Getting started with django-restframework-gis on Windows 10

Question

I have some experience with Python-Django including its REST framework, a reasonable understanding of geographic information (and what GIS is about) and about databases, and I would like to develop a "geo-aware" REST service on my Windows machine based on Django. The application shall be limited to the REST service; visual exploration and other stuff shall be developed independently. Side-remark: once my application is running, it will be ported onto a Linux machine and PostGIS will then be used instead of SpatialLite.

After several hours of web-searching, I still haven't come up with a good "Quickstart" guide. There are many tutorials and docs about various aspects related to my task, but they either refer to Linux, or their installation instructions are outdated. Here is what I have done so far:

1) I use miniconda and Pycharm

2) I created a new virtual environment like so:

conda create -n locations pip numpy requests
activate locations
conda install -c conda-forge django djangorestframework djangorestframework-gis

3) I set-up the new Django project and my application and performed a database migration:

python [path-to..]\django-admin.py startproject locations
cd locations
python [path-to..]\django-admin.py startapp myapp
cd ..
python manage.py migrate

4) I added "rest_framework" and "myapp.apps.MyAppConfig" to the APPLICATIONS in settings.py

5) I stopped reading the general django-restframework tutorial and began searching for django-restframework-gis specific information. What I understood from this is that I need to enhance my SQLite database to become a SpatialLite database. Windows binaries for SpatialLite are available at gaia-sins -- but which of these do I really need? I downloaded the mod_spatialite-4.3.0a-win-x86.7z file and unpacked it, and I added SPATIALITE_LIBRARY_PATH= '[path-to..]\mod_spatialite-4.3.0a-win-x86\mod_spatialite.dll' to my settings.py.

What comes next?

Specific questions:

1) Do I really need to upgrade my SQLite database if I am not planning to store geospatial information but merely build a REST service to deliver information in GeoJSON which is coming from other sources (for example weather model output in netcdf data format)? Or would it suffice to describe my Django model in this case and simply ignore any database-related issues?

2) What is the minimum code to get the basic "wiring" done? This could be an extremely simple service which would accept a lat/lon coordinate as parameter in the URL and return this location in GeoJSON format. Such code should highlight the differences between using the "normal" django-restframework from the gis version. Once I have this, I will probably find my way through the existing documentation (for example Miguel Grinberg Tutorial or GitHub description).

Answer 1

OK, after another day of searching and experimenting, I acknowledge that this has been the wrong question to ask - therefore I answer myself and close this issue.

Apparently, I have been to naive about setting up a "geo-aware" service, thinking that I can get away with a special datatype or two for coordinates, and a special kind of serializer for GeoJSON - and, if really necessary, with a geo-enabled database.

Turns out, that what I want to do in the end, is a GeoDjango application (even if I will use only a tiny fraction of what GeoDjango can do), and so the GeoDjango docs are the place to start from, and in particular their installation guide.

The story isn't over yet as I am still having troubles to load the required libraries from Django, but the direction is clearer now.

More specifically, the issue I ran into wasn't primarily a SpatiaLite issue. I was able to install SpatiaLite and enhance an existing sqlite database by running SELECT load_extension('mod_spatialite'); SELECT InitSpatialMetaData(); (see also this post. Django (python manage.py check) complained about not finding the gdal library, and once it found it, it was the wrong version. The GeoDjango docs report that this is indeed the most common problem when installing GeoDjango. It would be helpful if the error messages from ctypes were a bit more verbose to make it easier to search for solutions. It took several hops across various web sites and an extra print statement in the ctypes init.py file, before I found out that one needs to match the version of gdal, the version of python, and the compiler (DLL hell this was called by someone).

Another part of the confusion arises from the manifold dependencies among the various required "geo packages". For example, SpatiaLite already comes with a gdal library, so why the need for installing gdal separately? Indeed, the GeoDjango docs recommend to work with OSGEO4W, because this program suite bundles everything together. Yet, this is not trivial if one starts from a system where OSGEO4W and Python/Django have been installed independently. This is the situation I start from. I installed OSGEO4W primarily to work with QGIS, and I installed Python and Django for other tasks. The realisation that the two must be linked for a GeoDjango application only came afterwards. I might need to start from scratch, but it would be good to know if people have been successful in a Windows 10, x64 environment with Python >= 3.4 recently.