Hi Brent, Try switching off simplification in the "layer properties" - "rendering" tab. Does that help?
Nyall On 08/08/2014 11:42 am, "Brent Wood" <pcr...@pcreso.com> wrote: > > Hi, > > Apologies for an attachment to a list email, but I kept it small... > > The attached image shows some Antarctic data (grounding line & ice shelf extent) with a polygon overlayed. > I created the polygon by editing a text (csv) file with lat/longs: > x,y > 150,-60 > 150,-85 > 255,-85 > 255,-60 > > I opened it in QGIS (CRS=EPSG:4326) & created a new polygon shapefile layer (snapping to the points) to create a box defined by the same points. > > Then I opened the Antacrctic layers (WFS from NSIDC http://nsidc.org/cgi-bin/atlas_south in EPSG:3031 - Antarctic Polar Stereographic) > > I set the QGIS project CRS to a user defined one, same as EPSG:3031, but with +lon_0=180 instead of 0 which gives a 180 up map instead of 0 up. > > The map is displayed as in the attached image - a strange box is drawn to the north of the box polygon, the eastern points & vertices do not appear - and if the layer is editable, they cannot be clicked on as nodes. > > If I swap the CRS to EPSG:3031, the inverted map renders the box better (no extra box outside it) but the points are still rendered in a different location to the polygon vertices - but they share the same coordinates. > > I can usually work around 180 issues in QGIS by using longitudes in the 0-360 space, but it seems to me that there are some issues with QGIS working in a polar projection across 180. > > Does anyone know if there is a way to solve this, or is this an inherent problem for now? In the short term I need to decide whether or not I can progress with QGIS in the cross 180 polar space, or will need to find another tool. > > In the longer term, if this is an issue, I'd like to work with a developer to resolve it - and may be able to fund (some of?) the work required. > > > Thanks, > > Brent Wood > > > _______________________________________________ > Qgis-user mailing list > Qgis-user@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/qgis-user
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