<html> <head> <title>NAS - Normbasierte AustauschSchnittstelle</title> </head> <body bgcolor="#ffffff"> <h1>NAS - ALKIS</h1> <p>The NAS driver reads the NAS/ALKIS format used for cadastral data in Germany. The format is a GML profile with fairly complex GML3 objects not easily read with the general OGR GML driver.</p> <p>This driver depends on GDAL/OGR being built with the Xerces XML parsing library.</p> <p>The driver looks for "opengis.net/gml" and one of the strings semicolon separated strings listed in the option <b>NAS_INDICATOR</b> (which defaults to "NAS-Operationen;AAA-Fachschema;aaa.xsd;aaa-suite") to determine if a input is a NAS file and ignores all files without any matches.</p> <p>In GDAL 2.3 a bunch of workarounds were removed, that caused the driver to remap or ignore some elements and attributes internally to avoid attribute conflicts (e.g. <i>zeigtAufExternes</i>). Instead it now takes the <b>NAS_GFS_TEMPLATE</b> option, that makes it possible to cleanly map element paths to feature attributes using a GFS file like in the GML driver. Multiple geometries per layer are also possible (eg. ax_flurstueck.objektkoordinaten next to the regular wkb_geometry). <p>A <a href="https://github.com/norBIT/alkisimport/blob/master/alkis-schema.gfs">GFS template</a> and a corresponding <a href="https://github.com/norBIT/alkisimport/blob/master/alkis-schema.sql">PostgreSQL schema</a> of the full NAS schema are part of <a href="http://www.norbit.de/68/">norGIS ALKIS-Import</a> (also featuring a shell script and PyQt frontend which ease the import). The two files were generated using <a href="https://github.com/norBIT/xmi2db/">xmi2db</a> (fork of <a href="https://github.com/pkorduan/xmi2db">xmi2db</a>) from the official application schema.</p> <p>New in 2.3 is also the option <b>NAS_NO_RELATION_LAYER</b> that allows to disable populating the table <i>alkis_beziehungen</i>. The information found there is redundant to the relation fields also contained in original elements/tables. Enabling the option also makes progress reporting available.</p> <p>This driver was implemented within the context of the <a href="http://trac.wheregroup.com/PostNAS">PostNAS project</a>, which has more information on its use and other related projects.</p> </body> </html>