QUIZ #1
NAME: Katie Riley
1. What is a layer?
GIS maps are made up of layers (also called collections of geographic objects that are
alike). Layers may contain features or surfaces on a GIS map. They can be rivers, lakes,
cities, etc.
2. What is a feature? What kinds of features are there?
Each geographic object in a layer can be considered a feature (i.e. each river, city, lake).
They have sizes and can come in a continual amount of shapes which luckily can be
shown as three geometric forms (a polygon, a line, or a point).
3. What is a surface? Specifically, what is a raster?
It is a layer that is not a collection of geographic objects like other layers. It is a single,
continuous expanse which changes from one location to another according to a particular
factor. An example would be an ocean layer which changes in relation to water depth. A
raster is the most common kind of surface and is a matrix of identically sized square cells.
Individual squares represent a unit of surface area and contains the measured or estimated
value for that particular location.