[postgis-users] [Qgis-developer] Fwd: WKTRaster Plugin 0.1

Tue Nov 30 09:13:33 PST 2010

2010/11/30 Maurício de Paulo <mauricio.dev at gmail.com>:
> Great. I've included a new combobox on the ui. I'm going to implement it and
> release as version 0.3.
> Any other sugestions on what a "Load postgis raster" plugin should do?
> Best regards,
> Mauricio de Paulo
>

I suppose you can specify the database/schema/table names. Apart from
that, the 3 working modes are the basics. May I test the plugin?

> 2010/11/30 Jorge Arévalo <jorge.arevalo at deimos-space.com>
>>
>> 2010/11/30 Maurício de Paulo <mauricio.dev at gmail.com>:
>> > Yes, the main issue we found was the performance of display. So
>> > something
>> > inside the driver is slowing the reading process done by qgis.
>> > I took a look at the MODE option. It can be set in the user interface on
>> > my
>> > plugin. I think that a combobox storing "Read whole table" "Read one
>> > row"
>> > and "Read entire database" should pass the right options. Is it the real
>> > interpretation of this parameter? Any sugestions?
>> > Best regards,
>> > Mauricio de Paulo
>> >
>>
>> Yes, Basically, one spatial query is executed for each data petition.
>> That can (must) be improved. I know it.
>>
>> About the parameter, yes. There is, basically, 3 ways of using the driver:
>>
>> - Providing only a database name, and optionally, a schema name: The
>> driver returns all the existent raster tables as subdatasets
>> - Providing a database name, a table name and optionally, a column
>> name: The driver returns all the rows of the raster table as a
>> subdataset. This is, consider each row as a different raster. The same
>> if you provide "mode=1" as parameter.
>> - Providing a database name, a table name and "mode = 2": The driver
>> consider that all the rows of the table are tiles of a bigger raster
>> coverage, and constructs one raster object based in the whole extent
>> of all the raster tiles. For now, just working with regularly blocked
>> rasters.
>>
>> So, about your combobox, the option "read the entire database" (or
>> "read one schema") should disable the selection of a table name (it is
>> the first of the 3 points).
>>
>> Best regards,
>>
>> --
>> Jorge Arévalo
>> Internet & Mobilty Division, DEIMOS
>> jorge.arevalo at deimos-space.com
>> http://mobility.grupodeimos.com/
>> http://gis4free.wordpress.com
>>
>>
>> P.S.: My mails to QGIS list are rejected, but I think that could be
>> interesting. I'll subscribe to the list.
>>
>> >
>> > 2010/11/30 Jorge Arévalo <jorge.arevalo at deimos-space.com>
>> >>
>> >> 2010/11/30 Maurício de Paulo <mauricio.dev at gmail.com>:
>> >> > I've been using GDAL 1.7 and postgis 1.5.1
>> >> > Both postgis' windows and ubuntu versions are able to load the
>> >> > rasters
>> >> > fine.
>> >> > We've encountered some trouble with what we believe is the "regular
>> >> > blocking" issue.
>> >> > wktraster's QGIS plugin and MapServer source were tested on ubuntu
>> >> > 10.04
>> >> > with ubuntugis binaries.
>> >> > Perfomance looks like a huge issue at the moment. I didn't
>> >> > investigate
>> >> > why.
>> >> > I can probably take look back at this issue when I get back home to
>> >> > my
>> >> > ubuntu box. I can't test on windows because there is no QGIS compiled
>> >> > with
>> >> > gdal 1.7 for windows prebuilt.
>> >> > This new gdal driver version was included in which gdal release?
>> >> > Maybe
>> >> > we
>> >> > can recompile everything and test again.
>> >> > Best regards,
>> >> > Mauricio
>> >> >
>> >>
>> >> Yes, the old version of the driver had some known (by me) problems:
>> >>
>> >> - Depends on the information stored in "raster_columns" table, in
>> >> PostGIS installation, and it shouldn't.
>> >> - Performance. I need to review this. It's a question of PostGIS
>> >> queries.
>> >>
>> >> In October, I commited a new version with some improvements. It's in
>> >> GDAL trunk since release 20912
>> >> (http://trac.osgeo.org/gdal/changeset/20912). Anyway, I'd like to
>> >> improve more things in this driver. The reading process is the big
>> >> issue right now. The best way to read blocks of data.
>> >>
>> >> If you use it, the most important thing is now you need to specify an
>> >> extra parameter: "mode". Further information here:
