[mapserver-users] PGeo (Personal Geodatabases) options under Linux
Fawcett, David (MPCA)
David.Fawcett at state.mn.us
Mon Nov 30 14:06:21 EST 2009
I think that the more important question than, "can I get MapServer to use the personal geodatabase?", is, "what data source will support the efficiency/optimization that my project requires?"
Even if you can get the personal geodatabase to work, it may be that it won't perform to meet your needs. Regardless of the data format that data is acquired in, it is often recommended to convert formats or modify the data to optimize it for a Web app. Everything that can be pre-calculated, pre-sorted, indexed, etc. before the user clicks the button will make the Web app faster. The vector data optimization page is a little lean, but it is here: http://mapserver.org/optimization/vector.html
I am thinking that even if you can get MapServer to read the personal geodatabase, you will want to convert it to shapefile (or PostGIS if you need the relational database).
You can then add spatial and attribute indexes, pre-calculate symbol classes, create a tileindex if needed, etc.
You have to love government agencies that distribute in proprietary file formats!
From: mapserver-users-bounces at lists.osgeo.org [mailto:mapserver-users-bounces at lists.osgeo.org] On Behalf Of Chuck Jungmann
Sent: Monday, November 30, 2009 11:47 AM
To: Dan Little
Cc: mapserver-users at lists.osgeo.org
Subject: Re: [mapserver-users] PGeo (Personal Geodatabases) options under Linux
Responding to both of your comments:
My client regularly acquires a database of property maps from a county.
The database is a ESRI Personal Database. An employee of my client has
been converting this database (and others like it) to MapX files for
running on MapXtreme (on Windows, as you observed). I understand it to
be a rather involved process.
On the subject of creating a shape file from the PGeo file: one of the
layer tables has almost 200,000 records. That's just for the parcel
outlines. I also would need to add the text labels and other outlines as
well. That would make for an unwieldy shape file. In fact, I think
that employee mentioned above actually does combine the shapes into 9
MapX layers that I have been combining for display. The combined MAP
files come to 221.3MB, and 351.6 MB for all layer files.
I am exploring the possibility of delivering the same web application
using open source software, including MapServer, on Linux. I was hoping
to use the database as delivered, because it would save time and
Although it looked like it should have been possible to display layers
from the PGeo file, I haven't had any luck. I have spent a lot of time
trying to figure out if I could apply some patch, looking for
insufficient buffers that I could lengthen, etc., but have pretty much
come to the conclusion that using PGeo files is perhaps only feasible on
MapServer for Windows, where there is native support for the MDB files.
I originally asked the question because
1. I didn't want to give up too soon if someone has had some success
using unixODBC and MDBTools, and
2. I wanted to know if making an exact copy of the PGeo tables in a
MySQL database would allow me to use PGeo to access the layers. This
seems feasible since both MDBTools and MySQL can be accessed through the
It would be nice if OGR wouldn't know the difference between MDB and
MySQL databases because I could then run a script (that I'm working on
now) that would run on Windows to make a restore file for MySQL to
import the data. I hope to finish the script today or tomorrow. If it
works as I hope, I'll report it here since it would answer the second
Assuming success using MySQL, the first question is moot: MySQL would be
a much more robust solution. If I can make a turnkey conversion from
MDB to MySQL, it's really a no-brainer to abandon MDB. But I'm still
curious, and it would be nice to document somewhere online, if it's
possible to use PGeo files on a Linux-based MapServer.
On Mon, 2009-11-30 at 05:59 -0800, Dan Little wrote:
> I am making the gross assumption that someone, who is producing the PGeo file is on Windows and that person(s) would be available to do the conversion...
> ----- Original Message ----
> > From: Stephen Woodbridge <woodbri at swoodbridge.com>
> > To: Dan Little <danlittle at yahoo.com>
> > Cc: Chuck Jungmann <chuck at cpjj.net>; mapserver-users at lists.osgeo.org
> > Sent: Sun, November 29, 2009 10:22:37 PM
> > Subject: Re: [mapserver-users] PGeo (Personal Geodatabases) options under Linux
> > Dan Little wrote:
> > > not that this answers the problem... but is there any reason this
> > > cannot be exported to a shapefile and then served with mapserver?
> > Good question. I think you would have to do that on a Windows box because the
> > MDBTools on Linux is just not up to the task. If you could export it on Linux
> > then you could also probably serve it directly via mapserver and ogr.
> > -Steve W
> > > ----- Original Message ----
> > >> From: Chuck Jungmann To: Stephen Woodbridge
> > >> Cc: mapserver-users at lists.osgeo.org Sent:
> > >> Fri, November 27, 2009 5:17:03 PM Subject: Re: [mapserver-users]
> > >> PGeo (Personal Geodatabases) options under Linux
> > >>
> > >> I've read that page several times. I have also built MDBTools,
> > >> unixODBC and GDAL from CVS sources and applied patches, etc, so I
> > >> could try to trace execution to the errors. What I've found are
> > >> instances where the code ultimately ends up in an empty function
> > >> that simply returns SQL_SUCCESS or SQL_OK or whatever without doing
> > >> anything. That seems to be why MDBTools has trouble with "SELECT
> > >> COUNT(*) FROM xxx" and why it can't find a primary key.
> > >>
> > >> While I can see that these database features are not working, it's
> > >> also possible that they are not necessary. I'm wondering if anyone
> > >> has had success, either despite these errors, or by not
> > >> encountering these errors, in which case I may find some success if
> > >> I can duplicate their environment.
> > >>
> > >> Thanks for the quick reply, Chuck Jungmann
> > >>
> > >> On Fri, 2009-11-27 at 18:00 -0500, Stephen Woodbridge wrote:
> > >>> Chuck Jungmann wrote:
> > >>>> I have a Personal Geodatabase (PGeo) from which I would like to
> > >>>> display layers in MapServer on Ubuntu 9.04. I have been
> > >>>> fighting with MDBTools, unixODBC, and GDAL for what seems like
> > >>>> forever. The ogrinfo and isql fail with Segmentation Faults.
> > >>>>
> > >>>> I have two questions:
> > >>>>
> > >>>> 1. Has anyone successfully used a PGeo file to display maps on
> > >>>> MapServer under Linux? Perhaps my efforts were doomed from the
> > >>>> start.
> > >>>>
> > >>>> 2. Since GDAL is using ODBC to read the MDB file, would using
> > >>>> ODBC to access MySQL be a transparent replacement, assuming I
> > >>>> copy all of the tables and indexes from the PGeo file to MySQL?
> > >>>> Has anyone done this? I don't want to waste a lot of time on
> > >>>> this if it's another dead end.
> > >>> Chuck,
> > >>>
> > >>> There was a recent thread related to these problems on the GDAL
> > >>> list. Frank posted the follow link and commented that there are
> > >>> also probable some open bugs. Evidently, the mdbtools are not
> > >>> well supported and buggy which makes using them problematic.
> > >>>
> > >>> http://trac.osgeo.org/gdal/wiki/mdbtools
> > >>>
> > >>> Check out this thread on the gdal-dev archives: [gdal-dev] mdb to
> > >>> shape conversion: no geometry exported
> > >>>
> > >>> -Steve
> > >>>
> > >> _______________________________________________ mapserver-users
> > >> mailing list mapserver-users at lists.osgeo.org
> > http://lists.osgeo.org/mailman/listinfo/mapserver-users
> > >
> > >
> > >
> > >
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