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Re: [udig-users] GeoDB file Data Formats and uDIG
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Shaun Kolomeitz wrote:
Dear fellow uDIG users,
I've had no luck from the uDIG devel list so I thought I'd see if users could maybe provide some advice or pointers on an issue I am trying to resolve.
I'm in the final stages of investigating the options for using an open source GIS product for over 600 clients. The options are now uDIG, QIS, gvSIG. uDIG has some appeal being a Java custom client over a C++/C# client.
It would be good to set up a conference call to go over your options
with respect to uDig.
Really we're only after a basic map interface with a lot of custom dynamic forms to capture data, print maps and reports (PDFs). Not rocket science by any means.
Sounds great; the tutorials source code includes a "Feature Editor"
example showing how to make a custom form.
I'm pretty happy with the way uDIG is progressing and the features that you get "out of the box". In the back end however I am wondering what format will help us to manage a file-based geodatabase type structure ? I am after a structure similar to shapefiles with "related" DBF's, and unfortunately we cannot have PostGIS running, just a set of files.
I understand that this sounds like a pretty normal requirement from a
database / computer-science background; I have found in GIS that the
vast majority of data sets are really very simple. You will notice that
GML is proving less popular than shapefiles and KML for example.
Will GML "do it for us"?
I would love to say that GML would "do it for you", but GML is an
"interchange" format designed to communicate data between different
systems; it is not really set up for fast access. While we have been
able to do some really neat things using GML2 and a Web Feature Server
we are depending on the fact that the WFS is storing the data in a
useful database, and simply asking it to provide us the results in GML2.
The Shapefile format doesn't cut it for us because we have a need for long-text (memo) fields and one to many relationships in the data.
Can anyone suggest a format that we should look at (or is anything on the horizon like SQLite spatial, H2, HSQL ???) ? I notice that GeoServer uses a H2/Java db for the EPSG tables, but can you do a similar thing for uDIG ?
Yes you can - the DataStore implementation for H2 is here:
- http://svn.geotools.org/trunk/modules/unsupported/h2/
The implementation does not support relationships right now; but I would
love to add that ability (in terms of the feature model they are
represented as "Associations").
On the uDig side what is needed to hook that up to uDig is a couple of
classes, but we can go over that on the devel list. Depending on your
needs you may be able to get away with having just your application know
about the relationships, depends on if you need to use that information
when rendering?
The use of HSQL, and H2 to store the EPSG tables is a separate problem;
what is being stored in is CoordinateReferenceSystems rather than
features so we don't have the requirement of storing Geometry.
I've also got a much larger spec for the system if anyone is interested in discussing what we require and what might be suitable.
I would certainly be interested in learning more about your project,
does the idea of setting up a quick conference call have any appeal?
Jody
