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Thu Oct 30 11:35:11 2014

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QGIS Planet

QGIS now with 100% more MS SQL Server 2008 support

Ok the title is a bit of a lie. QGIS did support MS SQL Server 2008 before by using OGR but this is a native provider so it’s a lot more integrated..

Good news everyone!

QGIS now has a native MS SQL 2008 provider. The provider can found using the new toolbar button (purple icon) or in the MS SQL node in the QBrowser tree. The provider also supports drag and drop import.

The work was sponsored by Digital Mapping Solutions (Australia) and completed by Tamas Szekeres

Any bugs can be assigned to “tamas” on hub.qgis.org.

A big thanks to both Digital Mapping Solutions and Tamas.

This addition will open QGIS up to a whole new set of users who have to use MS SQL but love QGIS.

Currently this is only in master but I will be in the 1.8 release when it comes out.

Note: At the moment you have to have a geometry_columns table in the database in order to connect, this table is the same format used by PostGIS and can be made by importing a layer using the ogr2ogr method. There will be a fix coming for this at some stage.


Filed under: Open Source, qgis Tagged: MS SQL Server 2008, MS SQL Spatial, Open Source, osgeo, qgis, Quantum GIS

QGIS support for MS SQL Server 2008 – Coming Soon!

Good news!

Support for MS SQL Server 2008 in QGIS is coming soon.   A native QGIS provider for MS SQL Server is currently being worked on to make using, managing, and editing SQL Server data in QGIS just as easy as PostGIS.

The work is being sponsored by the Australian company Digital Mapping Solutions. So a very big thanks to them for this great feature!

There is no ETA on when it will be added to the main QGIS build, but the provider is currently in testing stage and hopefully will be in there soon.

So if you have been itching to try SQL Server data in QGIS, hang in there as a good solution is just around the corner.

P.S The other blog posts on this topic I used ogr, this method will still work fine after the native provider is added, however the native driver will add a nicer interface including integration into the QBrowser, better optimization for the QGIS code, and hopefully same feel as the PostGIS experience.


Filed under: Open Source, qgis Tagged: digital mapping solutions, FOSSGIS, gis, ms sql server, MS SQL Server 2008, MS SQL Spatial, ogr, Open Source, qgis, Quantum GIS

Opening MS SQL Server 2008 Spatial tables in QGIS – Correctly

Turns out the last blog post I did on this subject contained a few errors, mainly that QGIS wouldn’t render the layer when you opened it.

The answer is so obvious it’s almost embarrassing :)

In order to open and display a SQL Server 2008 layer in QGIS correctly, via OGR, you must have a geometry_columns table in your database with the name, geometry type and srid of the layer. That’s it! Oh look, it was even right in front of me in the OGR code for the mssqlspatial driver.

int OGRMSSQLSpatialTableLayer::FetchSRSId()
{
    CPLODBCStatement oStatement = CPLODBCStatement( poDS->GetSession() );
    oStatement.Appendf( "select srid from geometry_columns "
                    "where f_table_schema = '%s' and f_table_name = '%s'",
                    pszSchemaName, pszTableName );

    if( oStatement.ExecuteSQL() && oStatement.Fetch() )
    {
        if ( oStatement.GetColData( 0 ) )
            nSRSId = atoi( oStatement.GetColData( 0 ) );
    }

    return nSRSId;
}

So the process to open a MS SQL 2008 spatial layer in OGR is as follows.

There are two main tables which tell OGR how to read a layers projection:

  • geometry_columns
  • spatial_ref_sys

geometry_columns contains the table name and the key for the table spatial_ref_sys which contains the projection string. The projection string is the info that QGIS needs in order to correctly render a layer.

The easiest way to get the correct tables is to let OGR handle it for you via ogr2ogr, then just adding any other tables you may have already in your database to the geometry_columns table.

