Re: [udig-devel] handling GML files with uDig?

[Jody Garnett <jody.garnett@xxxxxxxxx>]

Jody,

I'm picking up the thread below, because I've bumped into some problems

using the geotools GML library for parsing GML files, and I got no

response from regarding this issue on the geotools mailing list. As you

suggested to use geotools below, you might have more insight into this.

No worries; it is sometimes easier to start with running code when asking for help. I always start with the test cases.

I'm trying to go through the code samples privded here:

http://docs.geotools.org/latest/userguide/library/xml/geometry.html

in particular, the GML3 parsing code sample, and when running the code,

I get the following warnings, during the call to

gml.decodeFeatureCollection():

There are a couple different options on that page; setting up your configuration by hand gives you the most control. I tried to make a GML utility class to support the most common configuration - but I am not sure it is working out in practice as GML schemas require so much setup.

Nov 25, 2011 1:01:30 PM

org.geotools.feature.simple.SimpleFeatureTypeBuilder add

WARNING: Creating location with null CoordinateReferenceSystem - did you

mean to setCRS?

Nov 25, 2011 1:01:30 PM

org.geotools.feature.simple.SimpleFeatureTypeBuilder add

WARNING: Creating geom with null CoordinateReferenceSystem - did you

mean to setCRS?

this is despite the fact that I have called

gml.setCoordinateReferenceSystem() earlier - see the complete code

sample at the end of the e-mail.

I wonder if it is the GML file not having an srsName element? The problem may be the file and not your code...

looking at the source code of GML.decodeFeatureCollection() in the

geotools-8.0-M3 codebase, I find that indeed, the while

gml.setCoordinateReferenceSystem() sets the crs property in the GML

object, the decodeFeatureCollection() call does not use the crs property.

Ah interesting; we should make a bug report (especially if you have sample code). 

am I doing something wrong here? what would be the proper way to parse a

GML file?

 There are a couple of examples on that page; mostly I have taken them from the JUnit tests for the different GML parsers. 

I suspect you have found a bug in decodeFeatureCollection rather than doing anything wrong.

PS: the code I used was the following, based on the code in the

documentation page:

File file = ...

InputStream xml = new FileInputStream(file);

GML gml = new GML(Version.GML3);

gml.setCoordinateReferenceSystem(DefaultGeographicCRS.WGS84);

simpleFeatureCollection fc = gml.decodeFeatureCollection(xml);

the test data I used is the three point test GML3 data found in the

documentation page

You may wish to try further down that page where they set up a parser configuration by hand. I try to do the right thing in the GML utility class you mention; but I have not gotten a lot of feedback.

Jody