mapshow - I can't seem to plot a geoTIFF

I'm trying to plot a geoTIFF image using mapshow. The file seems fine.

>> georasterinfo(filename)

ans = 

RasterInfo with properties:

Filename: "/home/seisan/STUFF/data/geographic/SRC-GIS/Montserrat/dem/dem_2014_SHV_3m_hs.tif"
FileModifiedDate: 2023-03-23 10:35:44
FileSize: 10425084
FileFormat: "GeoTIFF"
RasterSize: [3495 3842]
NumBands: 1
NativeFormat: "int16"
MissingDataIndicator: 32767
Categories: []
ColorType: "grayscale"
Colormap: []
RasterReference: [1×1 map.rasterref.GeographicCellsReference]
CoordinateReferenceSystem: [1×1 geocrs]
Metadata: [1×1 struct]

And the file seems good.

>> [I, R] = readgeoraster(filename);
>> R

R = 

GeographicCellsReference with properties:

LatitudeLimits: [16.6717577921979 16.7686941613068]
LongitudeLimits: [-62.2455721182769 -62.1390114515769]
RasterSize: [3495 3842]
RasterInterpretation: 'cells'
ColumnsStartFrom: 'north'
RowsStartFrom: 'west'
CellExtentInLatitude: 2.77357279281686e-05
CellExtentInLongitude: 2.77357279281675e-05
RasterExtentInLatitude: 0.0969363691089491
RasterExtentInLongitude: 0.10656066670002
XIntrinsicLimits: [0.5 3842.5]
YIntrinsicLimits: [0.5 3495.5]
CoordinateSystemType: 'geographic'
GeographicCRS: [1×1 geocrs]
AngleUnit: 'degree'

But mapshow gives the following error, after I convert the int16 values to uint16.

>> mapshow( uint16(I), R )
Error using checkRefObj
Function mapshow expected input number 2, R, to be either a 3-by-2 referencing matrix or a scalar map raster reference object.
Instead its type was: map.rasterref.GeographicCellsReference.

Error in validateMapRasterData>parseImageInputs (line 112)
refmat = checkRefObj(mapfcnname, R, size(A), R_position);

Error in validateMapRasterData>validateImageComponent (line 92)
[A, R] = parseImageInputs(mapfcnname, dataArgs{:}, cmap, rules );

Error in validateMapRasterData (line 26)
[Z, SpatialRef] =  validateImageComponent(mapfcnname, ...
    
Error in maprastershow (line 132)
validateMapRasterData('mapshow', dataArgs,  displayType, HGpairs);

Error in mapshow (line 246)
h = showFcn(varargin{:});

What am i doing wrong?

Unfortunately, I can't share the geoTIFF file publicly.

Answer 1

[Cris LaPierre]

Your variable R is a GeographicCellsReference object. However, mapshow specifies that R must be either a MapCellsReference or MapPostingsReference or GeographicPostingsReference map raster reference object, or a 3x2 matrix.

I do not believe a utility exists yet to convert between these grids (see here).

Try using geoshow instead.

[dormant]

Many thanks. I managed to plot it using imshow, but it required a lot of fiddling to get it georeferenced and (especially) to plot data on top of it.