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I have a source point table in SRID:4326, and to make it look geographically accurate, I project my project file to SRID:2877 (State Plane CO) (layer still reports source CRS of SRID:4326).

In order to use the Prolong Line feature in Easy Custom Labeling, the project and layer CRS's must match.

But when I set the point layer CRS to SRID:2877 (overriding SRID:4326) the layer moves way over to the middle of Arizona (should be in Denver).

This happens with any of the State Plane CRS's for Colorado Central in the list.

In addition to drawing in the wrong place, it also greatly affects the 'map unit' size I'm using for the symbols and points in my map.

I've tried various datasets from my database and from the City of Denver, with all the same results.

Is there a setting I'm missing to do this accurately?

underdark
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DPSSpatial_BoycottingGISSE
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    It sounds like you are "setting" a coordinate system when you should be "reprojecting" instead. – Mintx Jan 08 '16 at 19:29
  • @Mintx what do you mean? (in relation to the QGIS gui's...) – DPSSpatial_BoycottingGISSE Jan 08 '16 at 20:06
  • Your source data is in lat/longs, but you're changing the coordinate system to Colorado Central. So now lat 39 long -105 becomes X -105 and Y 39 which would put your data around the California/Arizona border. Not too familiar with QGIS but this looks related: http://gis.stackexchange.com/questions/35590/how-to-reproject-a-vector-layer-in-qgis – Mintx Jan 08 '16 at 21:09
  • So does this mean that while a project CRS can be projected on the fly, a layer CRS cannot - and you need to physically re-project a dataset in order to match a projected-on-the-fly CRS ? – DPSSpatial_BoycottingGISSE Jan 08 '16 at 21:11
  • Yes, you need to use Save As ... for vector data and Raster -> Reproject for raster files to get the coordinates into the new CRS. Some features do not look at the OTF settings, so you have to reproject manually. – AndreJ Jan 09 '16 at 06:33
  • @AndreJ you might as well put that as the answer below and I'll mark it as such. – DPSSpatial_BoycottingGISSE Jan 09 '16 at 16:12
  • @mapBaker the question has been closed, so I can't answer anymore. – AndreJ Jan 10 '16 at 06:38
  • @underdark I'd like the answer to reflect the fact that the layer coordinate system settings don't use the OTF settings as AndreJ has pointed out, which is the crux of this question - it's not simply 'how to reproject a vector layer'... thanks! – DPSSpatial_BoycottingGISSE Jan 10 '16 at 15:35
  • @mapBaker I've modified the title so it sounds less like a duplicate. The issue is that most tools use the layer CRS and not the project CRS (even if OTF is enabled). OTF affects ONLY rendering and some measuring tools - but no analysis. – underdark Jan 10 '16 at 19:31
  • @AndreJ Try to add the answer if you can...and note what Anita has provided... – DPSSpatial_BoycottingGISSE Jan 11 '16 at 00:52

1 Answers1

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You may have used Set Layer CRS, which is wrong in most cases and corrupts your data. You better change that back, or get a fresh copy of the data.

You need to use Save As ... for vector data and Raster -> Projections -> Warp(Reproject) for raster files to get the coordinates into the new CRS.

Some features do not look at the OTF settings, so you have to reproject manually. My advice is to turn OTF OFF in such cases and see if the layers still align, before you do operations like analysis, clipping or the Prolong Line feature you want.

AndreJ
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