Purpose and Scope

The Area Features schema includes information about area features such as environmental areas, soils, wetlands, land use, flood plains, site improvement areas, right of way, and cadastral information.  Of primary concern to the designer is the location of these areas with respect to the roadway project being designed.  This information is typically held in a GIS but would be helpful if it could be included as a backdrop to a CAD design drawing.

Currently LandXML includes land parcels as the only area features and it approaches these from the perspective of surveying.  A more general purpose area feature capability is needed by TransXML to support the transfer of such information from agencies outside of the design office, such as planning, National Wetlands inventory, counties and municipalities, FEMA, right of way, soils, and consultants.  As this is currently outside of the scope of LandXML, minimal interaction with LandXML.org is anticipated.

Area features are common to most GIS software and have been standardized by ISO TC211.  We would use these as the basis for the development of this schema.  The LandGML Interoperability Experiment surfaced the problem of different representation schemes for triangulated surfaces in CAD vs. GIS software packages and standards.  It will be necessary to investigate the differences between GIS and CAD area feature representations to see if similar problems exist.  If existing GML subschemas satisfy the design need, they can be included under the TransXML umbrella as is.  Otherwise, alternative schemas may need to be proposed.

Base Schema/ Standards

Existing schema and/or standards that this will be based on include:

·         LandXML 1.0

·         LandGML

·         ISO TC211 19107 Geographic Information – Spatial schema

Resource Documents

·         Crews, N., E. Hall, and D. Rebolj, LandXML Schema Version 1.0 Reference, 2002.

·         Crews, N., LandXML-1.0.xsd

·         Burggraf, D., LandGML0.6.xsd

·         ISO, ISO/TC 211/WG 4/PT 19136 Geographic information – Geography Markup Language (GML), ISO CD 19136, February 7, 2004.

·         Ron Lake, David S. Burggraf, Milan Trninic, and Laurie Rae, Geography Mark-Up Language, John Wiley & Sons, Inc., San Francisco, CA, 2004.

·         ISO 19107, Geographic information — Spatial schema, International Organization for Standardization, Geneva, 2001.

Sample Applications

Proposed applications to be developed to demonstrate the use of this schema:

·         Display area features from GIS into MicroStation using MDL or VBA.