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Official geodata for site plans: ALKIS, basemap.de, aerial photos
Which official data exists in Germany, who maintains it, what it contains and where it stops.
The names stand for data sources and services TerraSight uses. All rights remain with their owners, and the providers are not affiliated with TerraSight. Licences and attributions: data sources.
Anyone starting a site plan needs parcels, buildings, streets and a current picture of what exists. In Germany this data is officially recorded but spread across several systems and 16 federal states. This overview shows what exists, who provides it and where the data stops.
| Data | Source | Contains | Used in the site plan for |
|---|---|---|---|
| ALKIS | State surveying authorities | Parcels, building footprints, addresses, actual land use | Boundaries, parcel numbers, areas, land use |
| basemap.de | Federal and state governments, distributed by the BKG | Topographic map: buildings, transport, water, vegetation, labels | Buildings and surroundings |
| Digital orthophotos (DOP) | State surveying authorities | Rectified aerial photos, usually 20 cm ground resolution | Checking existing features, detecting trees |
| Municipal data | Cities | Depending on the city: carriageways and pavements as surfaces, tree registers | More accurate street spaces and city trees |
ALKIS: the property cadastre
ALKIS stands for Amtliches Liegenschaftskataster-Informationssystem, the official property cadastre information system. The working committee of the state surveying authorities (AdV) designed the model uniformly for the whole country, but each state runs the cadastre for its own territory. It holds parcels with boundaries, numbers and areas, building footprints, addresses and actual land use.
Since 9 June 2024, parcels count as high-value datasets under EU Implementing Regulation 2023/138, which should in principle be free of charge, machine-readable and available through APIs. Implementation varies, however, and licence and scope depend on the state. TerraSight currently connects to the ALKIS services of 15 states. For Bavaria, no open vector service is currently available to us.
Important for planning: a parcel boundary from the service is a depiction for orientation and does not replace a survey. Our article What must a site plan contain? explains when a building application needs certified documents.
basemap.de: the official map
basemap.de is a joint map by the federal and state governments, developed within the AdV. Its main source is the base landscape model from the ATKIS topographic information system, supplied by the states. It is available as vector and raster services and as open data. According to the BKG terms of use, basemap.de is licensed under CC BY 4.0, so attribution is mandatory.
In a site plan it provides buildings, roads and surroundings. It is a map rather than the cadastre: ALKIS remains the source for boundaries and official areas.
Orthophotos: the official aerial photo
Digital orthophotos are rectified aerial photos derived from survey flights and a terrain or surface model. The states usually provide them at 20 cm ground resolution, sometimes finer, and often as a free WMS service. The flight cycle differs by state: Schleswig-Holstein, for example, states a two-year cycle. So always check the capture date.
Orthophotos show what maps leave out: the actual trees, surfaces and minor structures. Edges of tall buildings can appear shifted in the image, so they work better for checking against vector data than as the only thing to trace from.
Municipal data: street spaces and city trees
Some cities publish more detailed data than the states hold. Berlin, Hamburg, Aachen and Rostock provide street space data as surfaces, which TerraSight uses directly. Many other cities publish only centre lines; there, TerraSight generates the street cross-section itself. We currently use tree registers for Berlin and Potsdam.
What official data leaves out
Even used in full, this data does not make a finished plan. Tree registers usually cover street and park trees but not trees on private land. Street furniture, surfaces and newly completed buildings are often missing or arrive late. Traditionally these gaps get traced from the aerial photo.
This is where the Tree AI in TerraSight comes in: it detects trees in the aerial photo and proposes them in the editor. The model runs locally in your browser, and you can review the proposals before they stay in the plan.
Licences and attribution
Open geodata does not come without conditions. The usual licences are the Data Licence Germany in its Zero and Attribution variants and CC BY 4.0, and many of them require attribution. TerraSight adds it on export. The exact licences and credits for each state and city are on our data sources page.
Outside Germany
In Austria and Switzerland, TerraSight uses geodata from BEV and geo.admin.ch where connected, supplemented by OpenStreetMap data. Outside Germany, and when a state service is down, TerraSight shows Esri World Imagery as the aerial photo.
Sources
- Implementing Regulation (EU) 2023/138 on high-value datasets
- basemap.de terms of use (BKG) (in German)
- Documentation on digital orthophotos (BKG) (in German)
- ALKIS brochure by LVermGeo Saxony-Anhalt (in German)
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