[Geopackage] New Blog Post

Jeff Yutzler jeffy at imagemattersllc.com
Thu Dec 15 12:43:49 EST 2016


Even,
Thanks for your comments.
* Req 108: Fixed! (BTW we take pull requests...)
* RE EPSG 4979: I'm not sure what to tell you here. We found that HAE was a
better fit for most of our user base. Keep in mind that this is only a
default and that users are free to use any valid CRS. In reality 3D CRSs
are a mine field anyway.
* RE the ancillary table: If I recall, we wanted to keep the schema of the
tile pyramid user data tables consistent between content types. Having an
ancillary table enabled us to do this.
-Jeff



On Thu, Dec 15, 2016 at 12:10 PM, Even Rouault <even.rouault at spatialys.com>
wrote:

> On jeudi 15 décembre 2016 11:42:12 CET Jeff Yutzler via Geopackage wrote:
>
> > I just published a new blog post regarding the new Elevation Extension:
>
> > http://geopackage.blogspot.com/2016/12/elevation-extension-update.html
>
>
>
> Hi,
>
>
>
> Looks good to me on a quick skim.
>
>
>
> A few comments:
>
>
>
> - req 108: typo : geopackage_spatial_ref_sys should reed
> gpkg_spatial_ref_sys
>
>
>
> - the requirement for the 4979 entry in gpkg_spatial_ref_sys is a bit
> surprising. EPSG:4979 is the WGS84 datum with *ellipsoidal* heights. 99.9%
> of the DEM you can find or buy use geoidal / MSL heights. EPSG:6893 = "WGS
> 84 / World Mercator + EGM2008 height" would make more sense to me.
>
>
>
> - the design of the tile pyramid user data table joint with
> gpkg_2d_gridded_tile_ancillary looks a bit convoluted. Why not just putting
> the scale, offset, min, max, mean, std_dev columns in the tile pyramid user
> data table directly ?
>
>
>
> Even
>
>
>
>
>
> >
>
> > Regards,
>
> > Jeff
>
>
>
>
>
> --
>
> Spatialys - Geospatial professional services
>
> http://www.spatialys.com
>



-- 
Jeff Yutzler
Image Matters LLC <http://www.imagemattersllc.com/>
Mobile: (703) 981-8753
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