Thanks for the clarification Ian.
Keep up the great work.
On 22/06/2021 7:27 pm, Little Maps wrote:
Hi Warren, thanks for your feedback. You sent me back to my computer
to re-check some numbers. Remember that the 57,828 kms in the blog
post only includes OSM highway tags from highway=motorway to
highway=tertiary. Other road types, including highway=unclassified,
track, residential etc, are not included in the totals. I just ran
some Overpass Turbo queries to calculate the total length of other
road classes in WA, and this what you get:
OSM ROAD CLASS
DISTANCE (km)
CUMULATIVE TOTALS
Motorway to tertiary
57,828 (as in blog)
57,828
Unclassified
87,195
145,023
Track
77,339
222,362
If you add motorways to tertiary plus unclassified roads in OSM you
get 145,023 kms. This is very close to the total length of roads that
is not managed by DPAW, as you quoted from the WA Main Roads report:
147,676 km. In fact the difference is only 1.8%.
In addition to this, there are 77,339 kms of highway=track in WA in
OSM. This vastly exceeds the length of DPAW managed roads (National
Parks, Forestry) that you quoted from the WA Main Roads report (38,333
km). (I assume that at least some of these "extra" tracks must be on
private property?) It's difficult to compare the numbers any more
closely than this, as Main Roads WA and OSM categorise roads in
different ways.
Thus, the total length of highway=motorway + trunk + primary +
secondary + tertiary + track in WA in OSM = 222,362 km. The total
length of roads that are and are not managed by DPAW that you quoted
from the WA Main Roads report is 186,009 km. So I reckon OpenStreetMap
is doing pretty well really, /especially /on unsealed roads. (Plus,
about 20,000 kms of residential roads have also been mapped in WA, as
well as other road types).
Having said all that, I'm sure that extra roads will be added to OSM
in WA and the NT, as you suggest. Northern Qld is probably in the same
boat. However, the total length of these roads will be very minor
compared to what's already been mapped.
Anyhow, thanks for keeping me honest, I'm glad I didn't stuff the
numbers up that badly! Best wishes Ian :)
On Tue, Jun 22, 2021 at 6:54 PM Warren via Talk-au
<[email protected] <mailto:[email protected]>> wrote:
An impressive effort Ian but I think you have underestimated the
length
of Roads in WA.
From Main Roads WA report:
Road length excluding DPAW managed roads = 147,676
DPAW managed Roads (National Parks, Forestry etc) = 38,333
Mappers in WA have a long way to go. I suspect a large percentage of
the sealed roads have been mapped on OSM. The remainder are
almost all
unsealed.
The NT may be in a similar position.
Nonetheless an interesting report. Thanks for sharing.
Warren
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