Hey Jared,
On Sun, Dec 28, 2014 at 1:27 PM, Jared Erickson <[email protected]>
wrote:
> Triggers sound like a good idea. As for the geometry objects, I think the
> spec has changed.
>
>
> https://github.com/opengeospatial/geopackage/blob/master/spec/2a_features.adoc#core-types
>
> The geometry encoding is the same, but the column type should be POINT,
> LINESTRING, POLYGON ect.. instead of blob. The genomes_belgium.gpkg [1]
> example data set and GDAL both encode the geometry columns as POINT et al.
>
So reading through this I am not seeing where it says that geopackage must
use types named "Point", "LineString", etc... just that those types of
objects are supported. Apologies if I am missing something (the links don't
work when rendering with github). But that said I just realized that
apparently you can use any type name you want in sqlite3 and in actuality
all typing is dynamic :)
All that said no objection here about using more specific type names.
>
> Do you think it would be ok to set the default extent in gpkg_contents to
> be 0,0,1,1 or the extent of the projection? GDAL can’t open geopackage
> databases without some value for min_x, min_y, max_x, max_y. ogrinfo
> 1.11.0 errors out with a segmentation fault and QGIS 2.6 crashes.
>
> Do you mean for datasets with no features in them? It would seem kind of
"wrong" to use a valid extent for datasets with entries... would an empty
bounds (0,0,0,0) or an invalid one (1,1,0,0) work?
> Thanks,
> Jared
>
> [1] http://www.geopackage.org/data/geonames_belgium.gpkg
>
>
>
> On Dec 28, 2014, at 10:10 AM, Justin Deoliveira <[email protected]>
> wrote:
>
> Hey Jared,
>
> Perhaps I haven't looked a the spec recently but I thought with geopackage
> geometry objects were supposed to be represented as blobs so that it could
> be used without the need for any other libraries like spatialite. Unless
> there is some sort of type aliasing going on?
>
> As for updating bounds in gpkg_contents automatically I am thinking that
> the driver should put some triggers in place to do this. We could re-use
> the functions that Niels implemented for spatial indexing capabilities to
> pull out the min/max x/y from geometry blobs for this.
>
> -Justin
>
>
>
> On Fri, Dec 26, 2014 at 4:24 PM, jerickson <[email protected]>
> wrote:
>
>> Hi all!
>>
>> One of my holiday vacation projects is to get a Geotools generated
>> GeoPackage vector database working with QGIS and GDAL. The first issue I
>> ran into was that QGIS and GDAL don't recognize the geometry column
>> because
>> it's type is BLOB. GDAL creates geometry columns with a type like
>> GEOMETRY,
>> POINT, MULTIPOLYGON ect... I have a fix for this. The second issue is
>> that
>> QGIS and GDAL expect the gpkg_contents entry to have valid min_x, min_y,
>> max_x, and max_y values. Is there some way to have GeoTools update this
>> bounds after every write?
>>
>> Thanks,
>> Jared
>>
>>
>>
>>
>> --
>> View this message in context:
>> http://osgeo-org.1560.x6.nabble.com/GeoPackage-and-QGIS-GDAL-Compatibility-tp5179287.html
>> Sent from the geotools-devel mailing list archive at Nabble.com.
>>
>>
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>
>
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