This is probably why dbh is used as the diameter only changes a tiny fraction of the circumferance per year, so the data is less stale and you dont have to audit them every year
On Jun 28, 2017 9:21 PM, "Max Erickson" <[email protected]> wrote: > > > On Jun 28, 2017 6:46 PM, "Kyle Nuttall" <[email protected]> wrote: > > The biggest issue to resolve is tagging the thickness of the trees. The > data was provided as the diameter measured in centimeters. I understand > that the circumference tag was made for ease of use, but anyone that is > collecting data specifically for trees would know the concept of Diameter > at Breast Height. It's my belief that the more the data is manipulated, the > more errors that are introduced. If converting a DBH of 9cm to > circumference in meters, you get 0.2827433388230814...m. How many digits > is sufficient for accuracy? I suppose 0.001m would as much as needed. > > > A sensible conversion shouldn't imply such a precise result. Round > instead. Not quite following the rules for significant figures, a 9 cm dbh > becomes a 0.28 m circumference ( which round trips back to 9 cm using the > same vaguely sloppy method). > > On the other hand, given the morphology of trees and wide use of dbh in > biology, I think it makes sense to use it. In taginfo, centimeter seems to > be the more used unit. Explicit units in the value, like dbh=9 cm makes > more sense to me than putting the unit in the tag (which invites nonsense > like divergent values). > > Overall, I sort of question the value of putting the stem size in osm. > Mostly because the data is fairly likely to go stale as the trees grow (so > anyone who really cares for it is best off going to the source). > > Max > > _______________________________________________ > Imports mailing list > [email protected] > https://lists.openstreetmap.org/listinfo/imports > >
_______________________________________________ Talk-ca mailing list [email protected] https://lists.openstreetmap.org/listinfo/talk-ca
