Monday, Dec 09, 2019 at 13:32
Greg,
Your comments are correct relevant to the 250K original GoeScience data produced to a raster map sheet however our current dataset are very far removed from the original sources. We have spent many day, weeks, months and years sourcing and in some cases manually rebuilding thousands of roads and positional elements.
But it also should be noted that positional extraction/use of data items from the original GeoScience 2005/2008 data-sets is very much different than looking at or reuse of the Raster product. Even though they had the same name and the Raster was derived/draw from the GeoScience NatMAP 250K dataset, the actual positional data for the POI type features was not out by much provided the Datum's were set/converted correctly. Though also GPS accuracy was not so good back then either so 50/100m differences are not uncommon.
I was puzzled at one point when I went back along a route I researched using OziExplorer and the Raster 2005 setup then went back with 3 devices running
ExplorOz Traveller and a much later version of Ozi and found the positional data I had recorded was all out by about 150m however the road lines I had draw were spot on - this was a very strange circumstance and is still a mystery to me, I double checked even the old setup to see what had happened but it does seem like a Dataum problem for the positional entries that did not effect the road lines (why still a puzzle). But having said this all the data has again been updated and is now correct again.
I am sure as we continue to move forward accuracy will get even better and couple this with the massive investments being made in the new Australian Positional Data Framework by GeoScience and the GDA2020 datum - from their
Datum Modernisation in Australia projects. We will continue to improve and update our data as part of of major on-going projects in this area.
Regards
David
Now to find out from the OP what the issue he is seeing!
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