Raster Data

Georeference, analyze and transform gridded data

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.

Functions

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Geographic Rasters

Reference Objects and Latitude-Longitude Grids

`georefcells`	Reference raster cells to geographic coordinates
`georefpostings`	Reference raster postings to geographic coordinates
`refmatToGeoRasterReference`	Convert referencing matrix to geographic raster reference object
`refvecToGeoRasterReference`	Convert referencing vector to geographic raster reference object
`geoloc2grid`	Convert geolocated data array to regular data grid

Analyze and Manipulate Data

`georesize`	Resize geographic raster
`geocrop`	Crop geographic raster
`geointerp`	Geographic raster interpolation
`contains`	Determine if geographic or map raster contains points
`geopeaks`	Generate synthetic data set on sphere
`imbedm`	Encode data points into regular data grid
`filterm`	Filter latitudes and longitudes based on underlying data grid
`findm`	Latitudes and longitudes of nonzero data grid elements
`changem`	Replace values in array
`encodem`	Fill in regular data grid from seed values and locations

Planar Map Rasters

Reference Objects

`maprefcells`	Reference raster cells to map coordinates
`maprefpostings`	Reference raster postings to map coordinates
`refmatToMapRasterReference`	Convert referencing matrix to map raster reference object

Analyze and Manipulate Data

`mapresize`	Resize projected raster
`mapcrop`	Crop projected map raster
`mapinterp`	Map raster interpolation
`contains`	Determine if geographic or map raster contains points
`mapoutline`	Compute outline of georeferenced image or data grid
`changem`	Replace values in array
`encodem`	Fill in regular data grid from seed values and locations

World File Matrices

`georasterref`	(Not recommended) Create geographic raster reference object
`maprasterref`	(Not recommended) Create map raster reference object
`refmatToWorldFileMatrix`	Convert referencing matrix to world file matrix

Objects

`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

Topics

Introduction to Geodata in Raster Format

Raster Geodata
Raster geodata represents map data in matrix format.
Georeferenced Raster Data
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.

Regular Data Grids

Construct a Global Data Grid
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.

Geolocated Data Grids

Geolocated Data Grids
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.

Applications of Gridded Geodata

Data Grids as Logical Variables
You can perform logic tests on data grid variables to create a binary logical grid.

Featured Examples

Combine Dissimilar Grids by Converting Regular Grid to Geolocated Data Grid

Combine an elevation data grid and an attribute data grid that cover the same region but are gridded differently.

Open Live Script

Georeferencing an Image to an Orthotile Base Layer

Register an image to an earth coordinate system and create a new georeferenced image (requires Image Processing Toolbox™).

Open Script

Unprojecting a Digital Elevation Model (DEM)

How to convert a USGS DEM into a regular latitude-longitude grid having comparable spatial resolution.

Open Script