There are several types of Geography Markup Language, or GML data:

 

• Simple GML
• CityGML
• INSPIRE GML

 

As time and technologies improve data providers are publishing more advanced GML formats and variants.  To import the INSPIRE GML format you currently need to use the FME Interface provided by OpenCities Map.  Use of this interface requires an active license of the FME Desktop software.  Please refer to the OpenGIS website for complete details about the GML format:

• The OpenGIS® Geography Markup Language Encoding Standard (GML) The Geography Markup Language (GML) is an XML grammar for expressing geographical features. GML serves as a modeling language for geographic systems as well as an open interchange format for geographic transactions on the Internet. As with most XML based grammars, there are two parts to the grammar – the schema that describes the document and the instance document that contains the actual data.

 

When the schema is missing, or present but not well-described the data may not import properly. This is apparent in the messages that are returned from the Import command. Some examples are shown here:

 

• Exception: The 'http://www.w3.org/XML/1998/namespace:lang' attribute is not declared.

• System.Xml.Schema.XmlSchemaException

• System.Xml.Schema.BaseProcessor.SendValidationEvent(XmlSchemaException e)

 

The FME Interface is accessible through the File | Import | FME menu item, as-shown here in the V8i menu:

 

For OpenCities Map, use the File | Import | Geospatial File Types | FME Import option

 

 

This short video shows the comparison of importing an INSPIRE-formatted GML file using the Import GML file command, vs. using the same file with the FME Interface:

 

* As of this writing, Enhancement 677540 had been filed to include the INSPIRE GML format as an option in OpenCities Map.  You may show your support for this enhancement via the OpenCities Map Ideas Portal.