GIS

Question 1

What is GIS?

Answer 1

A collection of computer hardware, software and geographic data for capturing, managing and displaying and analysing spatially referenced information

Question 2

What is vector and raster data?

Answer 2

Vector is points, line and polygons and raster is a grid cell mesh with each cell having a spatial referemce and an attribute value

Question 3

What is spatial and attribute data?

Answer 3

Spatial data is the location of a point and attribute data provides characteristic about the spatial data

Question 4

What is reclassification?

Answer 4

A techniques used to create a new categorical attribute in a data set. Each gridcell is assigned a new value. You take the original info and change the categories so the info is shown is a differnt way and only used for raster data.

Question 5

What are boolean operators?

Answer 5

Identify gridcells according to a set of criteria (OR AND NOT)

Question 6

What is a cartographic model?

Answer 6

Is a flow diagram to plan the steps and sequence of operations in a GIS analysis (final layer map is the aim)

Question 7

What is Map classification?

Answer 7

Bring together two classified variables into one so that the new final image tells us a combination of 2 classifications. More attributes means larger possibilities of combinations therefore interpretation can be more difficult. We use the raster calculator to cross tabulate 2 attributes together for a final classification map.

Question 8

What is interpolation?

Answer 8

Predicts vlaues for cells in a raster from a limited number of sample data points. It is an estimate so not accurate therefore we need to decrease this by increasing the sample size.