[talk-au] vicmap data licensing

Nick Hocking nick.hocking at gmail.com
Sat Oct 12 02:26:33 UTC 2013


Hi Li

I'm convinced that you will find that it is practically impossible to mass
import (or even mass merge) a new road dataset into existing data when
there is a large amount of existing data. The only practical way would be
to delete all of the Victorian data and start again with the mass import.

This would destroy OSM Victoria.

Using high quality external data to complete the existing data is a
realistic and not to difficult job. Firstly any existing roads that lost
their names in the licence change (or had only ever been traced rather than
surveyed in the first place) will appear highlighted in OSMI and can easily
be named using vicmap data by any number of armchair mappers. This is an
easy and enjoyable task.

Also the vicmapdata will probably have a lot of roads that are new or that
have never been traced or surveyed in OSM.  These can easily be identified
by overlaying  the vicmap data in one JOSM layer and the existing data in
another. Using correct transparency and colouring the new roads stand out
like.....oops.

Then the vicmap data (on a road by road basis) can be click selected and
merged into the existing layer with all its tags. If a whole neighbourhood
is new then it may be merged as a unit. You will have to manually connect
the new road/s to existing ones but that is also easy. Bing imagery (which
is very good in Australia) can aslo be used, at the same time, to verify or
tweak the vicmap data as it is manually merged. All this results in
excellent road data which will be better than any other prroviders, by a
wide margin.

I do this every year that new TIGER data comes out and I make sure a few
cities in the USA are updated in this fashion. Every time vicmap produce
new datasets this process can easily be repeated, without having to do a
whole new mass import. Of course, ideally, local mappers will have surveyed
any new roads way before vicmap have produced a new data set. This
certainly happens in Canberra - which reminds me, there may be three of
four new roads open today - I'll go have a look in a minute or two.

Given the current amount of good quality existing Victorian road data in
OSM, the task of getting it perfect using vicmapdata will not take too long.

Of even more use would be if there is cadastral data available.  This is
absolutely essential if OSM is to ever succeed and this data is not easily
surveyed. Walking around with a pad an pencil peering into people's
letterboxes or doors is not safe or enjoyable. Therefore this data is ideal
to be mass imported. (especially as it would probably be high quality data).

Even then you would have to be careful not to "step on peoples toes" who
had already done a street or two.  Maybe you could import address info on a
street by street basis and if your import program found any existing
address data, it could ignore that street and create a list somewhere that
people could use to do a partial manual import from vicmap data.   How you
programmatically compare streets in OSM and Vicmapdata is the difficult
bit. No one in OSM has ever been brave (or maybe clever) enough to achieve
this yet and I certainly couldn't.
Mass imports only can work if there is no (or almost no) existing data. USA
found this out when the mass import of TIGER data, effectively destroyed
the USA OSM community and it has taken nearly ten years to recover.
Unfortunately the original TIGER data was/is very low quality in terms of
geometry and this still plagues the USA data to this day (and probably for
the next 5 years or so).

I'm sure that people in OSM-US can help in converting vicmap data into an
imagery layer (and may even host it for you as well :-)

Cheers
Nick
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