django-rgd 0.2.10

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Resonant GeoData Core Application

The core Resonant GeoData (RGD) app containing file and permissions management as well as spatial models. Each of the other RGD apps depend on the core functionality built here.

Installation

pip install --find-links https://girder.github.io/large_image_wheels django-rgd

It is necessary to use a postgis database with the RGD apps. To do so, set your database ENGINE to django.contrib.gis.db.backends.postgis.

Add RGD to your INSTALLED_APPS:

INSTALLED_APPS += [
    'django.contrib.gis',
    'rgd',
]

MIDDLEWARE += ('crum.CurrentRequestUserMiddleware',)

REST_FRAMEWORK['DEFAULT_AUTHENTICATION_CLASSES'] += ('rest_framework.authentication.TokenAuthentication',)

(note that RGD requires django-crum middleware.)

It is also necessary to configure GDAL in your project settings:

try:
    import re

    import osgeo

    libsdir = os.path.join(os.path.dirname(os.path.dirname(osgeo._gdal.__file__)), 'GDAL.libs')
    libs = {re.split(r'-|\.', name)[0]: os.path.join(libsdir, name) for name in os.listdir(libsdir)}
    GDAL_LIBRARY_PATH = libs['libgdal']
    GEOS_LIBRARY_PATH = libs['libgeos_c']
except Exception:
    pass

Configurations

The RGD core app has a few optional settings:

• RGD_GLOBAL_READ_ACCESS: option to give all users access to files that lack permissions (otherwise only admin users can access these files)
• RGD_FILE_FIELD_PREFIX: the path prefix when uploading files to the project's S3 storage.
• RGD_AUTO_APPROVE_SIGN_UP: automatically approve all user sign ups.
• RGD_AUTO_COMPUTE_CHECKSUMS: automatically compute checksums for all ChecksumFile records (default False)
• RGD_TEMP_DIR: A temporary directory for working files
• RGD_TARGET_AVAILABLE_CACHE: The target free space to remain for the cache in Gigabytes (default 2).
• RGD_REST_CACHE_TIMEOUT: the time in seconds for the REST views cache (for endpoints that are cached).
• MEMCACHED_USERNAME, MEMCACHED_PASSWORD, and MEMCACHED_URL: use if hosting a memcached server to set the default django cache.
• RGD_SIGNED_URL_TTL: The time in seconds for which URL signatures are valid (defaults to 24 hours).
• RGD_SIGNED_URL_QUERY_PARAM: The signature querystring variable name (defaults to signature).

Models

• ChecksumFile: the central file storage model. Supports uploaded files, S3 URLs, and http URLS.
• Collection and CollectionPermission: for grouping files and controlling permission groups on those groups.
• SpatialEntry: the core model for indexing spatial metadata. This is intended to be inherited from but also provides a robust search filter.
• SpatialAsset: a simple spatial model for registering any collection of files with manually inputted spatial metadata.
• WhitelistedEmail: a model for pre-approving users for sign up.

The core RGD app is intended to be inherited from for developing domain-specific geospatial models. For instance, we will demo the implementation of the simple SpatialAsset model shipped in this app.

We can develop a new model on top of django-rgd through the inheritting the core SpatialEntry model and using a few mixin classes from django-rgd. This new model will represent a collection of files with some spatial reference.

from django_extensions.db.models import TimeStampedModel
from rgd.models import ChecksumFile, SpatialEntry


class SpatialAsset(SpatialEntry, TimeStampedModel):
    """Any spatially referenced file set."""
    files = models.ManyToManyField(ChecksumFile, related_name='+')

Just like that, you now have a way to associate a set of files to any geospatial location. To populate data in this model, first create ChecksumFile records, then create a new SpatialAsset populating the fields defined from SpatialEntry: acquisition_date, footprint, outline, and instrumentation.

Management Commands

The core app has two management commands:

• rgd_s3_files: used to ingest ChecksumFiles from S3 or Google Cloud storage.
• whitelist_email: pre-approve users for sign-up.

Use the --help option for more details.