GeoRSS Formats (part 2 of 3)
There are currently three format options for tagging location data to GeoRSS files: W3C, Simple, and GML. http://www.georss.org/index.html is an excellent resource and describes these GeoRSS formats in greater detail.
- W3C is the most basic of the GeoRSS formats and is only capable of describing point features (no lines or polygons). W3C GeoRSS geographic coordinate tags allow two syntax options:
The more nested version looks like this:
And since Point locations are the only type of geometry supported by the W3C format, those more prone to brevity might prefer:
- Simple GeoRSS enables items to be tagged with not only point locations, but also lines and polygons. This is the GeoRSS format that IDV Solutions‘ applications generate. Here is what they look like…
Simple GeoRSS point geometry (order is important –first latitude then longitude):
Simple GeoRSS line geometry:
Simple GeoRSS polygon geometry:
- GML GeoRSS is a more verbose but expressive format. GML allows for more complicated geometries, like polygons with doughnut holes (for example, the state of Florida could have Lake Okeechobee punched out of it). This format is rarely used at IDV because it is not as common as W3C or Simple GeoRSS formats. Check out www.georss.org/gml.html for some syntax examples.
W3C and Simple GeoRSS formats assume a WGS84 datum reference for their Latitude/Longitude coordinates. GML provides a means to define a different datum.