There is no easy automated way of detecting existing files, since the files
are technically valid, the tiles are just in the wrong order. Existing
files will be quite apparent from visual inspection however.
How many existing files are out there depends how many people have been
using the GeoServer GeoPackage WMS output format, as that is the only way
to generate these files.
Torben
On Thu, Apr 27, 2017 at 1:39 PM, Jody Garnett <jody.garn...@gmail.com>
wrote:
> Any good idea on how to detect and fix existing files? How many existing
> files will be out there?
>
> --
> Jody Garnett
>
> On 26 April 2017 at 13:17, Torben Barsballe <tbarsba...@boundlessgeo.com>
> wrote:
>
>> I've discovered some interesting behaviour in the GeoPackage Raster
>> Mosaic implementation over the last few days.
>>
>> I tried viewing a GeoPackage generated from the GeoServer GeoPackage WMS
>> output format in QGIS, and observed that tile order is reversed along the
>> y-axis.
>>
>> QGIS used GDAL for parsing GeoPackages. After running this issue by the
>> GDAL team, I was directed to this line of the OGC GeoPackage spec
>> <http://www.geopackage.org/spec/#tile_matrix>:
>>
>> The tile coordinate (0,0) always refers to the tile in the upper left
>>> corner of the tile matrix at any zoom level, regardless of the actual
>>> availability of that tile
>>
>>
>> Adding some test cases to the GeoTools GeoPackage plugin, I can confirm
>> that GeoTools gets this order wrong. Among other things, this means that
>> GeoTools / GeoServer will incorrectly read valid GeoPackage files. A fix
>> can be found here: https://github.com/geotools/geotools/pull/1567
>>
>> Moving along to GeoServer, it appears there are similar problems with the
>> GeoServer GeoPackage Community module, namely in
>> the GeoPackageGetMapOutputFormat.
>>
>> I believe I have a fix, but am currently being slowed down by the fact
>> that the GeoPackage module tests don't seem to be passing on master.
>>
>>
>> *This issue does bring up a problem*: Because GeoTools / GeoServer is
>> consistently wrong (a GeoPackage generated by GeoServer will be read in as
>> "correct"), this bug fix could cause problems for anyone who has solely
>> been using GeoPackage Rasters that were generated by GeoTools / GeoServer.
>>
>> For more details:
>> https://osgeo-org.atlassian.net/browse/GEOT-5715
>> https://osgeo-org.atlassian.net/browse/GEOS-8112
>> https://trac.osgeo.org/gdal/ticket/6871
>>
>> Torben
>>
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>>
>>
>
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