GIS Terms and Definitions

ArcObjects

ArcObjects is the framework upon which ArcGIS has been built. It is a collection of software components based on the COM protocol, which allows for the customization and extension of the core software functionality. Coverage A collection of data that has a common theme, and is considered a single unit.

Feature Class1. A classification describing the format of geographic features and supporting data in a coverage. Coverage feature classes for representing geographic features include point, arc, node, route-system, route, section, polygon and region. One or more coverage features are used to model geographic features; for example, arcs and nodes can be used to model linear features such as street centerlines. The tic, annotation, link, and boundary feature classes provide supporting data for coverage data management and viewing.

2. The conceptual representation of a geographic feature. When referring to geographic features, feature classes include point, line, area, and surface. Feature Dataset:A feature dataset is a collection of feature classes that share the same spatial reference. GEMS Datastore: The relational database that Bentley SewerGEMS uses to store model data. Each Bentley SewerGEMS model uses two main files for data storage, the datastore (.MDB) and the Bentley SewerGEMS Modeler-specific data (.stsw). Although the Bentley SewerGEMS datastore is an .mdb file, cannot be a geodatabase.

Geocode - The process of identifying the coordinates of a location given its address. For example, an address can be matched against a TIGER street network to determine the location of a home. Also referred to as address geocoding.
Geodatabase - Short for geographic database, a geodatabase stores spatial and descriptive data in an efficient manner. Geodatabases are the standard file format for ArcGIS v8 and later. Layer: Layers contain spatial data according to similar subject matter. Conceptually, layers in a database or map library environment are exactly like coverages. Layers are the standard GIS data format for ArcView 3.x and earlier.
Metadata - Additional information (aside from tabular and spatial data) that makes the data useful. Includes characteristics and information that are required to use the data but are not contained within the data itself. Relate A temporary connection between table records using a common item shared by both tables. Each record in one table is connected to those records in the other table that share the same value for the common item.
Relational Database - A database in which the data is structured in such a way as to associate tables according to attributes that are shared by the tables. Relational Join: The process of merging two attribute tables using a common item.
Shapefile - A file format that stores spatial and attribute data for the spatial features within the dataset. A shapefile consists of a main file, an index file, and a dBASE table. Shapefiles were the standard file storage format for ArcView 3.x and earlier.
Spatial Reference - The spatial reference for a feature class describes its coordinate system (for example, geographic, UTM, and State Plane), its spatial domain, and its precision. The spatial domain is best described as the allowable coordinate range for X and Y coordinates, m- (measure) values, and z-values. The precision describes the number of system units per one unit of measure. A spatial reference with a precision of 1 will store integer values, while a precision of 1000 will store three decimal places.