OpenStreetMap
Deteriorating Bing aerial imagery. - Mount Arrowsmith, Vancouver Island, British Columbia, Canada
Posted by Robert Copithorne on 3 March 2017 in English.Referring to the OSM map of part of BLK 1324S on Mt Arrowsmith / Mt Cokely at the location
osm.org/?mlat=49.2676&mlon=-124.5756#map=16/49.2676/-124.5756:
Previous versions of Bing aerial imagery available through Java OSM editor clearly showed a harvested area and related roads surrounding the reference point, which were mapped and tagged as farmland. Tree farm that is, a concept with legal meaning in British Columbia.
Current available versions do not show the harvested area, indicating a change in the aerial photos, possibly to an earlier date.
Mapbox satellite views of the same area clearly show the harvested area.
What has happened? Why the change in Bing Satellite imagery? An explanation is desired, and a revision to Bing aerial imagery if necessary.
Discussion
Comment from Alan Trick on 3 March 2017 at 17:31
You can check out the supposed current date of that area using the Bing imagery analyzer for OSM by Martijn van Exel link to area. That indicates the current ones where taken between December 2009 and September 2016, I think. 7 years is a hell of an approximation, so I may be reading that wrong. Also, I don’t think it’s possible to find the date of the old imagery.
I also recall a diary entry a bit ago indicating that bing was apparently updating its imagery in some places, but it seems strange that it would update it with older imagery.
Comment from Alan Trick on 3 March 2017 at 17:40
I looked into it using the Bing API directly and it looks like there actually is a 7 year approximation for the image capture date.
Comment from SimonPoole on 3 March 2017 at 22:41
Why don’t you simply use the mapbox imagery it it is more recent?
While I can understand the moaning a bit,, microsoft did not, and has not entered in to an agreement with “OSM” to provide the latest up-to-data imagery or matter of fact has entered in to any obligation to provide anything. Or put differently: if you are not happy, you should simply go and organize something better.
Comment from BushmanK on 4 March 2017 at 01:40
For keeping wooded vegetation up to date, I’d recommend using either Landsat 8 or Sentinel 2 imagery - both sources have worse resolution than WorldView (Bing/Mapbox), but usually, more recent images are available.
And regarding of this particular area - this is an extreme example of tagging for the renderer. I’m referring to:
https://wiki.openstreetmap.org/wiki/Tag:landuse=farmlandintended for agricultural farms, not tree “farms”, unlikehttps://wiki.openstreetmap.org/wiki/Tag:landuse=plant_nursery(if it’s a case here) orhttps://wiki.openstreetmap.org/wiki/Tag:landuse=logging;https://wiki.openstreetmap.org/wiki/Tag:boundary=administrativelike here way/459711605 ;name=like here way/433058496 .Sure, nobody can make you follow the rules, but why don’t you do that by yourself? I have provided some links that might help with that.
@SimonPoole, while I totally support your argument about Microsoft having no obligation to provide anything to us, it is a kind of odd to read your “different wording” in the last sentence. This is an example of fallacious reasoning, to be precise - an appeal to accomplishment. I don’t know, why you’ve used this kind of argument.
Comment from Warin61 on 5 March 2017 at 06:41
@BushmanK ? landuse=logging ! Really! That is another ‘bad tag’. It describes an activity .. not a use.
Where wooded vegetation is ‘harvested’ for produce .. for live tress suitable for transplanting then landuse=plant_nursery is suitable for dead trees (wood produce), or foliage for oil, or sap then the landuse=forest is suitable.
The landuse does not have to constantly be updated with the planting, growth, harvest and fallow cycles .. that is implicit in that use. In the same way a farm field is not constantly updated with the planting, growth, harvest and fallow cycles.
Comment from Warin61 on 5 March 2017 at 06:44
Sorry that did not format well
Where wooded vegetation is ‘harvested’ for produce ..
for live tress suitable for transplanting then landuse=plant_nursery is suitable
for dead trees (wood produce), or foliage for oil, or sap then the landuse=forest is suitable.
