Heroku GeoDjango issues with missing GDAL (and possibly GEOS)

Question

I'm working on a GeoDjango application and am using Heroku (with a Heroku-16 stack) as my platform.

I am following the instructions found here, which specify the following:

If your application requires geo libraries, experimental support for a handful of these libraries are available:

• GDAL v2.2.1 (v1.11.5 for cedar-14)
• Geos v3.6.2 (v3.4.2 for cedar-14)
• Proj v4.9.3 (v4.8.0 for cedar-14)

To make these libraries available to your application, simply set the BUILD_WITH_GEO_LIBRARIES environment variable:

$ heroku config:set BUILD_WITH_GEO_LIBRARIES=1

During your next build, these libraries will be downloaded and installed. In your Django settings.py, also add the following:

import dj_database_url
DATABASES['default'] = dj_database_url.config()
DATABASES['default']['ENGINE'] = 
'django.contrib.gis.db.backends.postgis'

GDAL_LIBRARY_PATH = os.getenv('GDAL_LIBRARY_PATH')
GEOS_LIBRARY_PATH = os.getenv('GEOS_LIBRARY_PATH')

This will ensure that Django can find the GEOS libraries that are installed.

I have set the env variables in Heroku:

However, I have found that this isn't making a difference when it's time to deploy:

2017-09-23T19:29:55.142378+00:00 app[web.1]:     % '", "'.join(lib_names)
2017-09-23T19:29:55.142414+00:00 app[web.1]: 
django.core.exceptions.ImproperlyConfigured: Could not find the GDAL 
library (tried "gdal", "GDAL", "gdal2.1.0", "gdal2.0.0", "gdal1.11.0", 
"gdal1.10.0", "gdal1.9.0"). Is GDAL installed? If it is, try setting 
GDAL_LIBRARY_PATH in your settings.

Here's my requirements.txt:

dj-database-url==0.4.1
Django==1.11.5
gunicorn==19.6.0
psycopg2==2.6.2
pytz==2017.2
whitenoise==3.2

The only anomaly I have here is that I'm using Django 1.11.5 instead of what the default was with Heroku's Django project template, which is 1.11.1. This was to fix a problem that kept the project from working that was patched.

Procfile is:

web: gunicorn tagging_tracker_backend.wsgi

runtime.txt is:

python-3.6.2

The Github repo is at this link.

Answer 1

Heroku documentation says that:

Note: This feature(BUILD_WITH_GEO_LIBRARIES) is only known to work well on cedar-14. We are working to ensure that it works properly on heroku-16, slowly.

https://devcenter.heroku.com/articles/python-c-deps#geodjango-application-libraries

In order to use cedar-14:

$ heroku stack:set cedar-14 --app YOUR_APP 

Answer 2

1) Change your Django settings.py:

Before:

GDAL_LIBRARY_PATH = os.getenv('GDAL_LIBRARY_PATH')
GEOS_LIBRARY_PATH = os.getenv('GEOS_LIBRARY_PATH')

Now:

GDAL_LIBRARY_PATH = os.environ.get('GDAL_LIBRARY_PATH')
GEOS_LIBRARY_PATH = os.environ.get('GEOS_LIBRARY_PATH')

2) Set config var:

$ heroku config:set BUILD_WITH_GEO_LIBRARIES=1

3) Change Heroku's stack:

$ heroku stack:set cedar-14