>> >> http://trac.osgeo.org/gdal/wiki/frmts_wtkraster.html
>> >>
>> >> Best regards,
>> >> --
>> >> Jorge Arévalo
>> >> Internet & Mobilty Division, DEIMOS
>> >> jorge.arevalo at deimos-space.com
>> >> http://mobility.grupodeimos.com/
>> >> http://gis4free.wordpress.com
>> >>
>> >> > 2010/11/29 Jorge Arévalo <jorge.arevalo at deimos-space.com>
>> >> >>
>> >> >> Good news! Which version of GDAL/PostGIS are you using? I commited a
>> >> >> new version of the GDAL driver on October, and included WKT Raster
>> >> >> as
>> >> >> official part of PostGIS on September 26th.
>> >> >>
>> >> >> On Mon, Nov 29, 2010 at 9:40 PM, Maurício de Paulo
>> >> >> <mauricio.dev at gmail.com> wrote:
>> >> >> > Ok, after a few minutes of implementation here it is. Now the
>> >> >> > plugin
>> >> >> > lists
>> >> >> > the tables from the database and shows some of it's metadata. Now
>> >> >> > I
>> >> >> > think
>> >> >> > it's fully functional. If anyone finds a bug , please tell me.
>> >> >> > Best regards,
>> >> >> >
>> >> >> > On Mon, Nov 29, 2010 at 3:50 PM, Maurício de Paulo
>> >> >> > <mauricio.dev at gmail.com>
>> >> >> > wrote:
>> >> >> >>
>> >> >> >> Hi Jorge,
>> >> >> >> Good news. The plugin wktraster is exactly a tool to connect qgis
>> >> >> >> to
>> >> >> >> postgis rasters through GDAL and visualize the data.
>> >> >> >> Stefan asked about the processing. This is something the plugin
>> >> >> >> doesn't
>> >> >> >> do.
>> >> >> >> I've tested with a friend both qgis (with the plugin) and
>> >> >> >> mapserver
>> >> >> >> loading postgis rasters. Both worked fine, and the only
>> >> >> >> requirement
>> >> >> >> is
>> >> >> >> qgis
>> >> >> >> compiled against gdal 1.7.
>> >> >> >> I'm interested in updating the plugin this week to work as I've
>> >> >> >> planned.
>> >> >> >> It's going to speak for itself.
>> >> >> >> Best Regards,
>> >> >> >> Mauricio
>> >> >> >> Ps.: Anyone willing to help and join this effort is always
>> >> >> >> welcome.
>> >> >> >>
>> >> >> >> On Mon, Nov 29, 2010 at 3:45 PM, Jorge Arévalo
>> >> >> >> <jorge.arevalo at deimos-space.com> wrote:
>> >> >> >>>
>> >> >> >>> Hi,
>> >> >> >>>
>> >> >> >>> If you want a GDAL version compiled with PostGIS Raster support
>> >> >> >>> on
>> >> >> >>> Windows, you may take a look here:
>> >> >> >>> http://vbkto.dyndns.org:1280/sdk/
>> >> >> >>>
>> >> >> >>> Visualizing PostGIS Raster data via GDAL driver is one of my
>> >> >> >>> TODO
>> >> >> >>> tasks. I don't have too much free time now, but if you're
>> >> >> >>> interested
>> >> >> >>> on this topic, and you're going to test it, please let me know.
>> >> >> >>> There
>> >> >> >>> are more people interested on that, and I'm providing support to
>> >> >> >>> some
>> >> >> >>> of them (not as much support as I'd like, because the time...)
>> >> >> >>>
>> >> >> >>> Best regards,
>> >> >> >>>
>> >> >> >>> --
>> >> >> >>> Jorge Arévalo
>> >> >> >>> Internet & Mobilty Division, DEIMOS
>> >> >> >>> jorge.arevalo at deimos-space.com
>> >> >> >>> http://mobility.grupodeimos.com/
>> >> >> >>> http://gis4free.wordpress.com
>> >> >> >>>
>> >> >> >>> 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.
>> >> >> >>> > _______________________________________________
>> >> >> >>> > postgis-users mailing list
>> >> >> >>> > postgis-users at postgis.refractions.net
>> >> >> >>> > http://postgis.refractions.net/mailman/listinfo/postgis-users
>> >> >> >>> >
>> >> >> >>
>> >> >> >>
>> >> >> >>
>> >> >> >> --
>> >> >> >> Mauricio de Paulo
>> >> >> >> Engenheiro Cartografo
>> >> >> >>
>> >> >> >
>> >> >> >
>> >> >> >
>> >> >> > --
>> >> >> > Mauricio de Paulo
>> >> >> > Engenheiro Cartografo
>> >> >> >
>> >> >> >
>> >> >>
>> >> >>
>> >> >>
>> >> >> --
>> >> >> Jorge Arévalo
>> >> >> Internet & Mobilty Division, DEIMOS
>> >> >> jorge.arevalo at deimos-space.com
>> >> >> http://mobility.grupodeimos.com/
>> >> >> http://gis4free.wordpress.com
>> >> >
>> >> >
>> >> >
>> >> > --
>> >> > Mauricio de Paulo
>> >> > Engenheiro Cartografo
>> >> >
>> >> >
>> >
>> >
>> >
>> > --
>> > Mauricio de Paulo
>> > Engenheiro Cartografo
>> >
>> >
>
>
>
> --
> Mauricio de Paulo
> Engenheiro Cartografo
>
>

-- 
Jorge Arévalo
Internet & Mobilty Division, DEIMOS
jorge.arevalo at deimos-space.com
http://mobility.grupodeimos.com/
http://gis4free.wordpress.com