Yes, seems restricted to reprojection cases This seems to be an issue with the spatial filter issued to OGR
At the zooms where the lines disappear, there are requests like: Thread 23 "Thread (pooled)" hit Breakpoint 2, OGR_L_SetSpatialFilterRect (hLayer=0x7f81180c90a0, dfMinX=-179.79163612932865, dfMinY=-69.446164378986353, dfMaxX=179.90530755284408, dfMaxY=78.959077253477474) at ogrlayer.cpp:1223 At the zooms where that work (even when zoomed in), there are like: Thread 29 "Thread (pooled)" hit Breakpoint 2, OGR_L_SetSpatialFilterRect (hLayer=0x7f81180c90a0, dfMinX=-180, dfMinY=-90, dfMaxX=180, dfMaxY=90) at ogrlayer.cpp:1223 I haven't looked at the QGIS code that computes this bounding box, but from my experience with gdalwarp which has similar challenges, it is tricky to compute a source bounding box from a target bounding box, because sometimes the coordinates in the target bounding box do not correspond to a physical point on Eath, and hence inverse projection fails. So you have to resort to a grid sampling approach, but that makes you miss the exact boundaries. So probably that a band-aid fix would be to add some ad-hoc logic, like "if the source SRS is long/lat, and the computed extent is almost worldwide, then extend it to full worlwide (or do not emit a spatial filter at all)" Even > With EPSG:4326 it does not seem to happen, but I tried EPSG:3857 and the > -180,180 grid lines do appear and disappear at different zoom levels. I > also confirm this with the Robinson projection with the addition that the > -90, 90 degree latitude lines also appear and disappear. > > Calvin > > On Tue, Aug 28, 2018 at 3:31 PM, Andreas Neumann <a.neum...@carto.net> > > wrote: > > Hi again, > > > > For some time already I noticed that, depending on the zoom level, the > > -180 / 180 degree grid lines appear / disappear in QGIS. This is unrelated > > to the EqualEarth projection just discussed and also appears on other > > world > > projections, like the Robinson projection. > > > > Here is the testfile I used with world (countries) and gridlines: > > http://www.carto.net/neumann/temp/gridlines.gpkg > > > > Can you reproduce this behaviour? > > > > Any idea why this happens and how this could be fixed? > > > > Thanks, > > > > Andreas > > > > > > _______________________________________________ > > QGIS-Developer mailing list > > QGIS-Developer@lists.osgeo.org > > List info: https://lists.osgeo.org/mailman/listinfo/qgis-developer > > Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-developer -- Spatialys - Geospatial professional services http://www.spatialys.com _______________________________________________ QGIS-Developer mailing list QGIS-Developer@lists.osgeo.org List info: https://lists.osgeo.org/mailman/listinfo/qgis-developer Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-developer
