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Plotting grey scale images.

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suchitra rani
suchitra rani on 22 Aug 2019
Commented: Rik on 22 Aug 2019
Hello ,
I am trying to plot grey scale images of size 631 x 661 having negative values ranging from -21.35 to -13.26.After reading the image ,it shows black pixels unless [] are given.I want to plot geoshow command.How can i do it. I tried geoshow command but it gives images of black pixels ..
I=imread('GBGEO.tif') ;
VV=I(:,:,2);
imshow(VV,[]).
geoshow(lat,long,VV)

  1 Comment

Rik
Rik on 22 Aug 2019
Most function will assume images of type double have a data range of [0 1], unless you tell them otherwise. The documentation for geoshow is a bit unclear about this, but it seems to follow the same convention.
You should rescale your data to whatever you're expecting to be the data range. Using [] with imshow implicitly rescales your data to [0 1], so like this:
data=(data-min(data(:)))/(max(data(:))-min(data(:)));
(actually it sets the caxis instead of changing your data)

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