[OSRS-PROJ] Re: Orthographic Projections and MapServer

Steve Lime steve.lime at dnr.state.mn.us
Sat Aug 23 00:03:24 EDT 2003

I'd also be glad to help with details on internals, rendering engine and
so on. Just let me know what you need. We appreciate the help!


>>> warmerdam at pobox.com 08/22/03 9:17 PM >>>
Gerald I. Evenden wrote:
> I have looked at portions of the MapServer code and I am fairly
> comfortable with the style.  But, and a big but, I am not familiar
> with:
> 1. the overall flow,
> 2. the graphic engine it uses
> 3. and working in the networking environment.
> If it can function on a stand alone system then I think I can work on
> it and leave network testing for someone else.
> I did run configure and determined that I need to plug a couple of
> packages into my system and modify the code to link to libproj4
> (this looks easy).  I think I have all the stuff on my source
> distribution DVD.  But I will have to download a couple of items
> from OSRS-PROJ.


You shouldn't need to many other packages other than GD.  You can do
without GDAL if you just want to do shapefile to PNG.  I can provide
the world shapefile dataset and a .map file demonstrating the
problem.  You can also use mapserver in "command line" form, which I do
for most of my testing.  So for instance, something like:

shp2img -m test.map -o out.png

Easy to debug though it then, no network interaction then.

For working on the code, I would suggest you implement an
msProjectShapeWithClipping() function in mapproject.c to the
same API as msProjectShape() or something to that effect.   The
msProjectShape() function is called for all reprojections of points,
lines and areas.  If you investigate the shapeObj closely you should
be able to see how the different geometry types are handled.

> I do note one problem, configure looks for GD 2.0.12 or higher
> and I only have 2.0.9 on a 2003 distribution disk.  Hmmmm.
> Have to google around and find the home for this package.

GD can be found at:

> I wish this package output to PostScript so it would be useful
> for Hi-res hard copy like pdf.

There is support for output to pdf format (and flash) but I
don't know how good the quality of this rendering engine is.  The
"gd" renderer is most widely used.  If you want pdf support you
will need to configure and link with pdflib.

> Looks like a few days just to install this thing and several
> more learning how to use it.  Modifying it is another story.
> If someone is willing to be bugged a few times a day for about
> a week, I would give it a try.

I would be happy to answer any questions.

Best regards,
I set the clouds in motion - turn up   | Frank Warmerdam,
warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent

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