H2GIS

H2GIS is a spatial extension of the H2 database engine in the spirit of PostGIS. It adds support for managing spatial features and operations on the new Geometry type of H2, the Open Geospatial Consortium (OGC) Simple Features for SQL (SFSQL) functions and additional spatial functions that we (the CNRS) develop.

H2GIS is the root project for the new OrbisGIS data management library. It contains tools to execute geometry analysis and read/write geospatial file formats.

H2GIS is licensed under the LGPL 3 license terms.

h2gis-functions

h2gis-functions is the main module of the H2GIS distribution. It extends H2 by adding spatial storage and analysis capabilities,including

• a constraint on Geometry data type storing POINT, CURVE and SURFACE types in WKB representations
• spatial operators (ST_Intersection, ST_Difference, etc.)
• spatial predicates (ST_Intersects, ST_Contains, etc.)
• additional spatial SQL functions that are not in Simple Features for SQL (SFSQL)

Ex: ST_Extent, ST_Explode, ST_MakeGrid

It contains a set of driver functions (I/O)) to read/write file formats such as .shp, .dbf, .geojson, .gpx

This I/O package include 2 implementation of TableEngine that allow you to immediatly 'link' a table with a shape file.

It include also file copy functions (import):

• SHPREAD( ) and SHPWRITE( ) to read and write Esri shape files.
• DBFREAD( ) and DBFWRITE( ) to read and write DBase III files.
• GeoJsonRead() and GeoJsonWrite() to read and write GeoJSON files.
• GPXRead() to read GPX files.

Usage

For now, H2GIS requires Java 6. Run maven clean install -P standalone in the H2GIS's root directory.

In the folder h2gis-dist/target/ you will find a zip file h2gis-standalone-bin.zip.Unzip the file then open h2gis-dist-xxx.jar It will open a browser based console application.

~ $ unzip h2gis-standalone-bin.zip

~ $ cd h2gis-standalone

~/h2gis-standalone $ java -jar h2gis-dist-xxx.jar

Click Connect in the web interface

Create a database and run the following commands to add spatial features (do it only after the creation of a new database):

Initialize the H2GIS extension

To initialize the H2GIS extension apply the SQL syntax:

CREATE ALIAS IF NOT EXISTS H2GIS_SPATIAL FOR "org.h2gis.functions.factory.H2GISFunctions.load";
CALL H2GIS_SPATIAL();

When the functions are installed you can open a shapefile by calling the following SQL request:

CALL FILE_TABLE('/home/user/myshapefile.shp', 'tablename');

This special table will be immediatly created (no matter the file size). The content will allways be synchronized with the file content.

You can also copy the content of the file into a regular H2 table:

CALL SHPREAD('/home/user/myshapefile.shp', 'tablename');

Or copy the content of a spatial table in a new shape file:

CALL SHPWRITE('/home/user/newshapefile.shp', 'tablename');

Contributing

For legal reasons, contributors are asked to provide a contributor license agreement. We invite each contributor to send a mail to the H2GIS developer mailing list.

The mail need to include the following statement:

"I wrote the code, it's mine, and I'm contributing it to H2GIS for distribution licensed under the LGPL 3.0."

For a significant contribution, send a PR on GitHub and refer it in your message. For a single contribution join a patch to your mail.

Acknowledgements

The H2GIS team utilizes open source software. Specifically, we would like to thank :

• Thomas Mueller and Noel Grandin from the H2 database community.
• Martin Davis from the JTS Topology Suite community.

Supporters

Many thanks for those who reported bugs or provide patches...

• Steve Hruda aka shruda PR #453
• Ivo Šmíd aka bedla PR #556, PR #695
• Michaël Michaud PR #778

Team

H2GIS is composed of four qualified professionals in GIS and informatic sciences.

• Erwan Bocher leads the project.
• Nicolas Fortin is the lead programmer.
• Sylvain Palominos is the lead programmer of the OrbisGIS platform.
• Gwendall Petit is in charge of the documentation and manages all public relations with the community users.