ALKIS NAS to GeoPackage Converter
Converts an ALKIS NAS file (.xml) to a GeoPackage with GDAL's NAS driver.
Upload one unzipped ALKIS NAS file (.xml, up to 50 MB). The worker reads it with GDAL's NAS driver, takes the coordinate system from the NAS header and writes every ALKIS object type as a layer into one GeoPackage.
Need the data in a CAD program? Every object type on its own layer: ALKIS NAS to DXF Converter
Drag a file here to convert, or select file
Accepted: .xml · max. 50 MB
What the converter does
- The worker first checks that the file is NAS: GML with AdV/NAS identifiers in the header. Other files are refused with an explanation.
- GDAL reads the file with the NAS driver (-if NAS). Without this option GDAL 3.10 opens NAS files with the generic GML driver.
- The coordinate system comes from the NAS header: urn:adv:crs:ETRS89_UTM32 becomes EPSG:25832, ETRS89_UTM33 becomes EPSG:25833 (set with -a_srs, GDAL does not do this itself). Other codes are not assigned; the report asks you to assign the coordinate system in your GIS.
- Every ALKIS object type becomes a layer, e.g. AX_Flurstueck, AX_Gebaeude or AP_PTO.
- Properties that occur more than once are kept as lists and stored as JSON text, e.g. [ "urn:nw:fdv:8102", "urn:nw:fdv:8103" ].
- GDAL prints "ERROR 1: No schema information loaded" because NAS files come without schema; GDAL then derives the layer structure from the file itself. In all tests every feature was converted.
- The report below the upload shows layers and features read and written, skipped layers with the reason, GDAL's warnings and the exact commands.
GDAL command the worker runs
AX_Flurstueck stands for the object types in your file; the worker lists all of them in one call (e.g. AX_Hafenbecken AP_PTO AP_Darstellung). -a_srs is only added when the header names ETRS89_UTM32 or ETRS89_UTM33.
Tested with
| Test file | Result |
|---|---|
| 40 parcels (AX_Flurstueck) from Herne, 275 KB | 40 of 40 polygons, EPSG:25832 from the header, 26 fields incl. flurstueckskennzeichen and amtlicheFlaeche |
| 40 buildings (AX_Gebaeude) from Herne, 358 KB | 40 of 40 polygons, EPSG:25832 |
| 7 harbour basins (AX_Hafenbecken), 1 label (AP_PTO), 1 AP_Darstellung, 103 KB | 3 layers, 9 of 9 features; AP_Darstellung has no geometry |
| 45 MB extract with the first 5,177 parcels of the Herne parcel file | 5,177 of 5,177 in 2.1 s on a desktop PC (local run, not on the live worker) |
Tested on 24 Sep 2026 with the worker code of this site and GDAL 3.10.3 (conda-forge build on Windows). The worker image runs the Debian build of the same GDAL version; the live worker was not part of these tests. Test data: OpenGeodata.NRW, Grundrissdaten (NAS), package Herne, as of 2026-07-28, licence dl-de/zero-2-0. Only NRW data (GeoInfoDok 7.1) was tested.
Limits
- Upload: one unzipped .xml file up to 50 MB. ZIP archives are not accepted on this route.
- The NRW district packages are larger: the smallest, Herne, is a 91.7 MB ZIP with 62 XML files (3.8 GB unpacked); its parcel file alone is 549 MB. Only single files up to 50 MB fit.
- Only ETRS89/UTM zone 32 and 33 are assigned automatically.
- The layer structure is GDAL's own; the worker uses no GFS template (NAS_GFS_TEMPLATE).
- Each GDAL step may run for up to 240 seconds; a longer run is stopped with an error message.
- Need files over 50 MB? Email us your file size and format.
Frequently Asked Questions
What does GDAL need to read NAS?
The NAS driver, which requires GDAL built with Xerces-C. The worker image uses the Debian package of GDAL 3.10.3, which is built with Xerces-C; the image build stops if the NAS driver is missing.
Why is -if NAS in the command?
In our tests with GDAL 3.10.3 the NRW files were opened by the generic GML driver unless -if NAS was given. With -if NAS the NAS driver reads them.
Which coordinate system does the GeoPackage get?
The one named in the NAS header: ETRS89_UTM32 becomes EPSG:25832, ETRS89_UTM33 becomes EPSG:25833. For other codes the layers get no coordinate system and the report says so.
What happens to my file?
Your browser uploads it directly to the GDAL worker on Fly.io (region Frankfurt). The worker converts it in a temporary folder and deletes the folder after sending the result, or immediately if the conversion fails. Files are not stored permanently.