[talk-au] Way errors in Quilpie Qld

Andrew Davidson theswavu at gmail.com
Sun Oct 3 01:58:02 UTC 2021


On Sat, Oct 2, 2021 at 10:46 PM Thorsten Engler via Talk-au
<talk-au at openstreetmap.org> wrote:
> I would assume that the lot boundaries recorded in DCDB are "exact" and any
> discrepancy between them and the physical world come down to the margin of
> errors the surveyors did when placing boundary pegs at some point.

I tried to check against any survey marks that you might be able to
locate on the imagery. Unfortunately there are no survey marks in
Quilpie from the GNSS era of surveying. I did manage to find one near
town that you can just make out where it would be on Bing:

https://qspatial.information.qld.gov.au/SurveyReport/SCR183342.pdf

> Bing is almost right: -0.15; 1.79

I get -0.10;1.50 which, considering that we are looking at aerial
imagery with a pixel size of ~0.15m, is the same thing. This is all
based on GDA94, so in theory all of the GPX traces will be offset by
about 1.63 m

I have done a best-fit and moved the town about 11 m to the west.
There are some things (e.g. the rail line near the sale yards) that
need to be better traced. I will have a look at these later.



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