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I map red squirrel distribution in Clocaenog for Clocaenog Red Squirrels Trust with QGIS. I noticed that the OSM base map only shows 25 Turbines within the Boundary as does the generator overlay. Whereas there are actually 27 in total. Also some are over 130m misplaced. I have made a correct overlay. What is the procedure for correcting anomalys?

asked 20 Nov '20, 09:52

Vic's gravatar image

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Thank you for all suggestions. Access is not a problem in this case so I will GPS the ones that are inaccurate next time I am in the Forest. The email said "Don't forget to come over and cast your vote." Where/how please?

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answered 23 Nov '20, 18:39

Vic's gravatar image

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It is difficult to map them if access is restricted or aerial is unavailable. As SK53 suggested approximate positioning is still helpful, especially for rough navigation. This is a method i used a while ago.

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answered 23 Nov '20, 18:15

andy%20mackey's gravatar image

andy mackey
accept rate: 4%

Best practice is to ask the original mapper via a Changeset Discussion,as this will likely reveal what sources they used & how reliable the data might be.

Alternatively you can add notes on the OSM website for the missing & incorrectly located turbines, or you can edit & adjust them yourself (as long as you dont use copyright Ordance Survey data, and in particular anything related to MasterMap)

Jex Nicholson seems to have done much of the mapping (e.g.,, but although the changeset says Bing Imagery used he may have used other less detailed sources as only some turbines are visible on any current imagery in the OSM editors (ESRI & Maxar Standard. A lot of renewable energy data is entered fairly roughly at first (often because detailed imagery is not available), so we're always open to improving it. As a first cut I have added one turbine & slightly adjusted the position of others, but I dont see any which are 130 m out.

I'm presuming you are encountering these in the field, but one remote possibility if this is GIS-based is use of a suboptimal transform between WGS84 and OSGB National Grid.

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answered 20 Nov '20, 12:56

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SK53 ♦
accept rate: 22%

Thank you for comprehensive reply SK53. I first noticed the difference using Esri World Imagery as my base map. This showed 2 (OSM) unmarked turbines. I checked with an RWE person who confirmed that there are 27 not 25 turbines in Clocaenog. I did move the one which QGIS reckoned was 130 m out and requested a check. I could always check them with a GPS but can't see how to locate by coordinate online.

(20 Nov '20, 13:37) Vic
  1. Log into OpenStreetMap
  2. Zoom to the area in question
  3. Click "Edit"
  4. Follow the tutorial
  5. Make your edits
  6. Save
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answered 20 Nov '20, 12:31

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Richard ♦
accept rate: 18%

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question asked: 20 Nov '20, 09:52

question was seen: 1,028 times

last updated: 23 Nov '20, 18:50

NOTICE: is no longer in use from 1st March 2024. Please use the OpenStreetMap Community Forum