Re: [Talk-GB] OSM UK's first tile layer

I have submitted a ticket to the JOSM developers. The ticket contains a fully worked-out patch to upgrade the EPSG:27700 projection from the Helmert transformation to the look-up table transformation. I'm afraid this is another somewhat long and technical message. But it does contain an

Re: [Talk-GB] OSM UK's first tile layer

The test will be, if Rob is able to produce example areas processed with the OS look-up table transformation, do the misalignments go away? Sorry for a rather long and technical message. I've done some more investigation and testing. QGIS reckons EPSG:27700 is the OS look-up table

Re: [Talk-GB] OSM UK's first tile layer

I can confirm that the Land Registry wms parcels appear to have been converted with the Helmert 7-element transformation (no look-up table). This gives a misalignment of up to 5 metres. It's ironic that the Land Registry don't seem to know where their parcels are to better than 5m. Now we

Re: [Talk-GB] OSM UK's first tile layer

The Ordnance Survey provides a transformation between OSGB36 and ETRS. It is described on this page https://www.ordnancesurvey.co.uk/gps/transformation/ and on the pages linked from there. The transformation is definitive. In other words, OSGB36 is redefined as being what you get when you apply

Re: [Talk-GB] Finally a RTK / NTRIP Broadcaster in London

@ Grant Slater Thank you for spotting this and making it known. One thing you need to know when using an RTK base station, is what is the reference (datum). Unfortunately there is no convention for how this information is given, and it is often not given at all. The stations listed by Grant