Landmass avoidance using island about cdt HOT 5 OPEN

How can I modify the land_mask.mat matrix and add these sub-sea construction coordinates to that matrix ?

Should I use a load function to call this matrix from the Toolbox in the main file? Or do you suggest me to copy the island.m function as well as land_mask.mat to the working folder and modify the logical matrix from there?

Thank you for reading my question

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Would you recommend me with this procedure:

• Download the DEM from http://srtm.csi.cgiar.org/srtmdata/
• Read each GeoTIFF image using geoimread
• Run loop if it is grey scale (A value = -32768) then landmask matrix value = 0
• Merge landmask matrix

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The mask isn't a very high resolution grid, so I'm not sure how valuable it will be for ship navigation. However, to customize the mask from another GeoTIFF I'd use interp2, or from a polygon use inpolygon.

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Thank you for your details reply, I will use your suggestion then

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Hi Chad, thank you so much for your recommendation.

I used georead to convert the geotiff and save the coordinate as well as the is_land matrix to -v7.3 MAT-file. The uncompressed file is 10GB per file and the whole world contains 48 file of this. I am using interp2 to read 3 lon and lat from same matrix but this process took 189 seconds to run.

Using a SSD, loading the mat file took only 35 seconds but interpolation took the 159 seconds rest for 3 coordinate. Would you recommend any other faster method beside interp2?

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