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Dynamic PostGIS based layers

Contents

  1. Setting up the service
    1. Setting up the database connection
    2. Setting up the WMS configuration
    3. Setting up the database
  2. The database structure
    1. Adding new layers
    2. Adding new styles
      1. Main styles table
      2. Points
      3. Lines
      4. Polygons
      5. Texts
      6. Style components
  3. Tools
    1. Importing SLD/SE styles into the database
    2. Checking styles database

Just some background: all configuration files can now be found in the WEB-INF directory of the webapp. All paths given here are relative to this location. To start, it is recommended to extract/modify an already existing WMS configuration such as the CITE WMS setup instead of creating one from scratch.

1. Setting up the service

1.1. Setting up the database connection

In conf/jdbc create a new file (e.g. conn.xml) with the following content: 

<PooledConnection xmlns="http://www.deegree.org/jdbc">
  <Url>jdbc:postgresql://localhost/dynamic</Url>
  <User>postgres</User>
  <Password>postgres</Password>
  <PoolMinSize>5</PoolMinSize>
  <PoolMaxSize>20</PoolMaxSize>
</PooledConnection>

Now you've configured a database connection which can be used from all services that can use connections.

1.2. Setting up the WMS configuration

Open the file conf/services/wms.xml. You can use a dynamic layer anywhere were you can also use any other layer (do not use it as root layer, though). The dynamically generated layers will be inserted at the location of the dynamic layer element. A minimal configuration may look like this: 

<?xml version="1.0" encoding="UTF-8"?>
<deegreeWMS xmlns="http://www.deegree.org/services/wms" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" configVersion="0.5.0" xsi:schemaLocation="http://www.deegree.org/services/wms http://schemas.deegree.org/wms/0.5.0/wms_configuration.xsd">
  <ServiceConfiguration>

    <UnrequestableLayer>

      <Title>Root Layer</Title>
      <CRS>EPSG:31466 EPSG:31467 EPSG:31468 EPSG:4326 EPSG:25832</CRS>

      <DynamicLayer>
        <PostGIS>conn</PostGIS>
      </DynamicLayer>

    </UnrequestableLayer>

  </ServiceConfiguration>

</deegreeWMS>

What you've configured here is a dynamic PostGIS layer that is based upon the connection with ID conn. IDs are given implicitly from the file name of the connection configuration (without the .xml suffix).

1.3. Setting up the database

The database DDL script can currently only be downloaded from the deegree-core svn, it will drop and recreate the required tables.

With this, you're done and can start the WMS. Of course, you don't have layers and styles in the database yet, but we'll get to that next.

2. The database structure

In general, all IDs used are integers. The connections between the layers, styles and parts of the styles is done via these keys. The ID fields are all called id. The id fields are not mentioned below any more. By default, they are defined using a sequence.

2.1. Adding new layers

To add a new layer, simply add a row into the layers table.

The layers table has the following fields:

2.2. Adding new styles

2.2.1. Main styles table

To add a new style, simply add a row into the styles table.

The styles correspond to the SLD/SE (StyledLayerDescriptor 1.0.0/SymbologyEncoding 1.1.0) Rule construct and have the following fields:

You should either use the sld field, or type plus fk (but not both).

All of the 'symbolizer' tables (points, lines, polygons, texts) have the optional uom field, which can be used to specify the unit of measure which should be used to interpret numeric values in the actual styling information. This is based on the SE concept, and allows for pixel (which is the default), meter/metre, foot (currently not very well supported, testdata would be welcome) and mm (which is actually not contained in SE). One can get very pleasant looking, scaling maps using meter as UOM (and a metric coordinate system for the data!).

2.2.2. Points

The points table only contains one field:

2.2.3. Lines

The lines table contains the following fields:

2.2.4. Polygons

The polygons table contains the following fields:

2.2.5. Texts

The texts table contains the following fields: 

<PropertyName xmlns="http://www.opengis.net/ogc" xmlns:app="http://www.deegree.org/app">app:ortsname</PropertyName>

2.2.6. Style components

This section contains a description of the various style components, that are reused from all styles. Readers should refer to the SE specification for full documentation of the various fields. Only literal values are allowed here, no OGC filter expressions. Since the fields are fairly self-explanatory for readers familiar with SE, only deegree specifics are mentioned here.

3. Tools

To run the tools, use the d3toolbox, which can be downloaded from the artefacts server. To see which tools are available, just run the appropriate d3toolbox script in the bin directory, to run a tool, just add the tool name as argument.

3.1. Importing SLD/SE styles into the database

There is a rudimentary tool that can be used to import existing SE/SLD styles (as above from FeatureTypeStyle downwards) into the styles database. Run the toolbox with PostgreSQLImporter to get a command line help.

3.2. Checking styles database

There is a tool that tries to load all files in the database, and can be used to remove broken styles automatically. Run the toolbox with StyleChecker to get a command line help.

CategoryDeegree3

2018-04-20 12:04