[OpenLayers-Users] Orthorectifying

[Linda Rawson]

I think I can get this one but if someone has a formula to help me that
would be great.

Basically he uses the panning tool.  The north, south, east, west tool.  So
when he goes east he does not want to evenly go to the next square.  He
wants to go to the next square based on a sphere.  If he was on the equator
then the pixels would be correct.  But if he is in say Canada he wants to
panning tool to go to the next square in the sphere.  I hope this is making
sense.

I create the image based on the lat/lon coordinates passed to me with open
layers.  The mapping service I use just needs the upper left and lower right
corners to return the images.

Thanks for clarifying the term for me.  I am a software developer who is
trying to understand the GIS world.  You guys are great!

Linda Rawson


On 9/28/07, Paul Ramsey <pramsey at refractions.net> wrote:
>
> Linda,
>
> Your customer's understanding of "orthorectification" is completely
> wrong (it is a process for taking raw images from planes and
> satellites, and making it map-ready, so that every part of the image
> appears as if view from nadir). So let's ignore the term for now.
>
> Your explanation of what you are doing to get your images, and what
> your customer thinks you are doing wrong, are not clear to me.  Could
> you be a little more detailed about how you are making images for
> openlayers, first of all?
>
> P
>
> On 28-Sep-07, at 2:26 PM, Linda Rawson wrote:
>
> > The map provider I get images from does not have a WMS service.  I
> > have tried to get tilecache to run on IIS and was never
> > successful.  Hence I am grabbing the lat/lon coordinates returned
> > by openlayers creating a single tile and then presenting the image
> > to the user.
> >
> > My customer says the following:
> >
> > Looking at the header info on some images downloaded today it
> > appears you are navigating along a lat lon grid as if it were
> > orthogonal. Unfortunately this doesn't work with the imagery as
> > served by the map providers. they "orthorectify" the images so the
> > tiles are in a Cartesian space rather than a spherical space. The
> > means when you move straight east or straight north neither lat nor
> > lon stay constant.
> >
> > How would I go about orthorectifying my scenario.  Would tilecache
> > take care of this?  Would some minor adjustments to the panning work?
> >
> > Thanks,
> > Linda Rawson
> > _______________________________________________
> > Users mailing list
> > Users at openlayers.org
> > http://openlayers.org/mailman/listinfo/users
>
>
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