A discretely uniform unit that represents a portion of the Earth. such as a square meter or square mile. Each grid cell has a value that corresponds to the feature or characteristic at that site, such as a soil type, census tract, or vegetation class. See also Cell.
grid cell -- a two-dimensional object that represents the smallest nondivisible element of a grid.
Grid Cell Map
Map displaying spatial information in the form of color coded, equal sized rectangle, squares, equilateral triangles or hexagons. The color of the cell determined by the condition assigned to the cell according to a uniformly applied rule regarding the condition (i.e.
Grid Cell - An element of a raster data structure (see raster).
GUI - See Graphical User Interface.
e.g. grid cells covering large areas
historically, natural resource GIS have been raster-based
adequate for many planning and management applications
can provide comprehensive coverage of a jurisdiction at reasonable cost
could often run on existing mainframes - hardware requirements were modest ...
Output grid cell color values represent stocking levels (Blue = good, Green = medium, Red = poor, White = nonstocked). A) Initial stocking grid calculated from successful germinants. B) General stocking regions as determined by focal functions application.
Figure 4 - ...
Rectification typically involves rotation and scaling of grid cells, and thus requires resmapling of values. Relate An operation establishing a connection between corresponding records in two tables using an item common to both.
A GIS database includes data about the spatial location and shape of geographic features recorded as points, lines, areas, pixels, grid cells, or tins, as well as their attributes. database design The formal process of analyzing facts about the real world into a structured database model.
In geoprocessing, raster refers to a digital representation of the extent of geographic data sets using "grid cells" in a matrix. A raster display builds an image from pixels, small square picture elements of coarse or fine resolution.
a map, which does specifically define the location of each name or code number involved. Four types of location identifiers are used: a) Points - as abstractions of small phenomena or surrogates for larger phenomena, b) Line segments - for linear feature, c) Arbitrary regular area - grid cells, ...
The value in each grid cell is the number of flowlines which pass through that grid cell, that means the number of flowlines from the entire map which have segment endpoints within that cell. With the -m flag less memory is used as aspect at each cell is computed on the fly.
Furthermore, if no data are present for a given pixel, a data value placeholder must be assigned to this grid cell. Often, an arbitrary, readily identifiable value (e.g., −9999) will be assigned to pixels for which there is no data value.
Raster Data Structures consist of an array of grid cells or pixels referenced by a row and column number and containing a number representing the type or value of the attribute being mapped.
To 19971029 Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Raster Raster_Object_Information: Raster_Object_Type: Grid Cell Row_Count: 1400 Column_Count: 959 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Grid_Coordinate_System: ...
Cellular automata imposes a fixed spatial framework such as grid cells and specifies rules that dictate the state of a cell based on the states of its neighboring cells.
The example on the left shows the 1992 time stamp of the change in the percentage of cropland (per grid cell) worldwide from 1700 to 1992 in ArcMap. When visualized over time, the percentage of cropland in some areas increases as time passes.
Each grid cell needs to have a Region of Influence (R-of-I) value. A database table is created by //Spatial that contains the grid cell identifiers (usually row and column numbers), and all the aggregate behavior data, travel-time values, etc., from each of the grid maps in the spatial database.
Raster displays and databases build all geographic features from grid cells in a matrix. A raster display builds an image from pixels, pels, or elements of coarse or fine resolution.
The procedure for locating and translating geographic coordinates in x,y digits or grid cells for an object or event in space and coded in map units, lines, and points.
For example, in the case of Sydney, Australia, its UTM grid cell (zone) would be identified as:
H - for the latitudinal zone it belongs to
56 - for the longitudinal zone it belongs to
Add the two together - the UTM grid zone (grid cell) which contains Sydney is 56H ...
In practice the area under study is covered by a fine mesh, or matrix, of grid cells and the particular ground surface attribute value of interest occurring at the centre of each cell point is recorded as the value for that cell.
Many grid operations are directly proportional to the number of grid cells, so this also will quadruple computation times. Hence, using a very small cell size can have a disproportionate effect on disk storage needs and on computation time.
The basic element in a raster based format (grids). Grid cells are always square.
Extraction of features present in one coverage as defined (spatially) by bounding features of a clip coverage.
Pixel: One picture element. Often used synonymously with a raster or grid cell. The smallest discrete element which makes up an image.
Planimetric: In mapping, refers to spatial data that do not include topographic or relief data.
A raster image comprises a collection of grid cells rather like a scanned map or picture. Both the vector and raster models for storing geographic data have unique advantages and disadvantages. Modern GISs are able to handle both models.
Raster - A data structure that is based on the use of grid cells. See also Tessellation and Vector.
TO set up the Grid, we have to bring up the Window Setup Dialog (under the Window menu) to adjust the major and minor grid cell size. For the baseball field, it will be useful to set the module to 50' with 5 grid divisions per module.
Grid: A geographic data model representing information as an array of equally sized square cells arranged in rows and columns. Each grid cell is referenced by its geographic x,y location.
The definition of the features is dependent upon the size of the individual grid cells - the resolution. The vector data is more like a graph with a line drawn between points, the width staying the same however close you zoom.
A logical collection of interrelated information, managed and stored as a unit, usually on some form of mass-storage system such as magnetic tape or disk. A GIS database includes data about the spatial location and shape of geographic features recorded as points, lines, areas, pixels, grid cells, ...
Each cell stores a numeric value that represents a geographic attribute (such as elevation) for that unit of space. When the grid is drawn as a map, cells are assigned colors according to their numeric values. Each grid cell is referenced by its x,y coordinate location.
Each point feature is represented as a single coordinate pair, while line and polygon features are represented as ordered lists of vertices. Attributes are associated with each vector feature, as opposed to a raster data model, which associates attributes with grid cells.
A simple database might be a single file with many records, each of which references the same set of fields. A GIS database includes data about the spatial locations and shapes of geographic features recorded as points, lines, areas, pixels, grid cells, or TINs, as well as their attributes.
Information obtained from image sources such as remote sensing from photography and satellite. Raster data thus refers to data in the form of parallel scan-line segments, grid cells or pixels. Also known as Cell System or Grid System.
with a grid of 100 numbered cells, proposed as an aid for quickly locating points in addition to the ordinary latitude/longitude coordinate system. Antarctica is interrupted, but this inconvenience can be alleviated by an inset, by a second map with hemispheres swapped, or by moving three grid cells ...
65 a spatial data model based upon a regular tessellation of a surface into pixels or grid cells. ratio p. 12 a level of measurement that includes both extensive and derived measurements. The numerical values of the measurement have a meaningful zero reference and a fixed unit of measure.
See also: Grid, Information, Geographic, Location, Model