QMapCompare

A QGIS plugin that enables you to compare maps smoothly.

(QGIS version 3.34 and above is required)

© OpenStreetMap Contributors © Geospatial Information Authority of Japan

Usage

• On left bottom panel, select comparing layers and click on one of the following buttons to start comparison:
  • Mirror
  • Vertical split
  • Horizontal split
  • Lens
• Map are updated on the fly when toggling comparing layers.
• Click on Stop button to end comparison.

Notes

• On Split and Lens mode, a masking group layer QMapCompare_Group where comparing layers are duplicated in, is added. Editing this group manually may cause unexpected visualization.
• Lens mode may not work in case of data where rendering takes a while (e.g. high volume of data or layer which needs CRS transformation). It can be solved manually with one or more of the following methods:
  • (1) Set the project CRS to be the same as compare layers to avoid CRS transformation.
    • Setting the project CRS and converting compare layers to EPSG:3857 are highly recommended.
  • (2) Set lens rendering time interval.
    • Go to QMapCompareMask layer properties.
    • Rendering Tab -> Refresh Layer at Interval -> Set an interval time longer than 0.2s.
    • Lens comparison may not be efficient when interval exceeds 1 second in case of very huge and/or complex data.
  • (3) Reduce the volume and/or the complexity of rendering as following examples:
    • Convert CSV SHP etc. to GPKG
    • Filter to hide unused data
    • Simplify or split complex geometries

More information

• English
• Japanese

Authors

• Raymond Lay (@bordoray) - original author
• And all contributors