Bug report #6472

Qgis 1.8.0 converts WGS84 to OSGB36 incorrectly

Added by Ian Goddard about 10 years ago. Updated over 8 years ago.

Affected QGIS version:master Regression?:No
Operating System: Easy fix?:No
Pull Request or Patch supplied:No Resolution:
Crashes QGIS or corrupts data:No Copied to github as #:15703


In attempting to georeference old OS maps I noticed that converting lat/long to OS grid gives different results to coordinates provided by OS, e.g. on Streetmap.co.uk. Coordinates from Google maps via OpenLayers with on-the-fly reprojection give similar incorrect results. To replicate Settings>Custom CRS. In Test section give parameters +proj=tmerc +lat_0=49 +lon_0=-2 +k=0.9996012717 +x_0=400000 +y_0=-100000 +ellps=airy +datum=OSGB36 +units=m +no_defs and 53.5502777778, 1.8008333333 and calculate result. In 1.7.0 & 1.4.0 the results are 413293 405979 which compares with Streetmap's coordinates for the same point. On 1.8.0 the result is 413194, 406006

To find the location on www.streetmap.co.uk search for Cartworth. The location is the junction of Cartworth Moor Rd & Weather Hill Lane.

Platform is Debian Squeeze AMD 64


#1 Updated by Ian Goddard about 10 years ago

After some more checking, 1.8.0 is OK on windows & master is OK on Squeeze. Maybe it's a problem with one or two specific builds.

#2 Updated by Jürgen Fischer over 8 years ago

  • Status changed from Open to Closed

probably fixed.

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