This topic introduces the terms that are used in Lindorm Ganos.
Spatio-temporal geometries in Lindorm Ganos consist of the following items:
Objects of spatio-temporal geometries
Vector data, such as points, lines, and planes
Spatio-temporal data that consists of vector data and temporal attributes. This type of data is also referred to as spatio-temporal trajectory data.
Operations that are related to objects of spatio-temporal geometries, such as spatial relationship verification
Lindorm Ganos improves the speed of data queries by using spatio-temporal indexes. Spatio-temporal indexes are stored as rowkeys in Lindorm Ganos. For more information, see Create an index table.
A spatio-temporal relationship describes the relative locations of two geometries in time and space. Typical spatio-temporal relationships include INTERSECT, DISJOINT, OVERLAP, and CONTAIN. In most cases, geofencing identifies the relationships of the geo-fences of an area to an object. The object can be a point, a line, or a plane. If the object is within the geo-fences, the area contains the object. If the object is outside the geo-fences, the area and the object are disjoint. Lindorm Ganos supports Common Query Language (CQL) that can be used to define spatio-temporal relationships. For more information, see Query spatio-temporal objects.
Open Geospatial Consortium (OGC) is an international voluntary consensus standards organization. It defines a set of standards for data modeling and related operations. Geographic information system (GIS) vendors develop their GISs based on the standards. This ensures spatial data interoperability.
Lindorm Ganos SDK is developed based on GeoTools. GeoTools is a library that provides tools for you to process geospatial data. GeoTools complies with OGC standards and can interact with standard OGC data models and interfaces. A large number of GISs are developed based on GeoTools. For more information, visit https://geotools.org/.
A geometry in OGC is defined as a spatial object, such as a point, a line, or a plane. A geometry contains only location information of a spatial object. A geometry does not contain attribute information. GeoTools provides tools for you to build geometries when you use Lindorm Ganos.
SimpleFeature specifies simple objects. A simple object contains geometries and other attributes. A trajectory point is a simple object. The simple object contains the location information, temporal information, and other attributes of the trajectory point. The temporal information is also part of the attribute information.
CQL is a language that is defined by OGC to support geospatial data queries. Extended common query language (ECQL) is an extended version of CQL. In most cases, ECQL is used to define filters based on SQL-like WHERE clauses. ECQL uses well-known text (WKT) to filter the objects that you want to manage. For more information, see Query spatio-temporal objects. CQL that is used in this user guide refers to ECQL.
WKT is a text markup language that is defined by OGC to describe spatial objects. For example, you can use POINT(0,0) to represent a point. WKT is widely adopted in query statements and is easy to understand. CQL and ECQL also use WKT to describe spatial objects. For more information about WKT, visit http://www.opengeospatial.org/standards/wkt-c.
Well-known binary (WKB) is a language that is defined by OGC to mark geometries based on serialized bytes. The size of WKB data is smaller than that of WKT data. You can use WKB to transmit data. GeoTools provides a tool for you to convert data between WKB and WKT.