How to change land data to NaN?
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Hi,
I have plotted a bathymetry and now I'm given coastline and some islands files where I need to use them to define where the land is and then turn the land data to NaN.
How should I do that?
Thanks, Eve
4 个评论
Geoff Hayes
2014-10-29
Eve - how do you (currently) calculate the volume? What information do you use for that?
回答(2 个)
Kelly Kearney
2014-10-27
The inpolygon function will do most of the work. Depending on the scale of your region and the format of the coastlines, you may need to close off polygons, reverse order of vertices, and upsample polygons in order to get the best results; the Mapping Toolbox has several functions ( flatearthpoly, interpm, ispolycw, poly2cw) to help with that.
6 个评论
Kelly Kearney
2014-10-31
Can you upload the coastline file? The answer will depend on whether it contains just the visible line segments you plotted above, or fully-closed polygons. Assuming it's the latter, your code to mask the land points will look something like:
isin = inpolygon(xi, yi, xcoast, ycoast);
zi_diff(isin) = NaN;
But you may need to do some processing of xcoast and ycoast to convert them to closed, clockwise polygons.
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