped with rasters?

Answer 4

a quantity that exits over the entire map area. always present; changes in value from place to place
e.g. elevation, temperature, precipitation

Question 5

Benefits of vector data

Answer 5

-can store many attributes
-precise location of features
-compact storage of information
-ideal for analysis of area, lengths, connections

Question 6

Drawbacks of vector data

Question 7

Benefits of raster data

Question 8

Drawbacks of raster data

Answer 8

-high resolution=high storage space
-storage of attributes: would need a new raster for each attribut (only numeric attributes may be stored)

Question 9

What is the difference between a large-scale map and a small-scale map?

Answer 9

Large scale= large ratio (very detailed)
1:24,000
small scale = small ratio, much bigger area
1:50,000,000

Question 10

What is the difference between the catalogue window and the table of contents? Which will make permanent changes to your files?

Answer 10

table of contents contains layers and properties. changes affect the map display only.
catalog window manages files and folders. changes are permanent

Question 11

What does it mean to “store links” to data? Why would ArcGIS use data links to make maps?

Answer 11

The map stores links to files and not the actual data. The benefits of storing links is that files can make many different types of maps, different maps don’t alter original files, and overall storage decreased dramatically.

Question 12

How could you organize your own data to prevent broken data links?

Answer 12

use organized folders and store data on the C:\ drive
develop an organizational system and use it

Question 13

How to fix a broken data link

Answer 13

In the content pane of a map, click on the exclamation point button (!) next to the layer to open the change data source dialog box.
Browse to the data source, select it, and click OK.

Question 14

What are absolute vs. Relative pathways

Answer 14

Absolute pathways always start at the top of the data tree (C:\mgisdata\usa\states.shp)
Relative paths start at the location of the map document
(…\usa\states.shp)
-use when you plan to keep data with its map documents and move them together as a set)

Question 15

interval data

Answer 15

can be negative numbers. distance between two values is meaningful, supports addition/subtraction
e.g. temperature, pH, elevation

Question 16

ratio data

Answer 16

meaningful zero point
when the value is zero, there is none of that variable
e.g. population, rainfall, median rent