1.. _vector.nas: 2 3NAS - ALKIS 4=========== 5 6.. shortname:: NAS 7 8.. build_dependencies:: Xerces 9 10The NAS driver reads the NAS/ALKIS format used for cadastral data in 11Germany. The format is a GML profile with fairly complex GML3 objects 12not easily read with the general OGR GML driver. 13 14This driver depends on GDAL/OGR being built with the Xerces XML parsing 15library. 16 17The driver looks for "opengis.net/gml" and one of the strings semicolon 18separated strings listed in the option **NAS_INDICATOR** (which defaults 19to "NAS-Operationen;AAA-Fachschema;aaa.xsd;aaa-suite") to determine if a 20input is a NAS file and ignores all files without any matches. 21 22In GDAL 2.3 a bunch of workarounds were removed, that caused the driver 23to remap or ignore some elements and attributes internally to avoid 24attribute conflicts (e.g. *zeigtAufExternes*). Instead it now takes the 25**NAS_GFS_TEMPLATE** option, that makes it possible to cleanly map 26element paths to feature attributes using a GFS file like in the GML 27driver. Multiple geometries per layer are also possible (eg. 28ax_flurstueck.objektkoordinaten next to the regular wkb_geometry). 29 30A `GFS 31template <https://github.com/norBIT/alkisimport/blob/master/alkis-schema.gfs>`__ 32and a corresponding `PostgreSQL 33schema <https://github.com/norBIT/alkisimport/blob/master/alkis-schema.sql>`__ 34of the full NAS schema are part of `norGIS 35ALKIS-Import <http://www.norbit.de/68/>`__ (also featuring a shell 36script and PyQt frontend which ease the import). The two files were 37generated using `xmi2db <https://github.com/norBIT/xmi2db/>`__ (fork of 38`xmi2db <https://github.com/pkorduan/xmi2db>`__) from the official 39application schema. 40 41New in 2.3 is also the option **NAS_NO_RELATION_LAYER** that allows 42disabling populating the table *alkis_beziehungen*. The information found 43there is redundant to the relation fields also contained in original 44elements/tables. Enabling the option also makes progress reporting 45available. 46 47This driver was implemented within the context of the `PostNAS 48project <http://trac.wheregroup.com/PostNAS>`__, which has more 49information on its use and other related projects. 50 51Driver capabilities 52------------------- 53 54.. supports_georeferencing:: 55 56.. supports_virtualio:: 57