Changeset: 48546507
Update of Google Dublin buildings using new DigitalGlobe imagery. addition of the Google bridge between their 3 buildings.
Closed by dónal
Tags
created_by | iD 2.2.0 |
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host | https://www.openstreetmap.org/edit |
imagery_used | Bing aerial imagery;DigitalGlobe Standard Imagery |
locale | en-GB |
Discussion
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Comment from Conormap
The updated nodes of this building, while using better satellite imagery, are far less accurate than the previous changeset. They fail to take into account the perspective warping and, instead, trace just the flattened outline of the combined roofs as presented. See how far they are from the building's footprint, for example.
The previous nodes were carefully considered and calculated before drawing, taking into account any perspective warping. I would highly recommend a revert to the previous changeset. -
Comment from dónal
ACK. I'll revert the change later today... :)
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Comment from Conormap
Appreciated, cheers.
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Comment from dónal
revert completed in changeset 49771510. would be interested in learning how to correctly map these types of buildings (the Google Docks building is complex due to it be built out over the pavement as well as being 13/14 stories high). Will bring it up on talk-ie@openstreetmap.org. :)
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Comment from SK53
There is some useful advice on the wiki about how to sort out parallax/perspective issues with imagery: https://wiki.openstreetmap.org/wiki/Roof_modelling.
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Comment from Conormap
There's some good advice there, thanks SK53. You get familiar with common visual deceptions with practice. One thing I'd add is that it helps to recognise that a building will likely have predictable shape patterns, such as 90 degree corners rather than 86 degree corners, etc. and matching parallel edges, whether from the same or a neighbouring building (if they already look pretty close). Take a look at the buildings up in the neighbouring Grand Canal Square to see how lots of lines are parallel.
Ways (8)
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