[GRASSLIST:5447] Re: Newbie tries OS X port
Marvin Humphrey
marvin at rectangular.com
Sun Feb 2 20:54:18 EST 2003
On Saturday, February 1, 2003, at 07:23 PM, Glynn Clements wrote:
>> So the version of Tcl/Tk I got off the Apple site might not work, hmm?
>>
>> http://www.apple.com/downloads/macosx/unix_open_source/tcltk.html
>
> It might; the "unix_open_source" bit suggests that it may be either a
> Unix version or a hybrid Unix/Mac version, rather than a "pure" Mac
> version.
[snip]
> If Apple's Tcl/Tk package doesn't work, the "safe" solution is to
> download the Tcl/Tk source code and build it yourself (following the
> Unix build instructions).
So far, few things are going kablooey. Many of the modules I need
don't have GUIs anyway. I think I'll stick with the version I got from
Apple for now, unless I start uncovering more nasties...
> The TIFF format is extensible, and it's not uncommon for certain
> packages to add their own extensions (e.g. storing application
> settings in the image). Warnings regarding unknown extensions are
> usually harmless.
It's a sign of good programming that the GRASS doesn't choke on
unfamiliar fields in an extensible format. Kudos to both you and the
people who made that TIFF. (IME in audio, extensible formats are not
necessarily handled well...)
> That's OK for a test case. For real-world use, it usually needs to be
> the other way around; you have to move the imported map to its correct
> geographical location with r.region or r.support.
Very good. This is my next step.
>> A bonus would be to get locations of national and provincial
>> boundaries, major highways, etc, in some sort of vector format,
>> overlay
>> that so it syncs with the raster data, then export to DXF...
>> manipulate
>> raster data in Photoshop, MacDEM, or something similar, import the
>> nice
>> pretty raster file into Illustrator along with the DXF, shake well,
>> export to JPG, et voila! Hundreds of web maps for my client.
>>
>> Does anyone know of a source for such vector data?
>
> There are some links on the GRASS site. However, the quality of the
> data (in terms of what you end up with inside GRASS) can vary. Some of
> the proprietary formats have been implemented using a fair amount of
> trial-and-error.
I found national boundary files for the entire world from the CDC...
http://www.cdc.gov/epiinfo/EIshape.htm
http://www.cdc.gov/epiinfo/eihlgeog.htm
They're in .shp format -- I was able to get them to Illustrator through
a multistep process:
v.in.shape --> v.out.ascii --> v.export
Illustrator can grok a DXF file, so that's the magic inter-application
link. When I tried to skip the v.out.ascii step, GRASS hung during
v.export -- apparently it doesn't like trying to export an ascii file
from an internal binary format.
The resulting DXF output appeared to line up well in Illustrator with
the GTOPO30, so I suppose they're using the same equidistant
cylindrical projection.
There's a zillion sources for this data, and a zillion formats! Maybe
if I'm lucky I can find another source that has highways and cities as
well as political boundaries...
-- Marvin Humphrey
CD Design website: http://marvin.mrtoads.com
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