So to get ogr2ogr to create the right tables for you it’s as simple as running the following command from inside the OSGeo4W shell, changing the connection string part of course:

ogr2ogr -overwrite -f MSSQLSpatial "MSSQL:server=.\MSSQLSERVER2008;database=geodb;trusted_connection=yes" "rivers.tab"

(sample taken from http://www.gdal.org/ogr/drv_mssqlspatial.html)

Uploading even just one table this way will create both tables and fill in the needed info.
The geometry_columns table:

f_table_catalog f_table_schema f_table_name f_geometry_column
geodb dbo rivers ogr_geometry
coord_dimension srid geometry_type
2 32768 POLYGON

The spatial_ref_sys table:

srid auth_name auth_srid srtext proj4text
32768 NULL NULL PROJCS[“UTM_Zone_56_Southern_Hemisph…. +proj=utm +zone=56 +south +ellps=GRS80 +units=m +no_defs

So if you have already existing tables in your MS SQL 2008 database that were loaded, via say MapInfo’s EasyLoader, you would just upload one table via ogr2ogr to create the two tables needed by QGIS(using OGR) and then add the other tables to the geometry_columns table. If they are all in the same projection than you are in luck as you will only need to upload one in order to get the right strings in the spatial_ref_sys table, if not just upload a small sample for each projection.

Then you can open the table in QGIS using:

uri = "MSSQL:server={serverName};database={databaseName};tables={tableName};trusted_connection=yes"
qgis.utils.iface.addVectorLayer(uri,'{yourLayerNameHere}','ogr')

Tip: In order to test you have correctly set the table in geometry_columns you can run another ogr tool ogrinfo:

ogrinfo -al "MSSQL:server=localhost;database={your database};tables={your table}" -fid 1

If you see a value in Layer SRS WKT: then chances are it’s set right and QGIS should be able to render it, however if you see: Layer SRS WKT:(unknown) Than chances are QGIS will not render it correctly.

Hopefully this help people use MS SQL 2008 Spatial with QGIS, a important step I think in the world of using QGIS on Windows (especially when you don’t have the freedom to run PostGIS:) ).

I might even do a video tutorial when I get some free time after my exams and my wedding.


Filed under: Open Source, qgis Tagged: gis, map-rendering, mapping, MS SQL Server 2008, MS SQL Spatial, ogr, Open Source, OSS, qgis, Quantum GIS

Opening MS SQL Server 2008 Spatial tables in QGIS

EDIT:  If you are having trouble opening MS SQL 2008 in QGIS I will have a blog post coming explaining how to correct it. Or you can read the comments between TheGeoist and I below which will have the answer.

Just a quick tip.

Thanks to GDAL/OGR 1.8 QGIS can now open MS SQL Server 2008 spatial tables via the OGR MSSQLSpatial driver.

First you must be running a version of QGIS that is using GDAL/OGR 1.8.  Opening the QGIS about page will tell you if it is supported.

Need version 1.8 or higher

As I am writing this on my Ubuntu install I only have version 1.6.3 but the latest dev version of QGIS (upcoming 1.7 release) for Windows in the OSGeo4W installer is complied with version 1.8.

Now open the python console in QGIS and type the following:

uri = "MSSQL:server={serverName};database={databaseName};tables={tableName};trusted_connection=yes"
qgis.utils.iface.addVectorLayer(uri,'{yourLayerNameHere}','ogr')

Replacing {serverName} with your server name, if installed on your local machine you can use localhost; {databaseName} with the name of the database with the tables;{tableName} with the table to open; {yourLayerNameHere} with the name you would like the layer to have in the map legend.

After that you should see your MS SQL Spatial table displayed in QGIS, with editing support.

At the moment there is no nice interface in QGIS to open MS SQL tables like there is for PostGIS, although that might be a good plugin project for someone to work on.


Filed under: Open Source, qgis Tagged: gis, mapping, MS SQL Server 2008, MS SQL Spatial, Open Source, OSS, python, qgis, Quantum GIS

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