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This page answers the question "What jars do I need" - the answer depends on what you are doing. This page introduces the you to the parts of the GeoTools library and how they fit together, we have isolated the parts into individual jars - so you can use just the right amount of GeoTools in your next project.
The examples (03 First Project and 04 How to Read a Shapefile) are writen with the maven build system in mind. The maven build system is very good at sorting out dependencies between lots of little jars - and is the recommended way to start using GeoTools.
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Traditionally users just dump all the jars into their IDE and have a go, please be advised that some of the jars will be in conflict.
Using maven in concert with your IDE, and looking over the pictures on this page is recommended since there are often two many jars to manage by hand. |
Meet the Library
The GeoTools library is constructed as a series of layers.
| Layer | Jar | Purpose |
|---|---|---|
| Render | gt2-render | Draw a map (just to a Graphics2D) |
| JDBC | gt2-jdbc | for reading spatial information from a database |
| Data | gt2-data | for reading spatial data |
| Main | gt2-main | implements filter, feature, etc... |
| Coverage | gt2-coverage | read raster information |
| API | gt2-api | our public interfaces |
| Referencing | gt2-referencing | defines where coordiantes show up on a map |
| Metadata | gt2-metadata | identity, description, and so on. |
Not all of these layers are provided by us - where other projects are willing to do the work we are happy to benefit.
| Project | Purpose |
|---|---|
| GeoAPI | interfaces for coordinate reference systems, geometry, etc.. |
| JTS | provides an implementation of Geometry |
This is the software stack!
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Each layer of the stack is built on the ones below it:
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Meet the Plugins
Of course that is not the complete picture - just by itself the GeoTools library does not do anything. There are plug-ins to for different data formats (so the data module can work), different coordinate reference system authorities (so the referencing module can work) and so on.
| Plugin | JDBC Layer |
|---|---|
| postgis | Work directly with a PostGIS database |
| db2 | Work directly with a DB2 database |
| oracle | Work directly with an Oracle database |
| Plugin | Data Layer |
| shape | Adds the shapefile read/write support |
| wfs | Adds WFS read/write support |
| arcsde | Communicate with ArcSDE |
| Plugin | Coverage Layer |
| geotiff | Work with geotiff rasters |
| arcgrid | Work with the arcgrid format |
| mig | Work with the MIF format |
| Plugin | Referencing Layer |
| epsg-access | Work with the offical EPSG database as shipped in Access format |
| epsg-hsql | Pure solution for working with the offical EPSG database |
| epsg-wkt | Lightweight solution working with unoffical EPSG codes |
| epsg-postgresql | Work with the offical EPSG database loaded into Postgresql |
| epsg-oracle | Work with the offical EPSG database loaded into Oracle |
Usually at least one plug-in is needed for each layer for GeoTools to do something. As an example every time you use the referencing module please make sure you have an epsg plugin around (or the referencing module will not know that "EPSG:4326" is the world as we know it).
Meet the Extensions
We have gone a bit further and implemented some interesting functionality on top of the GeoTools library. This code is kind of fun and may be useful in your own project.
| Extension | Purpose |
|---|---|
| validation | Use to define and enforce constraints on your spatial data |
| graph | Build networks from your spatial data, find the shortest route between two points |
| shapefile-renderer | A really fast renderer just for shapefiles |
| mappane | A Swing widget as an example for your own application |
How good is this Stuff
The GeoTools library is live and online! So you can check up on modules, plugins and extensions you are about to use:
This page includes a description of how good each module is (more stars is better). If there are any serious problems (ie a red star) you may want to click on the module name to find out more information.
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The Module Matrix also lists some cool unsupported stuff - this falls into the "not ready" category. |