you need javascript for this functionality DCHC MPO - FAQs
Sorry, this page has moved!
Please click here to go to the new location.


What is a data model?

It is an abstract representation of the data used by an organization, such that a meaningful interpretation of the data may be made by the model's readers. The data model may be at a conceptual, external or internal level (as defined by ANSI).

What is a database and spatial database?

A collection of interrelated information, usually stored on some form of mass-storage system such as magnetic tape or disk. A GIS database includes data about the position and the attributes of geographical features that have been coded as points, lines, areas, pixels or grid cells.

What is a database management system (DBMS)?

A set of computer programs for organizing the information in a database. Typically, a DBMS contains routines for data input, verification, storage, retrieval, and combination.

What is a feature service?

It is the way to serve features over the Internet/Intranet and provide the symbology to use when displaying the features. Clients can execute queries to get features and perform edits that can be applied to the server.

What is a map service?

It is the way that you make maps available to the web using ArcGIS. The map is made in ArcMap, then published as service to the ArcGIS Server site. Internet or intranet users can then use the map service in web applications, ArcGIS for Desktop, ArcGIS Online, and other client applications.

What is a map template?

It is a map document (.mxd) from which new map documents can be generated. Templates may contain basemap layers or be a variety of commonly used page layouts. Map templates make it easy to reuse or standardize a layout on a series of maps.

What is a Map?

Cartography; A hand-drawn or printed document describing the spatial distribution of geographical features in terms of a recognizable and agreed symbolism. Digital; the collection of digital information about a part of the earth's surface.

What is a network?

it is a set of interconnected lines.

What is a scale?

It is the relation between the size of an object on a map and its size in the real world.

What is a spatial data standard?

It is a specification to facilitate the development, sharing, and use of geospatial data.

What is a Tile?

A part of the database in a GIS representing a discrete part of the earth's surface. By splitting a study area into tiles, considerable savings in access times and improvements in system performance can be achieved.

What is accuracy?

1)The closeness of an estimated (measured or computed) value to a standard or accepted value of a particular quantity, ie., relates to the quality of the result.

2)With regards to numbers in a mathematical table or those produced by a computer Accuracy may mean: (a) the number of significant digits in the numbers, (b) the order of magnitude of the least significant digit. ( See also Precision)

What is an attribute?

it is non-graphic information associated with a point, line, or area element in a GIS.

What is Geocoding?

The activity of defining the position of geographical objects relative to a standard reference grid.

What is Geographic Information Systems (GIS)?

A system of capturing, storing, checking, integrating, analyzing and displaying data about the earth that is spatially referenced. It is normally taken to include a spatially referenced data base and appropriate applications software.

What is Georeferencing?

The process of delimiting a given object, either physical (eg. a lake) or conceptual (eg. an administrative region), in terms of its spatial relationship to the land; the geographic reference thus established consists of points, lines, areas or volumes defined in terms of some coordinate system (usually latitude and longitude, or UTM northings and eastings, and elevation). The background framework pertinent to geo-referencing includes: NTS and BCGS grids and related features.

What is Global Positioning System (GPS)?

A system of earth satellites, each providing precise time and position information which enables a GPS receiver to compute the distance to each satellite. The distance measurements of at least three satellites are required to fix the receivers position in latitude and longitude. Measurements from a fourth satellite are required to provide vertical (altitude) positioning.

What is map projection?

it is  the basic system of coordinates used to describe the spatial distribution of elements in a GIS

What is metadata (Data Description)?

Metadata is data about data. It typically includes information such as currency, accuracy, extent, custodianship, and collection methodology. Meta-data is typically stored in data models, dictionaries, schemas and other representations.

What is modeling in GIS?

It is the representation of the attributes of the earth Às surface in a digital database.

What is pixel (cell)?

Contraction of picture element; smallest unit of information in a grid cell map or scanner image.

What is precision?

A measure of the tendency of a set of random numbers to cluster about a number determined by the set. The usual measure is either the standard deviation with respect to the average ie., relates to the quality of the method by which the measurements were made and is distinguished from accuracy which relates to the quality of the result.

What is projection?

The representation on a plane surface of any part of the surface of the earth.

What is raster data?

A regular grid of cells covering an area.

What is Reference Ellipsoid?

An ellipsoid associated with a geodetic reference system or geodetic datum, whose surface is equi-potential and approximates the geoid in size and position. Reference ellipsoids are most commonly ellipsoids of revolution and are sometimes called reference spheroids.

What is Topology?

The way in which geographical elements are related to each other. The topology of the data must be defined before GIS analysis can be performed.

What is Vector Data?

it is the spatial representation of the feature locations using point, line and polygon (area).

What is zooming in/out?

A capability for proportionately enlarging or reducing the scale of a figure or maps displayed on a screen.