Raster data, also known as data grids, stores map data as matrices. Regular data grids require a referencing object, vector, or matrix that describes the sampling and location of the data points. Geolocated data grids explicitly identify the latitude and longitude coordinates of all rows and columns.
GeographicCellsReference | Reference raster cells to geographic coordinates |
GeographicPostingsReference | Reference raster postings to geographic coordinates |
MapCellsReference | Reference raster cells to map coordinates |
MapPostingsReference | Reference raster postings to map coordinates |
Raster geodata represents map data in matrix format.
Each element of georeferenced raster data corresponds to a defined quadrangle of territory on a planet.
Types of Data Grids and Raster Display Functions
You can display regular and geolocated data grids in many ways, such as a 2-D indexed image where color represents the data value, or as a 3-D surface with light shading.
Spatially Reference Imported Rasters
When you cannot import spatial referencing information using the
readgeoraster
function, you can manually reference the
raster instead.
Mosaic Spatially Referenced Raster Tiles
To analyze data spread across several raster tiles, first combine the tiles into a single raster.
This example shows how to store a matrix in a geographic referencing object. Display the matrix on a map, and specify display properties such as the projection, axes labels, and color map.
Precompute the Size of a Data Grid
This example shows how to compute the expected size of a large data grid, before creating the grid, to confirm that the grid will be manageable and will fit in memory.
Compute Gradient, Slope, and Aspect from Regular Data Grid
This example shows how to compute relationships between neighboring cells in a regular data grid.
A geolocated data grid is defined by three matrices giving latitude and longitude coordinates and indices associated with the mapped region.
Geographic Interpretations of Geolocated Grids
The dimensions of a map matrix and associated latitude and longitude matrices determines the interpretation of the geographic map data.
Compute Elevation Profile Along Straight Line
This example shows how to compute an elevation profile along a straight line by defining waypoints.
Display Shaded Relief Map Using Raster Data
This example shows how to generate a shaded relief map using geographic data in an array. You can change the displayed projection of the map without modifying the raster data.
Data Grids as Logical Variables
You can perform logic tests on data grid variables to create a binary logical grid.