Version 1.0 has been approved for use by the NGDS working group.

This information exchange specifies content elements for an interchange format for linear spatial features representing contour (isoline) data. These lines connect locations registering the same value for some variable. Examples include structure contour maps that represent lines of constant elevation on some surface, or gravity anomaly contours that represent lines of constant anomaly value. Fields in the content model will become XML elements in interchange documents for WFS simple features served by geothermal data web services.