GIS FINAL Flashcards
Continuous Surface?
A surface with continuous values that can be changing
Object? Are they discrete or continuous
Items on a data model
What is Data Model?
Set of information that makes a model of the world
What are 3 types of objects?
Line, area, point
Examples of continuous surface?
Precipitation, elevation, temperature
Diff between simple & complex line?
One is straight, other has turns/changes direction
Diff between polygon & connected polygon?
One is composite, one is homogenous
What is vector data model?
Assembly of polygons, lines and points of varying shapes where each represents one or more objects
What is a raster data model?
Assembly of pixels (grid)
What are the diff types of tables?
Feature attribute table, stand alone table
What is feature attribute table?
Stores attributes of vectors and contains spatial information of the vectors
What is stand alone table?
Table w/ no spatial information and consists of any data
What are the 4 diff data types?
Integer, text, double, float
What are the hexarchies of attribute levels
Nominal, Ordinal, Interval, Ratio
Def of each attribute level?
Nominal: distinct objects
Ordinal: has hierarchy (order)
Interval (has a range-often in the decimals) but no true 0
Ratio: balanced around a true 0
What is difference between short, long, float, double?
short: 2 byte integers
long: 4 byte integers
float 4 byte integers
double: 8 byte integers
Convention for naming?
letters & numbers & underscores, no spaces
What are the names for column, row and intersection?
attribute, tuple, relation
Diff between primary and foreign key?
Primary is linked directly to a tuple, foreign links data from another table to the primary
What are the 4 relationships?
one to many
many to one
many to many
one to one
Is join temp or permanent
temp
diff between relation and join?
relation highlights/selects from both tables, join brings the two tables together
What are pros of vectors vs discrete?
Discrete info, saves storage ,topology can be applied, many attributes for one feature
Pros of raster?
Discrete & continuous info, easy overlay, easy to build from sensor information, uniform size
What are characteristics of arc?
nodes, line segments, verticies
Simple vs complex polygon?
complex has more polygons within it
What is topology?
allowing features to have spatial relationships with one another (i.e where a line is respective of another)