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On 03/03/2011 03:21, Jason Cunningham wrote:
<blockquote
cite="mid:AANLkTim_52uCjjjRNteR1HPz27ZMFwPwPDLcZVZ2Gw9G@mail.gmail.com"
type="cite">Well done to all those who finished off the road
network in Southwark. I was drawn into OSM when searching for a
mapping solution in the far south of Southwark, and it's brilliant
to see how things have come along.<br>
<br>
Tom, I've noticed you've added a large number of trees with
species details supplied by Southwark Council. Some of the trees
appear a bit random<br>
eg <a moz-do-not-send="true" href="http://osm.org/go/euuuYWULe--">http://osm.org/go/euuuYWULe--</a><br>
Whats the story behind this? I wondering if they're from
Southwarks TPO list? or list of plum trees?<br>
Noticed Southwark are one of the better councils for providing
maps on their website showing important info (hopefully they can
start using OSM as the base map)<br>
<br>
cheers<br>
<br>
Jason<br>
<br>
</blockquote>
Tom posted a picture on Flickr a while ago and I asked him the same
question: <a class="moz-txt-link-freetext" href="http://www.flickr.com/photos/tomchance/5415845316/">http://www.flickr.com/photos/tomchance/5415845316/</a>.<br>
<br>
The best place to get a sense of completeness is <a
href="http://osm.org/go/euuudw2m">Peckham Rye Common & Park</a>:
I confess to having <a
href="http://www.openstreetmap.org/browse/changeset/7439566">corrected</a>
a typo on a couple of the trees.<br>
<br>
I find this an exciting development: a place where I can point to
and put pressure on other councils to make their tree databases
available. My particular interests lie with good specimen trees and
relatively unusual ones which are hosts to particular insects (e.g.,
Gleditsia, Holm Oak).<br>
<br>
I have two minor reservations, which the Southwark data set shows:<br>
<br>
1) Overlaying individual trees on an existing closed way showing
woodland (see Peckham Rye Park). My suspicsion is that although this
is closed canopy it's not really a wood (its nigh on impossible to
keep accurate records of trees in woodland as the Lady Park Wood
experience has shown). Of course this can be handled by
post-processing in the renderer, but I think it needs a little
thought as to how such things are mapped.<br>
<br>
2) Tagging the botanical name. There is little point in pushing
individual trees into OSM without this. There are three (perhaps
more) schemes : name:botanical=*, species=* and taxon=*, each with
various merits and demerits. The former is the most popular (a JOSM
preset I think), but although comprehensible, it does horrible
things to the meaning of the name tag, as name is usually used to
things, not types of things. (I am not named <i>Homo sapiens</i>
under any nomenclature, nor am I going to tag phone boxs name=K5).
Species is fine until we start using it for varieties like <i>Prunus
cerasifolia</i> 'Pissardi' (called by Alan Mitchell, "Pissards
'orrible Plum") and <i>Prunus cerasifolia</i> 'Nigra'. Or for
things like <i>Prunus </i>'Kanzan', which is such a mix of
genetics no-one knows where it came from & therefore it does not
have a specific name. That is why I have preferred taxon, the
generic term which covers any scientific name whether for a species,
a variety, a cultivar, genus or aggregate. I labour this point
because experience tells me that this type of pedantry is important
for maintaining credibility with naturalists: ultimately it is
naturalists and tree enthusiasts who might maintain this data.<br>
<br>
If my local council is anything to go by there will be plenty of
mis-identified trees, or ones which it hasn't been possible to
identify (typically Victorian oddities), plus new planting which has
been badly sourced and thus isn't what it purports to be.<br>
<br>
Thanks again to Tom for seeing this through.<br>
<br>
Jerry<br>
<br>
P.S. just seen Tom's comment about trees obscuring street names too.<br>
<br>
<br>
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