[gdal-dev] RFC 61: Call for vote on adoption

[Even Rouault]

Le vendredi 12 février 2016 11:26:46, Ari Jolma a écrit :
> I've fixed this so that currently all tests pass (at least locally).
> 
> Now Shapefiles, which are created XY come back as XY, XYM as XYM, XYZ as
> XYZ, and XYZM as XYZM. Also one should be able to set the required
> coordinate combination using parameters - that's not comprehensively
> tested however.
> 

Great

> There are still a couple of fixme's in the code (shape2ogr.cpp), writing
> a shape should take into account the requested coordinate combination
> and whether to skip Ms or write them as "no data" (value < 1038
> according to the doc).

-10^38

> 
> I changed the code for OGRFeature::SetGeomFieldDirectly to set or unset
> the geometry M or Z coordinates depending on the geometry field type of
> the feature. That's somewhat bold but the way I did it at least did not
> break anything in the tests.

Agreed it is a non trivial change. But it does break things. Crashes in the 
CSW driver for example :
https://travis-ci.org/rouault/gdal_coverage/builds/108752731 .
And other non crashing failures.
Perhaps do this dimension harmonization not in SetGeomFieldDirectly() but in a 
helper function and call it in the shapefile driver if you need it ?
We could also try to fix drivers/tests, but there may be cases where drivers 
cannot declare a consistant coordinate dimensionnality because they have a mix 
of {Geom} and {Geom}Z features

> 
> Ari
> 
> 10.02.2016, 13:26, Ari Jolma kirjoitti:
> > One more issue came up.
> > 
> > Shapefiles, which have Z will also have M, at least a placeholder for it.
> > 
> > Having shapefiles as XYZM always in that case may be problematic.
> > 
> > It is possible to use the open options SHPT=type to override the
> > default. We could have Z => XYZ as default for backwards compatibility
> > and require open option for Z  => XYZM.
> > 
> > Ari
> > 
> > 09.02.2016, 17:07, Ari Jolma kirjoitti:
> >> I declare this motion passed with +1 from Even, Tamas, Jukka and
> >> Daniel and no -1.
> >> 
> >> I'll commit soon the changes to the core and then later the drivers:
> >> memory, shape and pg. The goal is to keep the travis test build passing.
> >> 
> >> Ari
> >> 
> >> 05.02.2016, 10:04, Ari Jolma kirjoitti:
> >>> I'd like to ask the PSC and others to vote on adopting RFC 61:
> >>> Support for measured geometries.
> >>> 
> >>> The draft RFC is at
> >>> 
> >>> https://trac.osgeo.org/gdal/wiki/rfc61_support_for_measured_geometries
> >>> 
> >>> and a draft implementation is at
> >>> 
> >>> https://github.com/ajolma/GDAL-XYZM
> >>> 
> >>> which is tested at
> >>> 
> >>> https://travis-ci.org/ajolma/GDAL-XYZM
> >>> 
> >>> (the test #34, which passed, was the so far last one after core
> >>> changes with unchanged autotests and a rather comprehensive set of
> >>> WKT tests in the Perl tests directory)
> >>> 
> >>> This is seemingly a small change but it is at the heart of OGR so it
> >>> has some important implications. The only backwards
> >>> incompatibilities that have appeared so far are with some drivers,
> >>> for example shapefile, which can be lessened with, e.g., open options.
> >>> 
> >>> Best,
> >>> 
> >>> Ari

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