WPS download community module

WPS download module provides some useful features for easily downloading Raster or Vectorial layer as zip files, also controlling the output file size.

Installing the WPS download module

  1. Download the WPS download module from the nightly GeoServer community module builds.

    Warning

    Make sure to match the version of the extension to the version of the GeoServer instance.

  2. Extract the contents of the archive into the WEB-INF/lib directory of the GeoServer installation.

Module description

This module provides two new WPS process:

  • gs:Download : this process can be used for downloading Raster and Vector Layers
  • gs:DownloadEstimator : this process can be used for checking if the downloaded file does not exceeds the configured limits.

Configuring the limits

The first step to reach for using this module is to create a new file called download.properties and save it in the GeoServer data directory. If the file is not present GeoServer will automatically create a new one with the default properties:

# Max #of features
maxFeatures=100000
#8000 px X 8000 px
rasterSizeLimits=64000000
#8000 px X 8000 px (USELESS RIGHT NOW)
writeLimits=64000000
# 50 MB
hardOutputLimit=52428800
# STORE =0, BEST =8
compressionLevel=4

Where the available limits are:

  • maxFeatures : maximum number of features to download
  • rasterSizeLimits : maximum pixel size of the Raster to read
  • writeLimits : maximum pixel size of the Raster to write (currently not used)
  • hardOutputLimit : maximum file size to download
  • compressionLevel : compression level for the output zip file

Note

Note that limits can be changed when GeoServer is running. Periodically the server will reload the properties file.

Download Estimator Process

The Download Estimator Process checks the size of the file to download. This process takes in input the following parameters:

  • layername : name of the layer to check
  • ROI : ROI object to use for cropping data
  • filter : filter for filtering input data
  • targetCRS : CRS of the final layer if reprojection is needed

This process will return a boolean which will be true if the downloaded file will not exceed the configured limits.

Download Process

The Download Process calls the Download Estimator Process, checks the file size, and, if the file does not exceed the limits, download the file as a zip. The parameters to set are

  • layername : name of the layer to check
  • format : format of the final file
  • ROI : ROI object to use for cropping data
  • filter : filter for filtering input data
  • targetCRS : CRS of the final layer if reprojection is needed

The available format for the process are:

  • Raster:

    • image/tiff

  • Vector:

    • application/json
    • application/wfs-collection-1.1
    • application/wfs-collection-1.0

  • Both

    • application/zip

The result is a file to download.