georesample

Resample geographic raster

Since R2025a

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    Syntax

    B = georesample(A,RA,RB)
    B = georesample(A,RA,RB,method)

    Description

    B = georesample(A,RA,RB) resamples the geographic raster A, which uses the raster reference RA, so that the output geographic raster B is referenced to the target raster reference RB.

    example

    B = georesample(A,RA,RB,method) specifies the interpolation method. By default, the function uses linear interpolation.

    example

    Examples

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    Open Live Script

    Read raster data into the workspace as an array and a geographic postings reference object. The array is of size 1201-by-1201.

    [A,RA] = readgeoraster("n40_w106_3arc_v2.dt1",OutputType="double");

    Create the target reference object by making a copy of the original reference object. Specify a new raster size by changing the RasterSize property of the target reference object.

    RB = RA;
RB.RasterSize = [701 701];

    Resample the raster data. The resampled array is of size 701-by-701. 

    B = georesample(A,RA,RB);
    Open Live Script

    Read raster data into the workspace as an array and a geographic postings reference object. The raster has latitude limits in the range [40, 41] and longitude limits in the range [–106, –105].

    [A,RA] = readgeoraster("n40_w106_3arc_v2.dt1",OutputType="double");

    Create the target reference object by making a copy of the original reference object. Specify new latitude and longitude limits by changing the LatitudeLimits and LongitudeLimits properties of the target reference object.

    RB = RA;
RB.LatitudeLimits = [40 40.5];
RB.LongitudeLimits = [-106 -105.5];

    Resample the raster data.

    B = georesample(A,RA,RB);
    Open Live Script

    Read elevation data from two files into the workspace. The files contain data for the same area of interest.

    • n40_w106_3arc_v2.dt1 contains medium-resolution data, with posting point samples every 3 arc seconds.

    • w106/n40.dt0 contains coarse-resolution data, with posting point samples every 30 arc seconds. 

    [A1,R1] = readgeoraster("n40_w106_3arc_v2.dt1",OutputType="double");
[A2,R2] = readgeoraster("w106/n40.dt0",OutputType="double");

    Verify that the data sets use the same type of coordinate system.

    isequal(R1.CoordinateSystemType,R2.CoordinateSystemType)
    ans = logical
   1

    Verify that the data sets use the same geographic coordinate reference system. 

    isequal(R1.GeographicCRS,R2.GeographicCRS)
    ans = logical
   1

    Resample the medium-resolution data to match the resolution of the coarse-resolution data.

    resampledA1 = georesample(A1,R1,R2);

    Note that the resampled array and the coarse-resolution array have the same size. 

    whos resampledA1 A2
      Name               Size              Bytes  Class     Attributes

  A2               121x121            117128  double              
  resampledA1      121x121            117128  double
    Open Live Script

    Read raster data into the workspace as an array and a geographic postings reference object. The array is of size 1201-by-1201.

    [A,RA] = readgeoraster("n40_w106_3arc_v2.dt1",OutputType="double");

    Create the target reference object by copying the original reference object and changing the raster size.

    RB = RA;
RB.RasterSize = [1501 1501];

    Resample the raster using the cubic interpolation method. 

    B = georesample(A,RA,RB,"cubic");

    Input Arguments

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    Geographic raster, specified as an M-by-N or M-by-N-by-P numeric or logical array.

    Raster reference for A, specified as a GeographicCellsReference object or GeographicPostingsReference object.

    The GeographicCRS properties of RA and RB must be equal, unless one of the GeographicCRS properties is empty.

    Target raster reference, specified as a GeographicCellsReference object or GeographicPostingsReference object. The resampled raster B is referenced to RB.

    The GeographicCRS properties of RA and RB must be equal, unless one of the GeographicCRS properties is empty.

    Interpolation method, specified as one of these options:

    • "linear" — Linear interpolation. The interpolated value at a query point is based on linear interpolation of the values at neighboring points. This method is sometimes called bilinear interpolation.

    • "nearest" — Nearest-neighbor interpolation. The interpolated value at a query point is the value of the nearest point. This method is useful for resampling indexed images.

    • "cubic" — Cubic interpolation. The interpolated value at a query point is based on cubic interpolation of the values at neighboring points. This method is sometimes called bicubic interpolation.

    Output Arguments

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    Resampled geographic raster, returned as a numeric or logical array. B is referenced to the target raster reference RB. The data type of B matches the data type of A.

    Elements of the resampled raster that are outside the area defined by the original raster depend on the data type of B:

    • When B uses the single or double data type, the elements are NaN values.

    • When B uses an integer or logical data type, the elements are 0 values.

    Tips

    • To resample a raster in planar map coordinates, use the mapresample function.

    • To perform antialiasing when shrinking a raster, use the georesize function.

    Version History

    Introduced in R2025a

    See Also

    Functions

    Objects