The map images on the DVD are digital scans of DLIs and Geoscience Australia’s (Royal Australian Survey Corps) 1:50,000 topographical and cadastral map series that covers part of South West W.A. Where available, the DLI’s Topo/Cad maps (with 10m contour intervals) have been used but in areas where no coverage from this series was available, the RASC maps were used. The Survey Corp maps do not show cadastral (land boundary)data and have 20m contour intervals shown.
The maps have been scanned at 200dpi and the resulting images supplied on the DVD in two formats, OZF2 and ECW. The OZF2 images retain the original resolution while the ECW format files have been compressed and some clarity is lost. OZF2 images can only be used with OziExplorer (full version) and OziExplorerCE while the ECW files can be used with these and a variety of other navigational programs such as TrackRanger.
Each map sheet generally covers an area of 15' longitude by 15' latitude which corresponds to approximately 25km x 25km. Some combined sheets cover a slightly larger area.
The date when the original maps were first printed varies considerably but ranges from about the late 70’s to the late 90’s. Some are now out of print and unavailable for purchase. The maps are the most detailed available in digital raster format over this entire area and show all significant natural features (lakes, swamps, rivers, creeks, hills, coastal features etc) along with cultural features (tracks, roads, highways, towns, dams etc ) present at the time the data was collected for use to draft the maps.
This disc comes with ER VIEWER (by Intergraph), a free desktop image viewer that allows you to open and view the supplied ECW map files on your computer. The program provides a coordinate readout in either decimal degrees to two decimal places (for maps calibrated using Latitude and Longitude) or in metres to two decimal places (for maps calibrated in UTM). Distance measurement is also available for UTM maps.
For a more accurate co-ordinate readout, and access to features such as moving map, track and waypoint creation, a compatible map viewing software such as OziExplorer or TrackRanger is required. These programs are not included on the disc and must be obtained separately, possibly at additional cost. It should be noted that free demo versions of some programs are available. Some of these can be used to at least view the maps. See individual software makers websites for details.
Relating to Use with OziExplorer or TrackRanger GPS Mapping Software - Calibration files are included on the DVD so users can start using the maps immediately. Calibration data is also supplied within the ECW files allowing geo-referencing data to be displayed while using other ECW viewing software (such as the ER Viewer supplied on the DVD or ArcView) but the accuracy of this information is much lower than available when using OziExplorer.
Digital elevation data is supplied on the DVD. This information can be used to create 3D map images using OziExplorer3D. Elevation data is at 3 sec (90m) intervals and is the most accurate available over such an area.
A place name database for use with OziExplorer is also provided allowing users to search for the location of named features that occur anywhere in WA. In addition a smaller scale map of SW WA is included and is suitable for use as an index map in OziExplorer.