[josm-dev] Problems creating TileSource for ArcGIS REST API

[Ian Dees]

I don't have any more time to look at this right now, but this is the URL I
use in my tile cache for this layer (I used it to map some of Virginia
myself a while back):

http://gismaps.virginia.gov/arcgis2/rest/services/VBMP2006_2007/MapServer/export?f=image&format=jpg&bbox=$xmin,$ymin,$xmax,$ymax&imageSR=102113&bboxSR=102113&size=$width,$height&layers=show:0

On Thu, Feb 17, 2011 at 2:39 PM, Josh Doe <josh at joshdoe.com> wrote:

> Ian,
> Thanks for the fast response. I believe I tried that, but to make sure
> I tried it again, and it doesn't work. For some reason with
> imageSR=102113 I get a blank (white) image. For fun I also tried the
> equivalent imageSR=102100 with no luck. You can see the request is
> blank here [1], while clearing imageSR results in an image, though not
> of the right projection. To be honest I don't really understand how
> the imageSR relates to the bbox and bboxSR.
>
> Is it possible this instance of the ArcGIS server can't reproject the
> image to this SR? I'm outside of my knowledge area if you haven't
> guessed already. :)
>
> Thanks,
> Josh
>
> [1]:
> http://gismaps.virginia.gov/arcgis2/rest/services/VBMP2006_2007/MapServer/export?bbox=-77.310791,38.794768,-77.308044,38.792627&size=256,256&bboxSR=4326&imageSR=102113&format=jpg&f=html
> [2]:
> http://gismaps.virginia.gov/arcgis2/rest/services/VBMP2006_2007/MapServer/export?bbox=-77.310791%2C38.794768%2C-77.308044%2C38.792627&bboxSR=4326&layers=&layerdefs=&size=256%2C256&imageSR=&format=jpg&transparent=false&dpi=&f=html
>
> On Thu, Feb 17, 2011 at 3:16 PM, Ian Dees <ian.dees at gmail.com> wrote:
> > Use bboxSR=4326 (to specify the bounding box in 4326) and imageSR=102113
> to
> > get the image back projected to Spherical Mercator.
> > The imageSR parameter may be called something else, but I do know that an
> > output projection option exists somewhere.
> >
> > On Thu, Feb 17, 2011 at 2:09 PM, Josh Doe <josh at joshdoe.com> wrote:
> >>
> >> Ian,
> >> I've tried various combinations of spatial references and haven't
> >> quite got it working. I use the tileYToLat/tileXToLon functions which
> >> give me decimal degrees in WGS84 (EPSG:4326), so I can't use
> >> bboxSR=102113 without converting those coordinates. With the Proj4J
> >> plugin I used EPSG:3857 (equivalent to ESRI:102113 and ESRI:102100),
> >> and that eliminates the gaps but now there are slight shifts between
> >> each tile, so clearly something is still awry. I thought setting
> >> imageSR=102113 would fix the slight shifts, but then I don't get any
> >> image returned.
> >>
> >> Tobias,
> >> I've found it very confusing to understand what spherical mercator is
> >> and the various codes involved, so much so that I created a wiki page
> >> on EPSG:3857 [1].
> >>
> >> All,
> >> One thing that bothers me in JOSM is the Mercator projection claims to
> >> be EPSG:3857, however it gives values in radians, not meters which
> >> EPSG:3857 uses. I'm not even sure what EPSG/ESRI/etc identifier
> >> corresponds to to this, but I think we should change it to avoid
> >> confusion (took me a while to realize it was "wrong").
> >>
> >> Shouldn't we change this code to avoid confusion and to "be right"?
> >> I'm guessing people use the projection, so we shouldn't "fix" it but
> >> rather give it the correct code if we can find it or invent one,
> >> probably via SpatialReference.org.
> >>
> >> Thanks,
> >> -Josh
> >>
> >> [1]: http://wiki.openstreetmap.org/wiki/EPSG:3857
> >>
> >> On Thu, Feb 17, 2011 at 12:35 PM, Tobias Wendorff
> >> <tobias.wendorff at tu-dortmund.de> wrote:
> >> > Am 17.02.2011 17:15, schrieb Ian Dees:
> >> >>
> >> >> Don't reproject your coordinates to Virginia, just tell ArcGIS that
> >> >> your
> >> >> request bounding box is in Spherical Mercator projection by passing
> in
> >> >> a
> >> >> projection id of 102113.
> >> >
> >> > Interesting information on this topic:
> >> > http://forums.esri.com/Thread.asp?c=93&f=984&t=288073&g=1
> >> >
> >
> >
>