All vector data ought to be geometrically valid without exception. “Valid without exception” means that the PostGIS v 1.3.2 function isValid() returns 'true' on all features in all datasets. We are particularly concerned for this because PostGIS induces more stringent validity than many processing elements, and it would be unfortunate to bring data any ways along a chain of processing only to discover at some point that it is less useful than it ought be. If it is valid in ArcView, it should be acceptable.

Metadata is data about how the data was made and the source of the data. All of this metadata ought to be valid ISO 19139 metadata. “Valid” means schema-valid according to the ISO TC 211 schemas at:

http://www.isotc211.org/2005/gmd/

specifically

http://www.isotc211.org/2005/gmd/gmd.xsd

with root datatype {http://www.isotc211.org/2005/gmd}:MD_Metadata and appropriate values for mandatory elements and attributes.

If controlled vocabularies are in use for metadata, they ought to be explicitly defined or referenced in each piece of metadata wherein they are used. ISO 19139 provides quite specific and simple ways of so doing.

Vector data ought to be provided as ESRI Shapefiles with UTF-8 character encoding for attribute tables and vector data in WGS84.

Attribute tables ought not include empty or default-valued fields.

Projection files that accurately reflect the data ought to be included. Metadata ought to be included in the usual xxx.shp.xml file.

Raster data ought to be provided in Geo-TIFF file, or TIFF form in WGS84 with accompanying World file and accompanying ISO metadata as described above.