[TinyOWS-users] Problem inserting features

Tue Sep 20 16:34:43 EST 2011

Carlos,

Thanks for your explanation and suggestion. I ended up starting fresh 
with the saunders_lines table using my preferred projection for my area 
(FL Albers HARN, i.e. EPSG:3087) by creating a shapefile with some dummy 
features in QGIS, imported that to Postgres using the Spit tool in QGIS 
(setting the projection to 3087), and now QGIS 1.7 edits the data fine 
via WFS. Now back to OpenLayers...

Thanks,
Brian

On 9/20/2011 10:53 AM, Carlos Ruiz wrote:
> Brian,
>
> When you use the shp2pgsql utility, it adds to the table some 
> constraints to ensure that all the geometry insertion/update will be 
> of the same SRID, type and dimension.
>
> So, the definition
>
> ALTER TABLE saunders_lines ADD CONSTRAINT enforce_srid_wkb_geometry 
> CHECK (srid(the_geom) = 900913);
>
> ensures that the SRID of the geometry to insert/update will always be 
> 900913.
>
> You can change the SRID of the geometry if you want to using 
> ST_TRANSFORM, but you first must drop the enforce_srid_wkb_geometry 
> constraint and replace the new value in the postgis spatial_columns 
> table for the saunders_lines row.
>
> The 900913 projection treats the earth as a sphere (this is wrong) and 
> handles the coordinates as X/Y instead as Lat/Lon. You can transform 
> your geometry to SRID 4326 which treats the earth as a geoid, then the 
> coordinates are Lat/Lon and there's no problem with its definition.
>
> Why don't you try this ?
>
> IC Carlos Ruiz
>
> ------------------------------------------------------------------------
> *From:* Brian May <bmay at mapwise.com>
> *To:* Carlos Ruiz <boolean10001 at yahoo.com>; TinyOWS users discuss list 
> <tinyows-users at lists.maptools.org>
> *Sent:* Monday, September 19, 2011 9:33 PM
> *Subject:* Re: [TinyOWS-users] Problem inserting features
>
> More on 900913 issues:
>
> Just for kicks I decided to install QGIS 1.7 - it will make my life 
> better, right? I go and open up my project that I had been testing 
> WFS-T with, test adding a line and saving it - new problem - ERROR: 
> new row for relation "saunders_lines" violates check constraint 
> "enforce_srid_wkb_geometry"
>
> I didn't change anything.
>
> So, after checking out projection defs in different places I find this:
>
> QGIS 1.7 definition of 900913
> +proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 
> +y_0=0 +k=1.0 +units=m +nadgrids=@null +wktext +over +no_defs
>
> QGIS 1.7 definition of 3785
> +proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 
> +y_0=0 +k=1.0 +units=m +nadgrids=@null +no_defs
>
> QGIS 1.7 3875 (new Google Mercator Standard)
> Not there!
>
> From WFS layer metadata (coming out of postgres)
> +proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 
> +y_0=0 +k=1.0 +units=m +nadgrids=@null +wktext +over +no_defs
>
> From postgres spatial_ref_sys table
> +proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 
> +y_0=0 +units=m +k=1.0 +nadgrids=@null +no_defs
>
> End of a thread on the QGIS list discussing these EPSG codes.
> http://www.osgeo.org/pipermail/qgis-developer/2010-February/009183.html
>
> The constraint on my table for srid:
> ALTER TABLE saunders_lines
>   ADD CONSTRAINT enforce_srid_wkb_geometry CHECK (srid(the_geom) = 
> 900913);
>
> So maybe I'm not making things easy on myself having the data in 
> 900913 (or one of its variants)?
>
> Brian
>
> On 9/19/2011 5:05 PM, Carlos Ruiz wrote:
>> Brian,
>>
>> Just about the 900913 projection, maybe it is not found in the 
>> spatial_ref_sys table, also in Mapserver could be not found in proj4, 
>> so I suggest to try with the EPSG:3857 which is the same for 
>> spherical mercator.
>>
>> Cheers from México
>> IC Carlos Ruiz
>>
>> ------------------------------------------------------------------------
>> *From:* Brian May <bmay at mapwise.com> <mailto:bmay at mapwise.com>
>> *To:* TinyOWS users discuss list <tinyows-users at lists.maptools.org> 
>> <mailto:tinyows-users at lists.maptools.org>
>> *Sent:* Monday, September 19, 2011 3:22 PM
>> *Subject:* [TinyOWS-users] Problem inserting features
>>
>> Getting TinyOWS to work has been a long and winding road - still no 
>> success - and almost ready to give up. Here's the latest on what I 
>> have tried and the results.
>>
>> I ended up trying it out on linux and got further down the road, but 
>> different problems. I compiled it from source from SVN. I can insert 
>> features via QGIS and OpenLayers now, but the inserted features do 
>> not have any geometry (confirmed via checking out the table in 
>> postgres). And I can see existing features in QGIS that I manually 
>> added via a direct connect to postgres, but not in OpenLayers! I have 
>> been running down a lot of rabbit holes trying to get this figured 
>> out, burning a lot of time and I could really use some help.
>>
>> Also, I may have found a few bugs in the process. For example, if you 
>> have two geometry columns in your table, and do not inform tinyows of 
>> the additional geometry column via the config file, it produces a 500 
>> error when testing from the browser. Does tinyows expect the_geom vs. 
>> wkb_geometry? Tried both and it seems to operate the same, except 
>> when you have them both there at the same time.
>>
>> I don't remember if this is in the docs, but you must have a record 
>> in the geometry_columns table for tinyows to recognize the layer at 
>> all - you can have your config all set up right, and it just won't 
>> show the layer as being available.
>>
>> If you change the geometry column name in your table and the geometry 
>> column name in the geometry_columns table don't match - doing 
>> ./tinyows --check produces the following error:
>> row number 0 is out of range 0..-1
>> tinyows: src/struct/buffer.c:254: buffer_add_str: Assertion `str' failed.
>> Aborted
>>
>> Is there any reason why having your data in 900913 projection would 
>> be a problem? Wasn't my first choice, but I figured i could eliminate 
>> projection problems that way since the map is in 900913.
>>
>> Also, not sure why, but after some change I made, the url 
>> http://myurl/cgi-bin/tinyows?service=WFS&request=DescribeFeatureType&version=1.1.0& 
>> <http://192.168.2.105:9091/cgi-bin/tinyows?service=WFS&request=DescribeFeatureType&version=1.1.0&> 
>> is producing a much more terse output than before. Haven't figured 
>> out what it is yet, although if I take out my custom layer, and just 
>> have the france demo, the verbose output comes back.
>>
>> If its easier to help debug this, I can open it up to the outside 
>> world temporarily.
>>
>> Any help would be greatly appreciated.
>>
>> Thanks,
>> Brian
>>
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