The landuse does not have to constantly be updated with the planting, growth, harvest and fallow cycles .. that is implicit in that use. In the same way a farm field is not constantly updated with the planting, growth, harvest and fallow cycles.
Comment from BushmanK on 5 March 2017 at 15:51
@Warin61, any area where trees were just cut, can easily be identified. If it was somehow recultivated later, it should be re-tagged then. So, I don’t really see an issue here - it is a verifiable condition of an area. This tag might be a bit rough, however, it doesn’t mean it is not verifiable.
While what you’ve proposed is extremely broad, so it makes this kind of tagging practically unusable - it is impossible to find out, what exactly is there at present moment: young planted trees, stumps or whatever.
Comment from Warin61 on 5 March 2017 at 21:54
I am not proposing anything, but I am saying that landuse=logging is very poor. If the condition ‘logging’ needs to be tagged then don’t use landuse, as it is not a use .. but an activity .. like sport?
LandUSE=residential, commercial, industrial, farmland, forest(ry) … all uses landCOVER=wood,grass etc
As I said, logging is an activity. Does not fit in the present OSM tagging structure .. if it needs to be tagged than we need a tagging method for it… I have nothing as yet .. dictionary .. for activity to se if I can get an idea … no .. nothing there.
As far as what is verifiable .. yes .. but the logging itself is short term .. like a car parked, we don’t map that, so why map logging?
. The before/after logging is landcover… possibly using height to signify the relative sizes? Further complications … I think you are using ‘logging’ for clear felling .. where all the tress are removed. There is also ‘selective logging’ where only some trees are removed.
Comment from Alan Trick on 5 March 2017 at 22:15
What’s the difference between forestry & logging?
Comment from Robert Copithorne on 7 March 2017 at 19:10
What’s the difference between forestry & logging? The following addresses this question, and then discusses the issues raised by trying to map forests subject to both processes.
With apologies to Alan Trick; part of this comment has appeared in my reply to a recent email received from you.
Many people think of the two as the same but logging is the removal of a stand of trees for some purpose, such as land clearing or logging. Logging is one step in the process of continuous forest management.
Forestry or forest management begins with the assessing of a stand, and preparing a management plan. Usually, if the stand is suitable, it can be harvested, regenerated and grown to a mature state, ready for the process to begin again.
The similarities with farming of single or multi year crops are such that I have no problem with referring to managed forest land as farmland, regardless of its stage in the growth cycle.
The key distinguishing feature of forest farming is a management plan covering one or more rotation cycles.
Forest farmland generally exists in two states:
Recently harvested areas, either regenerated or to be regenerated by natural regeneration or planting. At this stage of the rotation cycle, my choice of tags is: landuse=farmland. Such areas are easily distinguishable from aerial photos, and on the ground. While walking on trails in managed forest areas, one is aware mainly of the changes from recently harvested to unharvested areas.
Unharvested areas. These are either mature and available for harvest, or still growing. the defining point at which they become available for harvest depends on the balance of current growth to the growth that would be achieved in a new stand, after harvesting and regeneration and is a key decision in the overall management plan. These areas are much more difficult to determine from aerial photos, or on the ground, and I prefer to use the tag natural=wood. Although they not identical to old-growth forests, as second growth approaches maturity, at least in stands in Temperate rain forests, they have enough similarities that for mapping purposes they can be tagged with a natural tag.
It should be noted that there are virtually no unmanaged forest stands in the area of Temperate rain forest, where I am carrying out my mapping.
I’m aware that there has been some past discussion of the basic tags to be used on wooded areas, but none seem to provide a satisfactory solution to the separation of the two states.
This explains in part why I am distressed when as source of information that I have been used to map the landuse of forested areas, such as has occurred with the change in the available Bing aerial imagery. The Mapbox satellite photos that are now available have significant deficiencies in this area which is very mountainous, ii.e. clouds which obscure the harvested areas and the roads constructed to extract the resources produced by harvesting.