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A map of the Saxo-Bohemian Cretaceous Basin - created with QGIS

tags: qgis, map, saxony, czech republic, poland, bscb
A map of the Saxo-Bohemian Cretaceous Basin extending within the Czech Republic, Germany and Poland. 1:150.000
A map of the Saxo-Bohemian Cretaceous Basin extending within the Czech Republic, Germany and Poland. 1:150.000
Traditionally, the Saxonian and Bohemian Cretaceous Basins (SCB and BCB) are subject to a more or less "separated" research especially due to language and political barriers. A lot of the recently published literature about the SCB and BCB is written in english and now much more easy to use for most of the researches. Especially due to administrative aspects e.g. obtaining proper data differs for the political areas and in some cases is quite difficult. On some very basic level: Getting a proper, simplified (geological) map of all the Cretaceous sediments was quite a problem (for me). What I wanted was one map of the de facto ONE basin - Bohemo-Saxonian or Saxo-Bohemian Cretaceous Basin. I compiled a map with QGIS and freely accessible data of the BSCB (or SBCB) which extends over Germany, Poland and most of it over the Czech Republic .

Update 11/29/2020: The „Geologische Übersichtskarte GÜK400“ of Saxony available at the ArcGIS Feature Service is the „Oberflächenkarte“ version (surface map), where Cenozoic sediments (Paleogene-Recent) are shown. Thus, I used this version of the GÜK400 (without Cenozoic sediments). Read more about the three different versions of the GÜK400 of Saxony (in German).

There does exist compiled maps of the SCB-BCB which extends over the Czech Republic, Saxony and Poland. For example in Greguš et al. 2013 there is a picture of Cretaceous Basins in Europe - containing the BSCB, the North-Sudetic Basin, Intra-Sudetic Basin/Nysa Through. One disadvantage of using such a pre-compiled image of a map occur when doing modifcations like adding own labels or other own data. Hence, I created a map of a similar style within QGIS. It's georeferenced and pretty detailed about the actual extends of (known) occurences of Cretaceous sediments. It is not a paleogeographic map, but a map showing exisiting Cretaceous sediments more or less near the surface. This map is based on data of the Geological Surveys of Saxony, Czech Republic and Poland. All three geological surveys offer a so-called ArcGIS REST Service. These can be accessed within QGIS quite easily. Because the finished map had to be re-used in a GIS, I searched for data available in vector formats, not Raster-Images. Considering the overview approach of such a map, geological data of larger scales seemed to be sufficient. I used geological data provided in a scale between 1:400.000 and 1:500.000 (GK400 and GK500). The following REST-Services were added in QGIS as „ArcGIS-Feature-Service“ and used:

with the layer /geologie/geologie/MapServer/1 (GÜK400 - 1:400.000) by the LfULG Sachsen

with the layer /Geologie/geologicka_mapa500_en/MapServer/6 (GK500 - 1:500.000) by the Česká geologická služba (CGS)

with the layer /kartografia/mgp500k/MapServer/0 (GK500 - 1:500.000) by the Państwowy Instytut Geologiczny/Państwowa służba geologiczna (PGI/PSG)

This three URLs needs to be added as an ArcGIS-Feature-Service within QGIS. In contrary to a Web-Feature-Service (WFS) the perfomance of the REST-Service is much better. Using them within the webbrowser might not work (at the moment the service by the PGI is disabled for webbrowsers).

Due to different national standards concering the CRS/SRS (projections/spatial reference systems) I decided to convert the data into the WGS84 projection (EPSG:3857) which is commonly used e.g. within the Google Maps and OpenStreetMap projects. The de facto "standard" for Saxony is EPSG:25833 (ETRS89 UTM 33N), for Czech Republic it seems to be EPSG:102067 (5514) and for the polish data it is EPSG:2180 (ETRS89). The reprojection of the data was done with QGIS if necessary. A missing WKT/proj4-definition needed for the reprojection can bee obtained by the linked datasets with the proper EPSG-codes. When added and used as a custom CRS (Settings→Custom Projections) a reprojection with a sufficient level of accuracy can be done.

Subsequently adding the geological maps in a vector format, the datasets then had to be adjusted by modifying the areas which should be joined together. Beacuse of the different databases a custom modification had to be done at the joined areas (See images below). The "holes" within some enclosed areas indicate e.g. the occurence of iintrusive (e.g. paleogene/neogene in the eger-graben) remnants. This areas were not modified.

remove the Cetaceous where it actually is notmodifying the datasets

After adjusting all the data, the three data-layers were processed with the "Vector-Dissolve", "Vector-Merge" and "Shape-Repair" Tools from the QGIS-Toolkit and exported into a geopackage (*.gpkg), *.geojson and a *.png file (plus *.pgw world-file).

SCB-BCB in the Czech Republic, Poland and Germany

The QGIS project, showing the compiled map (BSCB = green) on top of the three used geological maps (colors brightend) provided by the german, czech and polish geological surveys.

The BSCB in the Czech Republic, Poland and Germany

The Bohemian Cretaceous Basin („České křídové pánve“) and the Saxonian Cretaceous Basin („Elbtal-Gruppe “ = s.l. „sächsische Kreide“) within the country-borders of Germany, Czech Republic and Poland (1:200.000). The small area just near the border between North-Bohemia and the very southeast of Saxony - the „Zittauer Sandsteingebirge“ - is genetically part of the BCB.

Download the data/map showing the BSCB in BRD-CZ-PL (WGS84 - EPSG:3857):

  • GEOJSON (use for GIS)
  • KML (use for GIS)
  • GEOPACKAGE (sth. like shape-files - use for GIS)
  • PNG (400dpi) - can be used within a GIS with this world-file: PGW
  • SVG

Update: For Poland a version of the 1:1.000.000 map without cenozoic sediments can be found in the layer /kartografia/mgpbk1000k/3. The image below shows the 1:1M map without cenozoic, filtered for „Cretaceous“ (green colors) polygons.

poland geological map without cenozoic 1:1000.000 in QGIS: filtered for Cretaceous only

Update 12/17/2020: Now, a more extensive version with all the Cretaceous Basins/remnants around the Bohemian Massif is available, too.

Compiled map of Cretaceous Basins around the Bohemian Massif


Map-Data, based on the following sources:

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