Geoportal WebGIS framework using Python Django

Objectives:

• Develop a generic framework to set up web-based geoportals using existing open source web frameworks
• Publish independent map viewers with centralized data management
• Provide ability to automatize the discovery of multi-source Earth Observation data for individual regions

Tools:

• Interactive visualization of geospatial data based on OGC services
• ISO-compliant metadata management and publication
• Satellite scene explorer
• Time-series data extraction services

Main open source software used:

• Django Web Framework (Python) with Django REST framework and GeoDjango
• AngularJS
• OpenLayers
• Bootstrap CSS

Further information:

• Eberle et al. (2018): "Automated Earth Observation data discovery and access using open source web frameworks". Poster at EGU 2018 conference, Vienna.

Open issues:

• Provide sample database dump file
• Further source code cleanup and documentation
• Activate issues in this repository
• Provide Dockerfile

Examples

GEO-Wetlands Community Portal - Wetland observations from space

http://portal.swos-service.eu

PhaenOPT.info - phenological maps for Thuringia, Germany

http://phaenopt.info (coming soon)

GlobBiomass WebGIS

ARBIS - Assam River Basin Information System

Setup

Backend setup

# install python2 versions of pip and virtualenv

$ cd path/to/cloned-repo
# create a virtualenv
$ virtualenv --python=python2 venv
# activate the virtualenv
$ source venv/bin/activate
# install all packages listed in requirements.txt
$ pip install -r framework/requirements.txt

Database setup (with backup file)

$ createdb -U <dbUser> <database>
$ psql <database> < dump.db

Database setup (without backup file, based on Django migrations)

$ createdb -U <dbUser> <database>
$ source venv/bin/active
$ python manage.py makemigrations
$ python manage.py migrate

Frontend setup

# install npm (preferrably via distro package manager)

$ cd path/to/cloned-repo
## install all packages listed in npm-shrinkwrap.json and packages.json
$ npm install

Django setup

$ vi webgis/settings.py
Adjust DATABASES dictionary
Adjust SUBDIR according to your Apache configuration

$ python manage.py collectstatic
Yes, files can be overwritten

Apache WSGI

$ vi index.wsgi
Adjust your local virtual environment directory
Adjust PYTHONPATH to framework and webgis directory

$ vi /etc/apache2/sites-available/default
WSGIScriptAlias /swos2 /home/sibessc/workspace/swos/master/framework/index.wsgi
Alias /swos2/static/ /home/sibessc/workspace/swos/master/framework/static/

$ sudo apache2ctl -k graceful
Restart apache "gracefully"

Django Configuration

Prior to any mapviewer request you need to edit the mapviewer and adjust the template selection, because complete path is stored in the database!

Frontend maintenance

For a list of required, external JavaScript libraries, see packages.json. For a detailed list of required, external JavaScript libraries and their dependencies, including exact version numbers, see npm-shrinkwrap.json. For a list of actually included JavaScript and CSS files, see framework/mapviewer/assets.py.

Required JavaScript and CSS files are bundled and minified via the Django app "django-assets". The configuration of these bundles is done in framework/mapviewer/assets.py, Django is configured to search in framework/static and in node_modules for the given files. Bundles are stored in static/build, which is ignored by git.

Most libraries only have JavaScript or CSS code, but some also come with fonts or images. These additional files have been copied from the libraries' node_modules to our static directory, while keeping the directory structure intact. At the moment, this applies to the following libraries:

• Bootstrap
• Font Awesome
• Fancybox

Debugging

During development, bundling and minification might be undesired. It can be easily disabled by setting ASSETS_DEBUG=True in settings.py. In production mode, this should be changed to FALSE.

Library installation/updates

When installing/updating a library, it is necessary to check, if the library has font files, images etc. that have to be copied into our static directory.

# installing a library + saving in npm-shrinkwrap.json and packages.json
npm install --save "[email protected]"

# check, which packages can be updated
# current: installed version
# wanted: latest version taking version constraint from packages.json into account
# latest: actual latest version (might have breaking changes!)
npm outdated

# updating a library to the latest minor + saving in npm-shrinkwrap.json and packages.json
npm update --save "jquery"

Bundling/Bundle configuration

To include JavaScript or CSS files, they have to be added to the right bundle in framework/mapviewer/assets.py. The idea is to have 4 file lists containing all files required by all Mapviewers:

• baseVendorJs: external JavaScript files
• baseAppJs: our own AngularJS files
• baseVendorCss: external CSS files
• baseAppCss: our own CSS files

These 4 lists serve as the base for defining bundles specific for a Mapviewer. E.g. bundles for a Mapviewer called "foo" would look like this:

• baseVendorJs + foo-specific JS files => fooVendorJsBundle
• baseAppJs + foo-specific app JS files => fooAppJsBundle
• ...

Anchors to wetlands and products

#/wetland/4/ --> open wetland with id 4
#/wetland/4/product/ --> open wetland with id 4 and select products
#/wetland/4/product/1932 --> open wetland with id 4, select product, add layer with id 1932 and open menu
#/wetland/4/product/2551_1932 --> open wetland with id 4, select products, add layer with id 2551 and 1932 and open menu (type (e.g. "product") should fit to last layer id --> #/wetland/4/externaldb/1932_2551 )

Anchors to story lines

#/storyline/2 --> open story line with id 2
#/storyline/2/2 --> open story line with id 2 part 2