[GRASS-user] Strategies to Import Geological Cross Sections

[Markus Neteler]

Hi,

On Tue, Jan 12, 2016 at 11:37 PM, Phillip Allen
<phillipjallen830 at gmail.com> wrote:
> Hi all,
>
> I have digitized a few geological cross-sections each consisting of a 1
> polygon & 1 polyline layer (representing lithology & faults respectively).
> The layers were digitized in plan view with arbitrary coordinates in meters
> and imported into PostgreSQL/PostGIS. I then created views using
> ST_Translate(ST_RotateZ(ST_RotateX(ST_Translate(geom, ))) to correctly plot
> the cross-section polygons & polylines in 3D space. One day I need to learn
> how to multiply matrices so I can do it all in a single step!
>
> I just tried to import them into GRASS 7.0.3RC1 using v.in.ogr and got the
> following error message:
>
> ERROR 1: Reading EWKB with 4-dimensional coordinates (XYZM) is not supported
>
> Can GRASS not import PostGIS 3D data?

This error (given the fact that it is "ERROR 1" must come from OGR and
not from GRASS GIS as we don't use numbers).
Hence, ogr2ogr would likely report the same.

> Is it the vertical Polygon with zero area topology problem?
>
> What other options do I have to get 3D-cross-section data into GRASS?
>
> I tried to use the ST_Extrude (to avoid topology problems) command in
> PostGIS and Grass's v.in.ogr didn't like that either. Is there another way
> to get 3D objects into GRASS?

Which OGR version is installed? As soon as it works there I am
confident that it also works with v.in.ogr.

I see some discussion about the problem also here (random search result):

https://lists.osgeo.org/pipermail/gdal-dev/2015-February/041056.html

> I want to use v.hull on the vertical cross-sectional data and symbolize some
> geochemical drill data in Grass's 3D viewer.

IMHO it needs to be solved in OGR first (maybe it is in the latest
version, I didn't verify).

Best,
Markus