GIS - Maps & Statistics Flashcards
Datum
In surveying and geodesy, a datum is a set of reference points on the earth’s surface against which position measurements are made, and (often) an associated model of the shape of the earth (reference ellipsoid) to define a geographic coordinate system.
Mean
The mean (average) of a data set
median
the median is the middle value when a data set is ordered from least to greatest.
mode
The mode is the number that occurs most often in a data set.
Management Information Systems (MIS)
Management Information Systems (MIS) is the study of people, technology, organizations, and the relationships among them.
b2b
Business-to-business is a situation where one business makes a commercial transaction with another.
geographic information system (gis)
A geographic information system is a conceptualized framework that provides the ability to capture and analyze spatial and geographic data.
polygon
When GIS software is used to draw the outline of a lake on a map, the resulting shape is known as a polygon. The term ‘area’ is also used sometimes, instead of polygon. A polygon is one of three feature types – others are line and point – with which almost all spatial data is depicted in GIS.
node
In a geodatabase, the point representing the beginning or ending point of an edge, topologically linked to all the edges that meet there.
attribute
A. attribute. [data models] Nonspatial information about a geographic feature in a GIS, usually stored in a table and linked to the feature by a unique identifier. For example, attributes of a river might include its name, length, and sediment load at a gauging station.
elevation
Elevation is distance above sea level. Elevations are usually measured in meters or feet. They can be shown on maps by contour lines, which connect points with the same elevation; by bands of color; or by numbers giving the exact elevations of particular points on the Earths surface.
vector & raster
The old GIS adage “raster is faster, but vector is corrector”
comes from the two different fundamental GIS models:
vector and raster. Each of these models has its own
advantages and disadvantages. The vector model uses
points and line segments to identify locations on the earth
while the raster model uses a series of cells to represent
locations on the earth. T
1 yard = ? feet
3 feet
resolution
The scale of a map is the ratio of a distance on the map to the corresponding distance on the ground.
projections & types
A projection is the means by which you display the coordinate system and your data on a flat surface, such as a piece of paper or a digital screen. Mathematical calculations are used to convert the coordinate system used on the curved surface of earth to one for a flat surface. 4 types- Conic, cylindrical, planar, polar
datum (world vs. 1983)
The North American 1983 datum (NAD83) uses the Geodetic Reference System (GRS80) ellipsoid while the World Geodetic System of 1984 (WGS84) uses the WGS 84 ellipsoid. The dimensions of these ellipsoids differ slightly.
CAD
Computer-aided design is the use of computers to aid in the creation, modification, analysis, or optimization of a design. CAD software is used to increase the productivity of the designer, improve the quality of design, improve communications through documentation, and to create a database for manufacturing.
Ian mcCard
almost father of GIS layers
Geocoding
Geocoding is the process of transforming a description of a location—such as a pair of coordinates, an address, or a name of a place—to a location on the earth’s surface. You can geocode by entering one location description at a time or by providing many of them at once in a table.
Georeferencing
Georeferencing is the name given to the process of transforming a scanned map or aerial photograph so it appears “in place” in GIS. By associating features on the scanned image with real world x and y coordinates, the software can progressively warp the image so it fits to other spatial datasets.
Registering
Data registration provides the server with a list of locations for your web services’ source data. Data registration helps you validate that your services will reference data locations known and approved by the server administrator.
Land based Classification System (zoning)
colors - yellow = residential; red =commercial
type of GIS analysis
site, economic, environmental, trend analysis
Triangular Irregular Networks (TIN modeling)
Triangular irregular networks (TIN) have been used by the GIS community for many years and are a digital means to represent surface morphology. TINs are a form of VECTOR-based digital geographic data and are constructed by triangulating a set of vertices (points).
metes and bounds
Metes and bounds are the boundaries of a parcel of real estate that identified by its natural landmarks. Metes and Bounds landmarks are often used in a “legal description” of a land.