NT geo-referenced digital maps

SA, WA & NT specific bushwalking discussion.
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NT geo-referenced digital maps

Postby Off-track » Sat 13 Jan, 2018 10:11 am

While planning a trip to the NT around Kakadu NP (mostly driving, with some on-track walking) I was searching for maps to use off-line in Oruxmaps.

From what I can see, the NT government wms capability does not yet extend to topographic maps. The best I could find were 1:250,000 georeferenced pdf mapsheets from Geoscience Australia and OpenAndoMaps vector map and poi files for the NT. Both work well in OM: the 1:250,000 mapsheets are better for low zoom work (driving) and OpenAndroMaps are better for high zoom uses (walking tracks and detailed street layouts with key facilities from the poi file).

Theoretically there is a wms server for the GA 1:250,000 mosaic, but it did not work for me. I used the Darwin, Pine Creek, Alligator River and Mount Evelyn geopdf mapsheets. GA keeps changing web links, so those from third parties (and some within GA) may be dead. Try searching (mapname 250 topo) from:- http://search.ga.gov.au/search.

There is a map index at:- https://data.gov.au/dataset/printed-topographic-map-index-100k-250k. You can download (large) tif files of 1:100,000 topographic maps from GA but I do not think these are geo referenced. The 1:50,000 topographic maps of this area appear to be available only on paper.

Open AndroMaps came from:-
https://www.openandromaps.org/en/downloads/australia-newzealand-oceania.

Does anyone have suggestions for other geo-referenced digital maps of the Northern Territory that may be better for walkers?
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Re: NT geo-referenced digital maps

Postby Off-track » Sat 03 Feb, 2018 9:42 am

Another option is OSMand with the contour lines plugin (both available free from F-Droid, then you can donate if you find them useful). The contour data (and hill-shading if you wish) are available in separate downloads by region (e.g. Northern Territory) from within OSMand once you view an area of interest and go to configure map > contour lines. Once downloaded (typically by wi-fi to avoid data costs) all the maps and data are stored in your device for off-line use. OSMand gives very good road navigation with turn-by-turn voice guidance, and it is useful for mild off-track excursions with the OSM background map and 10m contour layer. Waterways are not very accurate in OSM (by design), but in some areas walking tracks are very well represented.

This approach is not NT-specific (I have also used it in PNG where there seems to be a similar dearth of wms topo maps). OSMand is excellent anywhere as an off-line road navigator with voice guidance. For hiking, I prefer high-quality 1:25000 topo maps where they are available in geo-referenced pdf or wms form (for use in oruxmaps or the like).
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Re: NT geo-referenced digital maps

Postby Warin » Sat 03 Feb, 2018 11:29 am

Off-track wrote:Waterways are not very accurate in OSM (by design),
:?:

Within OSM waterways have the same method of storage as anything else - so the same level of 'accuracy' is avalible.

They can be 'accurate' .. just that not many people have GPS traces for them .. as in they don't 'walk/drive' them. And then there is 'where is the center?' problem - equal distance from both banks or deepest part?
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Re: NT geo-referenced digital maps

Postby Off-track » Wed 28 Feb, 2018 12:17 pm

This is off the original topic, but waterways tend to have more twists and turns than roads. I have mapped some waterways accurately and put the traces in OSM, but within a short while the accuracy is substantially reduced by 'automated' reduction of the number of waypoints, resulting in substantial reduction in accuracy of the waterway path relative to other common (e.g. topo) maps. The roads in OSM are as accurate as the topo maps, but the waterways are far less accurate.
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