Connectors > Smallworld

The DTS Smallworld Connector can access access geometries in the native Smallworld storage formats when streaming data from Collections and exchanges them using its own Magik wrappers for Method/Procedure Calls.

Here are the mappings:

Smallworld Geometry (DS type)	DTS Magik Wrapper (DTS Type)	GeoJson Geometry Type
point/simple_point	dts_point (DTS_POINT_GEOMETRY)	Point
chain/simple_chain	dts_chain (DTS_LINE_GEOMETRY / DTS_MULTILINE_GEOMETRY)	LineString / MultiLineString (+ DTS Corrections)
area/simple_area	dts_area (DTS_AREA_GEOMETRY / DTS_MULTIAREA_GEOMETRY)	Polygon / MultiPolygon (+ DTS Corrections)
text	dts_text (DTS_ANNOTATION_GEOMETRY)	Point (+ DTS Extras)

Smallworld differentiates between networked (topologically embedded) and simple (with no topology) geometries. The Smallworld Connector removes that distinction, as there is no standard for codifying topological data. It is still available in raw form if desired.

Smallworld chain and area geometry objects can encode multiple disconnected lines and polygons respectively, so they can result in the simple or "Multi" variant as they are streamed out.

When accessing Collections with geometry fields through the Smallworld Connector, the geometries are automatically transmuted through their respective DTS Magik Wappers and serialized as DTSGeoJson - no extra action is needed.

When using geometries within Method or Procedure arguments or results, the respective items must be registered with their DTS Type (see Method/Procedure Calls). They will receive and provide geometry data in the DTS Magik Wrapper format. For convenience, the DTS Magik Wrapper exemplars provide the following methods:

▪new_from(<a_geom>) : creates a new instance of a DTS Magik Wrapper with all the usable characteristics of the input geometry. Both ds and pseudo geometries are accepted.

▪as_pseudo_[point|chain|area|text]() : transforms the DTS Magik Wrapper object into the corresponding pseudo geometry (pseudo_point, pseudo_chain, pseudo_area, pseudo_text).

Smallworld geometries can encode more information than standard GeoJson can accommodate, so the Connector uses DTS Geometry Corrections and Extras to include that data:

▪(simple_)points can be oriented in Smallworld. The Connector uses the DTSGeoJson orientation field to encode this information.

▪texts are oriented points with extra information like justification and the actual content string. This extra information is placed in the extras field of the DTSGeoJson.

▪(simple_)chains and (simple_)areas can contain sectors that are not straight line strings. These will be approximated for standard use and the exact representation included in the DTSGeoJson corrections field as follows:

Smallworld Sector Type	Interpretation	Correction Line Type
sector	Basic sector, represents a straight line string	none (LINE_STRING*)
arc	Single elliptical arc	CP_ARCS or NURBS **
circle	Circle	CIRCLE
rational_b_spline	Rational B-spline	NURBS

sector_z is not currently supported (i.e. only 2D geometries are currently supported)

* LINE_STRING corrections are not produced by this connector or any of the other standard connectors. It exists for extensions and optimization.

** If the arc is circular, it results in a CP_ARCS correction, otherwise it's encoded as NURBS. Multiple CP_ARCS corrections may be compounded into a single one.