[gdal-dev] Question about .aux.xml sidecar file handling...

[Even Rouault]

On jeudi 19 janvier 2017 06:15:15 CET Carl Godkin wrote:
> On Thu, Jan 19, 2017 at 3:17 AM, Even Rouault <even.rouault at spatialys.com>
> 
> wrote:
> > On mercredi 18 janvier 2017 06:55:49 CET Carl Godkin wrote:
> > > Hi,
> > > 
> > > 
> > > 
> > > I have a geological map in a pair of files called USGS.tif and
> > > 
> > > USGS.tif.aux.xml
> > > 
> > > 
> > > 
> > > The XML seems to have ground control points (<SourceGCPs>) and a
> > 
> > geographic
> > 
> > > coordinate system (<SpatialReference>)
> > 
> > GDAL .aux.xml files do no have <SourceGCPs> or <SpatialReference>
> > elements, so it looks like this .aux.xml file is a USGS specific one
> > (yikes!)
> > 
> > The names understood by GDAL are <GCPList> and the SRS is stored as a
> > Projection attribute of <GCPList>
> 
> Hi Even & Jukka,
> 
> This folder on my Google drive contains the two folders.  They are not
> private or anything so please feel free to test with them if you need them:
> 
> https://drive.google.com/drive/folders/0B-pQ1UXElObET3Nfbk9qQ1VDZWc

It seems that in ArcGIS 9.3, .aux.xml had their <GeodataXform> right at the root of the XML 
tree (so not at all compatible with GDAL .aux.xml formalism), and that in ArcGIS 10, they 
moved it as a GDAL PAM xml:ESRI metadata domain.

I've just added in trunk support for reading those GCPs. The "fun" fact is that the (pixel,line) 
coordinates of GCPs are given not in pixels from the top-left corner of the image but in 
inches from the bottom-left corner...

Even

-- 
Spatialys - Geospatial professional services
http://www.spatialys.com
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