| Re: Land Mask data set available? (in lat and lon) [message #29171] |
Thu, 07 February 2002 14:47  |
Mark Hadfield
Messages: 783
Registered: May 1995
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Senior Member |
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"Robert Stockwell" <stockwell@co-ra.com> wrote in message
news:3C62F3C6.3090502@co-ra.com...
> ...
> I was just about to assimilate the land mask info
> into IDL, but for my purposes I need the land mask
> as a function of lat and lon (so as to branch my
> algorithm on whether or not a data point falls on land),
> rather then merely an image.
> ...
> I am about to use the land=sea mask data from:
> http://edcdaac.usgs.gov/1KM/land_sea_mask.html
> that i found snooping through google. It looks like
> I'll have to grab their image which appears to be in
> a km by km sampling, and calculate the inverse transform
> from their map projection into lat and lon (ugh).
> ...
> Does someone have that in IDL?
> (or rather, a data format that can be easily digested
> into IDL)
Thanks for the link to the land-sea mask data. I wasn't aware of that one. I
agree that it might be awkward inverting their map projection. There's been
some discussion on the group in the past about accessing IDL's built-in
projections. A Google search might turn up something useful.
I don't have a land-mask data set, but I do have a routine that calculates a
land mask (in fact a land fraction) for a specified grid using vector
shoreline data from the GSHHS data set:
http://www.ngdc.noaa.gov/mgg/shorelines/gshhs.html
Getting this working on your system would be non-trivial, but if you want to
try I'll be glad to help.
---
Mark Hadfield
m.hadfield@niwa.co.nz http://katipo.niwa.co.nz/~hadfield
National Institute for Water and Atmospheric Research
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