Prerequisites

Get the historical OSM data of the project do following the README instructions.

Data loading in QGIS

• Open a new QGIS project
• [OPTIONNAL] Open an OSM map with QuickMapServices to compare it with the data and have the OSM projection
• Search the directory of the software in the project and go to the project data directory. You will have something like this

• Double click on the perimeter file (KEN_Kakuma-2-3_perimeter.json in this example)
• Right click on the layer to zoom on it
• Double click on the other files. If there are several geometry you can choose Select All to create a layer by geometry

You have an ugly map with bad symbology and all version of OSM objects displayed

Data filtering

You have already done the map of the project at the end with current OSM data with this tutorial.

You want for example to the same map with the situation at the beginning of the project. As you have noticed the date of the beginning of the project is written in the data file name (28th May 2019 in our example). You can filter on the expression

"@validFrom" = '2019-05-28T00:00:00.000'

and create on new layer with this selection to apply later predefined symbology. In our example, we keep only 9 amenity polygons.

If you want a map at the middle of the project, for example the elements at the 1st July 2019. You can filter on the expression

"@validFrom" < '2019-07-01T00:00:00.000' and "@validTo" >= '2019-07-01T00:00:00.000'

In our example, we keep only 11 amenity polygons as we can see in the following image.