Author: Lee Belbin, 2019
The gazetteer generated for the Spatial Portal is a list of all ‘named locations’. The gazetteer in the Spatial Portal contains an amalgamation of three sources of information:
- The Gazetteer of Australian Placenames (http://placenames.fsdf.org.au/),
- All named polygons of the Spatial Portal’s contextual layers (http://spatial.ala.org.au/layers)
- Global Administrative Database (GADM: http://gadm.org).
Access to all these locations is via the Spatial Portal’s Add to Map | Area | Gazetteer polygon. Using this function will enable a search for a named location for any of the above datasets, and once selected, it will be mapped as an area layer of type = polygon.
The Gazetteer of Australian Placenames
The Gazetteer of Australian Placenames is currently the version published in April 2019 (with release date of June 2018). If you go to the gazetteer web site (http://placenames.fsdf.org.au/), you will see that all the locations are points, even when many of them may be better represented as areas. For example, “Royal National Park” (the world’s second National Park after the USA’s Yellowstone National Park) is an area that is represented by a point even though it is obviously an area. This gazetteer classes the feature as a “Locality”. When using the Spatial Portal’s Add to Map | Area | Gazetteer polygon with locations from the Gazetteer of Australian Placename, you will be asked for a radius around the point location so that a circular area (a polygon) is created, rather than simply a point.
If a location does not have a name in our gazetteer, you can still create an area using one of the Add to Map | Area options:
- Draw bounding box
- Draw polygon
- Draw point and radius
- Create radius around point (provide latitude and longitude)
- Import the definition of an area from a Shapefile, a KML file or WKT (Well-Known Text)
- Define environmental envelope (define an area from a range of environmental values)
You can get another idea of the use of the Gazetteer of Australian Placename by using the Spatial Portal’s Tools | Nearest locality. Zoom and pan the map to an area of interest and then select Tools | Nearest locality from the menu and then click on a location on the map and you will see something like Figure 1 where the 10 closest locations from the Gazetteer of Australian Placenames mapped and listed in the legend. You can optionally download this list as a CSV file.
Figure 1. Named locations closest to a point on the map
Named polygons within the Spatial Portal’s contextual layers provides a useful way of defining an area that may correspond to a location or a region. For example, “ACT” will map both the polygon around Canberra and Jervis Bay.
You can also get more sophisticated such as using a class within say the layer called “Dynamic Land Cover”. Try typing “Open alpine” into the search in Add to Map | Area | Gazetteer Polygon and you will see an entry more fully described as “Primarily vegetated Natural and Semi-Natural Terrestrial Vegetation Herbaceous Graminoids Open Alpine”. If you map this area, you will see it is comprised of multiple polygons that together define a unique type of alpine vegetation, which, naturally enough, is restricted to Australia’s alpine areas in NSW and Victoria (Figure 2).
Figure 2. Open Alpine regions
Global Administrative Boundaries
The third component of the Spatial Portal’s gazetteer are country boundaries areas sourced from the Global Administrative Database (GADM: http://gadm.org). Using the Spatial Portal’s Add to Map | Area | Gazetteer polygon search, these will be displayed as “World Country Boundaries”. All administrative areas/jurisdictions with the Spatial Portal’s gazetteer below country level (except Australia itself) come from the contextual layers such as “Local Government Areas”, “Statistical Local Areas” and similar. See Figure 3.
Figure 3. Using GADM to map country boundaries