Bug report #6876
Performance during digitizing in a shape-layer if other big layers in project are snap-able
|Affected QGIS version:||1.8.0||Regression?:||No|
|Operating System:||Windows XP Prof||Easy fix?:||No|
|Pull Request or Patch supplied:||No||Resolution:||no timely feedback|
|Crashes QGIS or corrupts data:||No||Copied to github as #:||16005|
Layer with many elements reduce performance during digitizing in the project significantly if the layers snap is on. This applies to all of the tested file formats or databases (Shape, XML, KML, SpatiaLite, PostgreSQL ...) If these layers, however, saved as MapInfo Tab layer, the performance increases drastically. For example, i generate a vector grid with 170,000 polygons and stored it as well as ESRI-shape and as MapInfo-tab. Both layers are in the actual project. After that i create a new polygon-shape layer in the same project. Then i turn "snap on" on the big TAB-Layer and create an object in new shape layer (It doesn't matter, if it is created "normal" or with the plugin "new memory layer" or if it is an existing Shapelayer). The performance difference between snap on the TAB-layer (high speed) and snap on the SHP-layer (very, very slow) during digitizing is extreme.