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Posted by ujaval@gmail.com on March 3, 2007, 4:16 am
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> > > I am building a Gis for road navigation When diplaying gthe poylines
> > > To clip According to me there are two ways;
> > > Which i have come about:
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> > > 1:) to clip the polylines in the world domain ie when they are still
> > > defined in terms of longitudes and latitudes.
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> > > 2:) To clip the polylines in the page domain that is after converting
> > > the polylines into the page cordinates(a Picture box)
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> > > I think the second way is better and efficient in my case as it will
> > > be more efficient because unessary points need not to be converted
> > > and
> > > as the i m going to see an area of about 60 * 60 meters usually
> > > (ususally the case with road navigation)
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> > > 1:) Can anyone tell me if im right or wrong??
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> > > 2:)How to clip in the world domain (im stuck how to get the
> > > intersection of the polyline with the clip rectangle
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> > i assume you are talking about clipping the file in real time for
> > display in road navigation. To answer your question, I think clipping
> > the vectors in real time and displaying them would be very inefficient
> > and result in bad user experience. You may create predefined tiles of
> > 60m x 60m and display them when required. You can use OGR library for
> > doing the clipping offline. (www.gdal.org)-Hide quoted text -
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> > - Show quoted text -
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> I needed to give a zoom facility what about that if i break it into
> slides 60 * 60 m
What program are you using to generate the image from the vector data?
If you can use Mapserver, all the zoom, tile generation, clipping
facilities are built in. If you are writing your own server, you can
decide predetermined zoom levels and generate the tiles. 30x30, 15x15
etc.
-ujaval
http://gisindia.blogspot.com
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