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latlon2pix

(To be removed) Convert latitude-longitude coordinates to pixel coordinates

The latlon2pix function will be removed in a future release. Use the geographicToIntrinsic function instead. For more information, see Compatibility Considerations.

Syntax

[row, col ] = latlon2pix(R,lat,lon)

Description

[row, col ] = latlon2pix(R,lat,lon) calculates pixel coordinates row, col from latitude-longitude coordinates lat, lon. R is either a 3-by-2 referencing matrix that transforms intrinsic pixel coordinates to geographic coordinates, or a geographic raster reference object. lat and lon are vectors or arrays of matching size. The outputs row and col have the same size as lat and lon. lat and lon must be in degrees.

Longitude wrapping is handled in the following way: Results are invariant under the substitution lon = lon +/- n * 360 where n is an integer. Any point on the Earth that is included in the image or gridded data set corresponding to r will yield row/column values between 0.5 and 0.5 + the image height/width, regardless of what longitude convention is used.

Examples

Find the pixel coordinates of the upper left and lower right outer corners of a 2-by-2 degree gridded data set.

R = georefcells([-90 90],[0 360],2,2,'ColumnsStartFrom','north')
[UL_row, UL_col] = latlon2pix(R,  90, 0)     % Upper left
[LR_row, LR_col] = latlon2pix(R, -90, 360)   % Lower right

Version History

Introduced before R2006a

expand all

R2023a: Warns

Some functions that accept referencing matrices as input issue a warning that they will be removed in a future release, including the latlon2pix function. Use a geographic raster reference object and the geographicToIntrinsic function instead. Reference objects have several advantages over referencing matrices.

  • Unlike referencing matrices, reference objects have properties that document the size of the associated raster, its geographic limits, and the direction of its rows and columns. For more information about reference object properties, see the GeographicCellsReference and GeographicPostingsReference objects.

  • You can manipulate the limits of rasters associated with reference objects using the geocrop function.

  • You can manipulate the size and resolution of rasters associated with reference objects using the georesize function.

  • Most functions that accept referencing matrices as inputs also accept reference objects.

To update your code, first create a reference object for either a raster of cells using the georefcells function or a raster of regularly posted samples using the georefpostings function. Alternatively, convert from a referencing matrix to a reference object using the refmatToGeoRasterReference function.

Then, replace uses of the latlon2pix function with the geographicToIntrinsic function according to this pattern.

Will Be RemovedRecommended
[row,col] = latlon2pix(R,lat,lon);
[col,row] = geographicToIntrinsic(R,lat,lon)