OGP releases standard map shapes
Saturday, April 14, 2012
The European Petroleum Survey Group (EPSG) of the International Association of Oil and Gas Producers (OGP) has released a series of standard map 'shapes', or 'polygons', which can be used to together with maps.
It is conventional to use square or rectangular "bounding boxes" with maps, but the boxes cover a much bigger area than the area of interest, which can lead to inefficiency when searching data.
For example, see the image of the North Island of New Zealand (above). The map can have a conventional bounding box (shown in red), or a "polygon" or shape bounding box (shown in yellow).
If only data relating to onshore is required, it is more efficient to specify that you would like data within the yellow bounding "polygon" than the red bounding "box".
'We anticipate that the polygon data will be used through the mapping capability of GIS applications and web sites offering a map front end for searching the EPSG Dataset," says Roger Lott, chairman of OGP's Geodesy Subcommittee.
The polygon data has been captured at point densities suitable for small scale mapping.
It is being distributed in both GML and Shape file formats.
The data is available for download from the OGP Geomatics Committee website at http://info.ogp.org.uk/geomatics/polygons.
In due course, the data will be incorporated within the EPSG on-line registry.