Fair Insight Rule - Check For Direct Links to Data

This FAIR Insight rule checks that links to a zip file contain geospatial data.

This Insight rule gets the last 100 bytes using an HTTP Range request to read the end-of-central-directory (EOCD) section in a target zip file. The EOCD section contains a complete file listing and file byte offsets in the ZIP. File listings are then verified to have a geospatial extension.

Recognized File Extensions

  • gpkg

  • shp

  • gdb

  • geojson

  • kmz

  • kml

  • gml

  • gpx

  • vct

  • tab

  • osm

  • dlg

  • img

  • asc

  • tif

  • rst

  • pix

  • ecw

  • jp2

  • sid

  • mdb

  • mbtiles

  • vmds

  • sqlite

  • las

  • laz

  • xyz

  • dem

  • hdf

It is important to note that enabling the HTTP Range header is completely optional for caching data in Geoplatform.

Besides enabling Range header on the server, some other reasons this rule may fail:

  • No ZIP64 support

  • No encrypted ZIP support

  • No stream support

  • Long comments in a ZIP file

ISO 19115

//gmd:transferOptions/gmd:MD_DigitalTransferOptions/gmd:onLine/gmd:CI_OnlineResource/gmd:linkage/gmd:URL/text()

More Information

FGDC Technical Guidance: Data.gov and The GeoPlatform Metadata Recommendations HTTP Range Header HTTP Range request