[Qgis-user] Re: [Qgis-developer] Fwd: WKTRaster Plugin 0.1

[Maurício de Paulo]

Hi Stefan!
Well, some wktraster operations returns rasters and some returns vectors.
I think that the ones that returns vectors (st_intersection) can be viewed
as regular postgis tables if selected in a rt_sql plugin.
I've never tested it, though. The idea is that if they return vector then
qgis should read it as postgis geometries.
I'm on a windows notebook now so it's going to take some time to set a
raster/vector wktraster overlay to test it.
I'm afraid it might not work because of the data structure of the height on
st_intersection not being a coordinate and instead being an array. That's
all I remember from the tests I did back then and it could stop the result
from being displayed without proper treatment.


2010/11/29 Stefan Keller <sfkeller at gmail.com>

> Ok (I'm cross posting to qgis-developer and postgis-users).
>
> I'm still not sure if I did express myself clearly:
> You say, that under Windows, there's no QGIS compiled against GDAL
> 1.7/1.8 with PostGIS Raster support?
>
> What I finally dream of, is using QGIS to display the results of a SQL
> query (either as raster or vector) against at least one raster layer.
> This query contains raster constructors (like ST_Intersection) and
> operations (like ST_Reclass; see
> http://trac.osgeo.org/postgis/wiki/WKTRaster).
>
> Any suggestions?
> -S.
>
>
> 2010/11/29 Maurício de Paulo <... at gmail.com>:
> > Hi Stefan,
> >
> > WKTRaster Plugin just repasses the right information to the GDAL driver.
> > It's not a new qgis driver.
> > I'm planning on implementing the table listing using pyqt this week. I
> was a
> > little delayed by my master's application.
> >
> > The idea in the plugin is simply find the QGIS's conections available,
> list
> > the raster tables inside postgis and pass the right arguments to the gdal
> > driver.
> >
> > At the moment I haven't found any gdal 1.7 windows build with QGIS. GDAL
> 1.7
> > introduces wktraster. The driver conects to postgis raster and read it as
> a
> > binary. It's still VERY unstable and gdal version 1.8 seems to be greatly
> > improved.
> > So what a windows user need to get the plugin to work is a (still not
> found)
> > qgis compiled against gdal 1.7.
> > You can compile your's from source if needed.
> >
> > So, as far as qgis to wktraster, with the plugin qgis reads the wktraster
> as
> > a regular raster. Just for show. If you did some kind of processing and
> > populated a new raster table, qgis is going to read that result too. The
> > plugin is not intended (at the moment at least) to raster processing
> inside
> > postgis. It just loads the table to the screen.
> >
> > In the future, with a more stable wktraster probably someone (or me) is
> > going to write a set of wktraster's tools as a plugin, but for the moment
> it
> > should be run as sql. I advise postgis manager's to the task.
> >
> > Best regards,
> >
> >
> > 2010/11/29 Stefan Keller <... at gmail.com>
> >>
> >> Hi,
> >>
> >> There are new versions around of "PostGIS Raster"
> >> (renamed from formerly known "PostGIS WKT Raster").
> >>
> >> What's the status of your "WKTRaster Plugin 0.1"?
> >> I assume it's rendering the raster values (e.g. from ST_AsBinary) -
> >> not the polygons/geomvals (from ST_DumpAsPolygons), right?
> >> Is there a chance to get it running on Windows too?
> >> Are there other plugins?
> >>
> >> Yours, S.
>



-- 
Mauricio de Paulo
Engenheiro Cartografo
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