What is a GML file?

A GML file format — also known as a Geography Markup Language format, as defined by the Open Geospatial Consortium (OGC) — is an interchange format for geographic transactions across the internet. This format is similar to XML, but is optimized towards the expression of geological features and is often used for webservice data calls (API). Spotzi recommends using GML and KML formats for geographical purposes; the XML format is only sufficient when working exclusively with data.

GML file structure explained

A complete GML dataset contains the following specifications:

• The first section contains information about the GML data format.
• The second section contains information about the coordinates within which the map appears (known as the bounding box).
• The third section contains information pertaining to the dataset.
• The fourth section contains the geometry necessary for placing all of the map's features on the map.
• The fifth section contains the opening tags which offer more information about specific map features (points, lines or polygons).
• The sixth section contains closing tags.

Which software opens GML files?

• QGIS
• Arcgis
• Mapinfo

Associated filename extensions

• .xml
• .kml
• .gml