Datasources
Introduction
The datasource defines the source of the data and the way the data is stored, styled and retrieved. The data source understands where data comes from and how to keep datasets update. A datasource can have multiple datasets, but a dataset refers only to one datasource.
Each datasource has a coordinate system. During import the imported geometries are transformed to the coordinate system of the datasource. GeolinQ supports all coordinate systems of the EPSG database. The EPSG Geodetic Parameter Dataset is maintained by the Geodesy Subcommittee of the IOGP Geometrics Committee and contains most of the coordinate systems in the world (more than 5000).
The datasource uses datasets to store the data and class definitions to define the dataset structure. Depending on the type of datasource, the class definitions can be generated from the external datasource or have to be created manually. A datasource can also contain user-defined import formats, quantities, colour scales, styles and maps.
It is possible to make a datasource dependent on other datasources. This means that it is possible to get access from one datasource to the type and dataset definitions and datasets of another dependent datasource.
Each datasource type is described in detail below:
Catalog datasource
The catalogue data source stores entity, feature and point datasets imported from file. The following input formats are supported for point datasets:
- Tabular ASCII
- LAS
- GeoTIFF
The following input formats are supported for feature datasets:
- Shape
The type class definitions and dataset definitions in a catalogue datasource can be created manually or can be imported from a catalogue datasource file. The structure of the data file has to be mapped to the type class of the selected dataset.
WFS datasource
A WFS datasource is defined by the URL to the external WFS. The table structure in GeolinQ is created from the feature type definitions published by the external WFS (from the DescribeFeature request). The type class definitions are generated from the table definitions or can be created manually. Feature datasets are created by mapping the table columns generated from WFS to the type class attributes.
< Features are harvested from the external WFS (using GetFeature request) and stored in the feature datasets of the WFS datasource. A bounding box can be used as a spatial constraint. GeolinQ supports WFS 1.1.0 and WFS 2.0.0.
GML datasource
A GML datasource is defined by the URL to the XSD that defines the structure of the GML file. The table structure in GeolinQ is created from the GML XSD. The type class definitions are generated from the table definitions or can be created manually. Feature datasets are created by mapping the table columns generated from the GML XSD to the type class attributes.
The features from the imported GML file are stored in the feature datasets. The GML file can be a single GML file or a zipfile containing multiple GML files. The individual GML files must validate against the XSD that was used to create the datasource. GML version 2 and GML version 3 (SF) are supported. Note: GML is not fully supported. All configured datasources delivered by IntellinQ are tested on completeness of the data structures.
XML datasource
A XML datasource is defined by the URL to one or more XSD's that defines the structure of the XML file. The table structure in GeolinQ is created from the XSD. The type class definitions are generated from the table definitions or can be created manually. Feature datasets and entity datasets are created by mapping the table columns generated from the XSD to the type class attributes.
The features and entities from the imported XML file are stored in feature datasets and entity datasets. The XML file can be a single XML file or a zipfile containing multiple XML files. The individual XML files must validate against the XSD that was used to create the datasource.
Note: XML version 1.1 is not fully supported. All configured datasources delivered by IntellinQ are tested on completeness of the data structures.
Database datasource
A database datasource is defined by the database credentials to the remote database. The type class definitions can be generated from the table definitions or can be created manually. Feature and entity datasets are created by mapping the table and table columns on the remote database to the type classes and type class attributes in GeolinQ.
Feature datasets gives access to the features stored in the remote database via a database link. Entity datasets gives access to the entities stored in the remote database via a database link. Features and entities are not stored in the GeolinQ database. Features and entities cannot be updated or deleted.
GeolinQ supports Oracle and PostgreSQL as remote databases.