[postgis-users] OGR2OGR conversion from PostGIS to MapInfo issue

[Obe, Regina]

Thanks Mateusz,

I tried using a view and that seemed to work and the fields now have the
right length and I can resave the file in mapinfo.  The only trick was
that I had to manually insert an entry for my view into the
geometry_columns table for it to work.

My final command shell call looks like this

ogr2ogr -f "MapInfo File" -a_srs "EPSG:2249" update PG:"host=zdnd1
dbname=dnddts" "UPDATE" vwupdate -nln "UPDATE"

thanks again,
Regina



-----Original Message-----
From: Obe, Regina 
Sent: Monday, October 15, 2007 9:44 AM
To: gdal
Subject: RE: [postgis-users] OGR2OGR conversion from PostGIS to MapInfo
issue

 Thanks Mateusz,

I'll give it a try to output the table instead.  Do you think a view
would work instead of a table?  My problem is I don't want to output all
the fields in my table since I have excess stuff they don't need.

Now looking back at my shape export - I had thought it output the field
lengths correctly, but it actually defaulted all of them to 80 so that
explains it.

Regina

-----Original Message-----
From: postgis-users-bounces at postgis.refractions.net
[mailto:postgis-users-bounces at postgis.refractions.net] On Behalf Of
Mateusz Loskot
Sent: Monday, October 15, 2007 9:35 AM
To: PostGIS Users Discussion
Cc: gdal; gdal-announce at lists.osgeo.org
Subject: Re: [postgis-users] OGR2OGR conversion from PostGIS to MapInfo
issue

Obe, Regina wrote:
> I apologize for this cross-posting, but wasn't quite sure which list
> would be best.

Regina,

I believe the best list is the official mailing list of GDAL project:
gdal-dev at lists.maptools.org

> I converted a query from PostGIS to MapInfo for one of our GIS
> specialists here, and apparently all the fields came out as
varchar(254)
> and when they try to resave the file in MapInfo - it doesn't allow
them
> to (I forget the error).  Aside from that, reading the file seems fine
> and you can see the features.  If I do the same but to shape format,
> then the fields have the correct field sizes and everything.
>  
> Is there something I am doing wrong here or is this just a limitation
of
> the Ogr Mapinfo driver?

varchar(256) is a default width of string field in MapInfo format,
if not specified explicitly (http://www.gdal.org/ogr/drv_mitab.html)

I made a short test and it shows that columns are differently
recognized for layer based on SQL query than layer based on a table:

1. Reading point table as a layer determines wiedth of columns:

mloskot at dog:~/dev/gdal/_svn/trunk/gdal$ ogr/ogrinfo -ro PG:dbname=test
point -so
INFO: Open of `PG:dbname=test'
      using driver `PostgreSQL' successful.

Layer name: point
Geometry: Point
Feature Count: 53
Extent: (11.660233, 48.320915) - (21.675484, 53.763435)
Layer SRS WKT:
(unknown)
Geometry Column = the_geom
altitude: String (6.0)
gid: Integer (0.0)
lat: String (12.0)
lon: String (12.0)
longname: String (17.0)
name: String (17.0)
recnum: String (6.0)


2. If layer is based on SQL query, no details about columns width is
given:

mloskot at dog:~/dev/gdal/_svn/trunk/gdal$ ogr/ogrinfo -ro PG:dbname=test
-sql "SELECT gid,name,recnum FROM point" -so
INFO: Open of `PG:dbname=test'
      using driver `PostgreSQL' successful.

Layer name: sql_statement
Geometry: Unknown (any)
Feature Count: 53
Layer SRS WKT:
(unknown)
gid: Integer (0.0)
name: String (0.0)
recnum: String (0.0)
mloskot at dog:~/dev/gdal/_svn/trunk/gdal$


In case 2., default value (254) is used, that's why you get
varchar(254).

I'd recognize it as correct and expected behavior of OGR,
although a little strange or even surprising :-)


p.s. I added gdal-dev at lists.maptools.org to CC

Cheers
-- 
Mateusz Loskot
http://mateusz.loskot.net
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