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Example Map Produced with GMT

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#1
dylan

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Here is a quick example of a map produced with the Generic Mapping Tools. Data was projected to an Albers Conic projection and plotted with the open source GMT tools.

Some additional information on how this map was produced can be found here.

Dylan

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#2
woneil

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Very neat and impressive. Certainly raises my interest level in GMT. Now if I can only figure out how to get it on my Win 2000 system...

Thanks,
Will O'Neil
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Author and amateur cartographer

http://analysis.williamdoneil.com/w.d.oneil@pobox.com

#3
dylan

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Now if I can only figure out how to get it on my Win 2000 system...

<{POST_SNAPBACK}>


There is a native Windows binary install. From the chatter on the mailing list, it appears as if many people are using the Windows version.
Good luck!

Dylan

#4
Rob

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dylan,

nice to see that post and a great use of GMT. I have only used the unix version but really liked it for the flexibility to do some many different opperations from a small and free package.

For those looking for a free, highly developed, robust tool to move data quickly into a map, especially in an lab/science setting, this is a very productive (and free) start. I've noticed that many cart graphics in science journals look like they've used GMT. I also think it's a good tool to teach GIS to students without the point/click mentality of some other packages.

rob

#5
Kartograph

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Q for all GMT users:
Where does the data come from? I recently helped out a friend of mine, who is a mathematician. He had to auto generate maps, so he used gmt. But he couldn´t tell me, where he got the geodata from. Which data formats can it handle?

Thanks in advance,

Andreas

#6
dylan

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Q for all GMT users:
Where does the data come from? I recently helped out a friend of mine, who is a mathematician. He had to auto generate maps, so he used gmt. But he couldn´t tell me, where he got the geodata from. Which data formats can it handle?

Thanks in advance,

Andreas

<{POST_SNAPBACK}>



A simple answer would be: "Where all data comes from- GMT can use any sort of input."

A better answer would be:

For the shorline/political bounds/water bodies/ect. the GSHHS is used. This provides a multi-scale linework for most small scale maps produced with GMT.

For the map that I submitted below, a couple datasources were used:
1. the California topography layer was downloaded from the Ca GIS page. This data had to be inverse-projected back to lat-long, and have some holes filled. The inverse projection was done with GDAL, and the fixing of errors was done with GRASS. This file was essentially a pre-made hillshade, derived from generalized elevation data. GMT has the ability to generate a hillshade directly from raw elevation data as well.

2. The state and county lines were derrived from shapefiles, also from the Ca GIS page. They too were inverse-projected to lat/long and converted to a GMT-friendly text format. The conversion of shapefiles to GMT-style can be done with a freely available <i>shp2gmt</i>.

3.The point data was plotted from a simple text file of lat/long pairs, directly dumped from my GPS.

Summary: The data can come from nearly anywhere, but it usually must first be converted to a GMT-friendly format (i.e. NetCDF or ascii text). Also, the data may come in projected or un-projected coordinates, however all data within a single map should be in the same projection. If the input data are in lat/long, GMT will project it all to the coordinate system defined when plotting the data- as was the case of my example map.

Cheers,

#7
Kartograph

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I see.

So it´s GSHHS for the base data. At least for my friend. I had to generate ascii files for him, so now everything comes together :) .
Thanks fo your input,

Andreas




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