On 14/5/23 09:47, cleary wrote:
I agree with much of what you wrote, but not all. Your final sentence implies
that you think that where OSM and the DCS NSW Base Map are different, then the
latter must be correct and OSM wrong. I have been frustrated when I have
visited locations and mapped features such as road names or road class
(secondary/tertiary/unclassified etc) noted during my survey and then have
someone change my contributions because they were contradicted by the DCS NSW
Base Map. When I have subsequently investigated (usually by revisiting the
location or by contacting the local council), I have found that the DCS Map
contained outdated information that had not been updated - sometimes for many
years. I think I did previously mention the OTC Overseas Telecommunications
structure at 744 Carnarvon Highway at Moree - still on the DCS Base Map more
than 30 years after it was decommissioned and the building re-purposed. Some
things just do not get updated on the DCS Map.
As I once mentioned on talk-au, when I visited Lake Mungo, the indigenous guide said that
the lake had not been covered with water for about 15,000 years. My subsequent reading
supports that claim. Nevertheless, DCS Base Map shows it no differently to lakes that are
always full of water. I have come to see the DCS NSW Base Map as generally more accurate
in "legal" matters such as surveyed land lots, boundaries etc but I would
suggest that OSM can do a lot better in mapping natural features such as lakes, wetlands,
and various forms of land cover.
I agree that the DCS NSW Base Map is a wonderful resource and has been very
helpful. However it contains errors. It should not necessarily be considered as
more authoritative than other sources, especially survey by individual mappers.
I value the DCS NSW Base Map but, if there are differences in information, it
should not be presumed that the DCS Map is to be preferred.
I should have said .. where I come across a difference I usually either
contact the mapper or seek another source.
I have found mappers generally like to keep their idea of the land cover
rather than the DCS one. Not something I am going to fight over. If
someone wants to map a flood plain (DCS) as a swamp in OSM .. well it
does render. Looks very pretty.
For other things I usually find another source, some times it confirms
the DCS sometimes not .. sometimes the other source is not clear...
On Sat, 13 May 2023, at 4:52 PM, Warin wrote:
In defense of the NSW DCS Base Map? Some have criticized the DCS Base
Map .. a response below.
“We don’t want OSM to be a copy of the DCS Base Map”? Umm OSM has
capability of far more than the DSC Base Map e.g. pubs, petrol
stations, farm fields, vineyards etc. So it should be far more than the
DCS Base Map. Where OSM is missing stuff that is in the DCS Base Map
why should it not be copied? That is a gain for OSM.
“The DCS Base Map is out of date”? So is the OSM data! I don’t see that
point of this ‘argument’ at all. If something in OSM is ‘out of date’
then correct it. If something is missing from OSM but is in the DCS
Base Map then copy it. Those who know it is out of date can correct it,
arguing that it should not be added because ‘it may be out of date’
could be applied to all sources other than those sighted in the last
day. Should any data that ‘may be out of date’ be rejected? I have
found some things in the DCS Base Map to be more upto date than the DCS
imagery having to resort to Maxar to confirm the existence of the
objects. So the DCS Base Map maybe ‘out of date’ for some things but
more ‘upto date’ for other things. Such are the joys of our changing
world.
“On the ground truth” Some take the view that they have been there and
seen X. Ok, the DCS Base Map says Y.. Humm. Where this is some land
form or land cover I take it the mapper involved has more expertise
than those that contribute to the DCS Base Map to determine that land
form or land cover. I would not put myself in that category. As an
example the ability to determine an area is an arid wetland, I have no
expertise to determined that and would take DCS Base Map as more
authoritative than my poor observations.
---------------
Me?
I have added libraries (those facilities that lend books) from the DCS
Base Map .. using a list from a copyright source to direct me to the
area and then searching the DCS Base Map for it. The location and name
comes from the DCS Base Map not the copyright source. This is not all
the libraries as some are ‘private’ e.g. schools. But it has got at
least most of the public ones into OSM. I call that a win for OSM.
Mangroves. These are well defined by the DCS Base Map. I have been
questioned as to how reliable they are .. well on 5 that I gone to
those all appear to be accurate .. and others can be seen on imagery.
So I am quite confident that these can be transferred from the DCS Base
Map into OSM.
And I have copied other stuff, missing in OSM, from the DCS Base Map.
There is a lot of it! I plan on continuing to do so. The DCS Base Map
is a great resource that we should use. I have even found errors in OSM
from the DCS Base Map.
_______________________________________________
Talk-au mailing list
Talk-au@openstreetmap.org
https://lists.openstreetmap.org/listinfo/talk-au
_______________________________________________
Talk-au mailing list
Talk-au@openstreetmap.org
https://lists.openstreetmap.org/listinfo/talk-au
_______________________________________________
Talk-au mailing list
Talk-au@openstreetmap.org
https://lists.openstreetmap.org/listinfo/talk-au