Working with the database¶

The feature database is CAMS managing the storage and access of vector data, pieces of information like sensor measurements that can be described in space with a geometric figure such as a points, lines or polygons. See http://wiki.gis.com/wiki/index.php/Vector_data_modelto read more about vector data models.

The basic piece of information of this data model is the feature, defined by a geometry that indicates unequivocally its position and shape in the world, and a set of attributes which are the characteristics associated to that location. Related features sharing a common geometry definition and attribute set are usually grouped together.

• Table of contents
• Working with the database
  • Data model
    • Dataset
    • Collection
    • Feature
  • Code architecture
    • Class diagram
    • DataServer
    • FeatureDatabase
    • StorageBackends
  • Code examples
    • Initialization
    • Inserting feature
    • Querying the database
  • Post-mission analysis

Data model¶

The CAMS database model is takes inspiration from the OGR data model and the OGC OpenPackage specification.

Dataset¶

A dataset is encompasses a set of feature collections stored in the same database or file.

Collection¶

A collection describes the characteristics of features of the same kind or category. I.e.: "Wind", "UAV state", "Liquid water content", etc. It corresponds roughly to a table in a relational database or a layer in many geographic information models.

A collection is defined by the following parameters:

1. A computer id (name_id),
2. A human-readable name,
3. An coordinate reference system as an EPSG code,
4. A geometry type (As of 12/2020 only the "point" geometry is supported),
5. A ordered set of attributes and corresponding types. Attributes can be of type int, str, float, or datetime.
6. And, optionally, a long description.

Feature¶

The collection field is used to identify the collection to with a particular field belongs; thus determining the geometry and attribute set.

General attributes, t (time) and producer , are mandatory for features generated repeatedly by UAV sensors. The time attribute is represented by a date and time (datetime.datetime in python) in Coordinated Universal Time (UTC). The producer attribute is a string.

Specific attributes are unique to a particular collection. All features of the same collection must have the same attributes, but features of different collections do not need to share specific attributes unlike general ones. For instance, a "wind" collection can have the "east" and "west" attributes to describe the wind vector components.

Code architecture¶

Class diagram
¶

DataServer¶

FeatureDatabase¶

StorageBackends¶

Code examples¶

Initialization¶

Inserting feature¶

Querying the database¶

Post-mission analysis¶