Georeferencing comparison page

Here is an example, well-defined coastal locality, Pipe Clay Lagoon in south-east Tasmania, Australia, from the ground (top), and with a location shot generated via the NASA "World Wind" application based on Landsat TM data and a digital elevation model (below). How can we establish a relevant georeference for this location (preferably without having to go down there with a hand-held GPS)?

Pipe Clay Lagoon, SE Tasmania, Australia
Pipe Clay Lagoon, SE Tasmania, Australia, looking east (photo: Tony Rees)

Pipe Clay Lagoon - location view
Location shot, generated via NASA "World Wind" application (north is at top; labels are a manual addition)

The image accessible via this thumbnail shows a portion of the relevant 1:50 000 (coastal) navigational chart, which permits the locality name "Pipe Clay Lagoon" to be associated with a recognisable coastal feature:

Navigational chart - thumbnail (click to enlarge)

First, using a couple of on-line gazetteers, we can get the following results by querying on the locality name: Second, providing that we can recognise the feature from its shape and its position relative to other recognisable features (or the general lat-lon grid), we can apply manual georeferencing using a tool such as NASA's "World Wind", or "Google Earth": The Google Earth value is virtually identical to the NASA World Wind value (which probably reflects the fact that they are using common Landsat imagery as a topographic basemap) and very close to the other gazetteer values in this example, though with improved precision, i.e. to the nearest 0.1 minute rather than full 1 minute. However since the maximum (N-S) length of this feature is around 2 minutes of arc (approx. 3.5 km) and we have not stated any more precise locality information than feature name, possibly such improved precision is unnecessary in this case. We are also fortunate that, in this example, (1) the locality name is well enough established to be recorded in at least one on-line gazetteer; (2) there are no other competing localities with the same name, to choose between; and (3) the locality is itself a marine feature, so that the relevant gazetteer values do relect the relevant "marine" portion of the feature name (often this will not be the case, for example a town may be referenced by its GPO or administrative centre rather than its nearest beachside or harbour location).

This site is hosted by the CSIRO Oceans and Atmosphere Information and Data Centre, Australia. Please advise any problems with this website to the OBISAU Node Manager.    View Privacy Statement