GIS 1 Flashcards
(47 cards)
Vector
A spacial data storage method in which features are represented by one or more pairs of x-y coordinate values forming points, lines, or polygons
Raster
A data set composed of an array of numeric values, each of which represents a condition in a square lelement of ground.
Georeferenced
A spacial data layer that is tied to a specific location on the earth’s surface for display with other data.
Feature
A spacial object composed of one or more x-y coordinate pairs and having one or more attributes in a single record of an associated table.
Point
A one dimensional feature defined by a single x-y coordinated pair.
Line
A spacial feature composed of a string of x-y coordinate vertices and used to represent linear features such as streets.
Polygon
a closed two dimensional area feature defined by three or more x-y coordinate pairs.
Node
The beginning and end point of a line feature.
Vertex vertices
A point at which the segments of a line or polygon feature change direction.
Feature class
A set of similar objects with the same attributes stored together in a spatial data file.
Attributes
Information about map features stored in columns of a table.
FID
Feature ID - a unique number assigned to every feature in a spatial data file and used for identification and tracking.
OID
Object ID - Unique number identifying a row in a table or a feature in a geodatabase feature class.
Feature Data Set
A set of feature classes in a geodatabase that share a common coordinate system and can participate in network and topology.
Thematic Mapping
Displaying the features of a spatial data layer based on values in its attribute table.
Spaghetti Model
A model that stores spatial features as a series of x-y coordinates and does not store topological relationships between features.
Topological model
A data model that stores spatial relationships between features in additional to their x-y coordinates.
Adjacency
A spatial condition that quantifies whether one feature touches another.
Connectivity
A property of linear features when they are connected to each other via junctions.
Overlap
A spatial condition that quantifies whether one feature covers all or part of another feature.
Intersection
The property of two features touching each other in whoole or in part.
Logical consistency
A measure of how well data features represent real-world features, in particular with respects to topology.
Cell Pixel
A square data element in a raster corresponding to one value representing conditions on the ground.
Discrete
Data that take on a relatively small number of distinct values.
