[OSRS-PROJ] orthographic projection with proj4 and mapserver.

[Judd Taylor]

Wow! Thanks for all of the help.

With the GSHHS code that was mentioned earlier in the thread, there is a bit
of code to decimate the polygons to lower resolutions, and also a program to
convert the dataset to GRASS format. The dataset doesn't include political
boundries, just coastlines.

For my maps, I need the full resolution data set, since my areas are small
(florida keys for instance), but the polygons (closed figures) are setup in
the files as continuous coastlines, ie, the coastline for the mainland of
florida is part of the polygon that includes all of North America (and maybe
South Am as well).

Most of my attempts to just ignore most of the data points that are outside
of my map area don't work b/c some of the more complicated clipping issues
on some maps (one that usually fails my attempts shows part of florida in
the top, part of cuba, and part of the yucatan in the bottom, which is the
same polygon as florida...).

Here are some of the maps I'm producing now:
http://modis.marine.usf.edu/products/flbay/rgb/MODIS.2003225.162301.flbay.rgb.png
http://modis.marine.usf.edu/products/seacoos/chl/MODIS.2003225.174927.seacoos.chlor_MODIS.png

I'd be very interested in any algorithms like Norman described  that clip
the main polygons into areas, without showing the boundries between areas.
Any links/examples?

Thanks again,
    Judd Taylor


----- Original Message ----- 
From: "Norman Vine" <nhv at cape.com>
To: <osrs-proj at remotesensing.org>
Sent: Thursday, August 14, 2003 11:45 AM
Subject: RE: [OSRS-PROJ] orthographic projection with proj4 and mapserver.


> Gerald I. Evenden writes:
> >
> > 3. Anyone know of current "erosion" programs?  Programs that remove
> > points from a coastline file based on the complexity of the
> > coastline itself.  15 years ago I had a couple of reasonable
> > procedures but have since lost them.
>
> This is a classic
> http://www.cs.sunysb.edu/~algorith/implement/DPsimp/implement.shtml
>
> HTH
>
> Norman
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