My colleague just told me about incorrect measure distance tool results in QGIS. For reference we used this pond.
both show about 970 meters distance, QGIS shows me about 1500 meters:
I first though it is OTF reprojection issue so I switched it off. But problem remains. The results are same for various Openlayers map services (OSM, Bing etc.) but also for OSM derived offline data.
I have my data in EPSG:3857 - WGS84 Web Mercator in order to be able to let the beginner users switch between offline and online data without slowing down the map loading and avoiding the need of OTF reprojection.
Is there something wrong with this particular projection? I would not expect such a huge differences for this small area.