# INTERLIS

OGR has support for INTERLIS reading and writing.
INTERLIS is a standard which has been especially composed in order to fulfil the requirements of modelling and the integration of geodata into contemporary and future geographic information systems. With the usage of unified, documented geodata and the flexible exchange possibilities the following advantage may occur:

- the standardized documentation
- the compatible data exchange
- the comprehensive integration of geodata e.g. from different data owners.
- the quality proofing
- the long term data storage
- the contract-proof security and the availability of the software

OGR supports INTERLIS 1 and INTERLIS 2 (2.2 and 2.3) with the following limitations:

- Curves in Interlis 1 areas are converted to line segments
- Embedded INTERLIS 2 structures are not supported
- Incremental transfer is not supported
- Interlis 1 Surface geometries with non-numeric IDENT field are not included in the attribute layer
- Transfer id (TID) is used as feature id

## Model support

Data is read and written into transfer files which have different formats in INTERLIS 1 (.itf) and INTERLIS 2 (.xtf). Models are passed in IlisMeta format by using "a_filename.xtf,models.imd" as a connection string.

IlisMeta files can be be generated with the ili2c compiler. Command line example:

    java -jar ili2c.jar --ilidirs '%ILI_DIR;http://models.interlis.ch/;%JAR_DIR' -oIMD --out models.imd model1.ili [model2.ili ...]

Some possible transformations using ogr2ogr.

- Interlis 1 -> Shape:

      ogr2ogr -f "ESRI Shapefile" shpdir ili-bsp.itf,Beispiel.imd

- Interlis 2 -> Shape:

      ogr2ogr -f "ESRI Shapefile" shpdir RoadsExdm2ien.xml,RoadsExdm2ien.imd

  or without model:

      ogr2ogr -f "ESRI Shapefile" shpdir RoadsExdm2ien.xml

- Shape -> Interlis 2:

      ogr2ogr -f "Interlis 2" LandCover.xml,RoadsExdm2ien.imd RoadsExdm2ben.Roads.LandCover.shp

- Importing multiple Interlis 1 files into PostGIS:

      ogr2ogr -f PostgreSQL PG:dbname=warmerda av_fixpunkte_ohne_LFPNachfuehrung.itf,av.imd -lco OVERWRITE=yes
      ogr2ogr -f PostgreSQL PG:dbname=warmerda av_fixpunkte_mit_LFPNachfuehrung.itf,av.imd -append

### Arc interpolation

Converting INTERLIS arc geometries to line segements can be forced by setting the configuration variable OGR_STROKE_CURVE to TRUE.
The approximation of arcs as linestrings is done by splitting the arcs into subarcs of no more than a threshhold angle. This angle is the OGR_ARC_STEPSIZE. This defaults to one degree, but may be overridden by setting the configuration variable OGR_ARC_STEPSIZE.

### OGR versions prior to 2.0

Arcs are always interpolated and the interpolation angle can be configured with the environment variable ARC_DEGREES.

### OGR versions prior to 1.11

For using the INTERLIS model (.ili) a Java interpreter is needed at runtime and ili2c.jar (included in the Compiler for INTERLIS 2) must be in the Java path.

## Other Notes

- ogrtools library includes extensions for the OGR Interlis driver
- Development of the OGR INTERLIS driver was supported by Swiss Federal Administration, Canton Solothurn and Canton Thurgovia.