SPASE - XML Validate Tool
Space Physics Archive Search and Extract (SPASE) Consortium
SPASE metadata validator Using schema: http://www.spase-group.org/data/schema/spase-1_2_0.xsd

Enter the URL or local path to the SPASE description, then click "Validate".
You can also select the version of the data model to use.

URL: 
-or-
File: 
   SPASE Data Model Version: 1.3.0 (draft) 1.2.1 1.2.0 1.1.0 1.0.1
Start over... Download source and documents...

Try some examples:
WindWavesTNR.xml (version 1.0.1 compliant)
WindWavesTNR.xml (version 1.1.0 compliant)
bad-WindWavesTNR.xml (will produce an error)
CL_SP_PEA_SPASE_V1_0_1.xml (version 1.0.1 compliant)
bad-CL_SP_PEA_SPASE_V1_0_1.xml (will produce an error)

This validation service uses XML schema and Java to perform the validation. If you're interested in all the details, including documentation on this application, you can download entire package. You will also need servlet.jar from Sun and the UploadBean from JavaZoom.

You can run a validation on the command-line using:

java -cp validate.jar spase.bean.Validate xmlfile

which will validate the xmlfile using the schema for the current release of the data model available at the SPASE web site. If you are not connected to the web you can also supply the XML Schema document as the next argument. In which case the command will look like:

java -cp validate.jar spase.bean.Validate xmlfile xsdfile

You can download XML schema defnitions from:

http://www.spase-group.org/data/schema