In addition to the generic FME feature attributes that FME Workbench adds to all features (see About Feature Attributes), special FME feature attributes direct the SDF3 writer as it adds features to its output files, and are used by the SDF3 reader to store the characteristics of the features it reads.
The most important of these is the fdo_type attribute, which controls the overall interpretation of the feature. The correct values for fdo_type are
- fdo_point
- fdo_multipoint
- fdo_curve
- fdo_line
- fdo_arc
- fdo_multicurve
- fdo_multiline
- fdo_curvepolygon
- fdo_polygon
- fdo_ellipse
- fdo_multicurvepolygon
- fdo_multipolygon
- fdo_null
The parameters specified for each of these values are described below.
Points
fdo_type: fdo_point
Features with an fdo_type of fdo_point contain point features.
Multipoints
fdo_type: fdo_multipoint
Features with an fdo_type of fdo_multipoint contain multiple point features.
Curves
fdo_type: fdo_curve
Features with an fdo_type of fdo_curve contain curve features consisting of curve segments. A curve segment may be a circular arc segment or a linear line segment.
Lines
fdo_type: fdo_line
Features with an fdo_type of fdo_line contain linear line features. If the writer receives a feature with the fdo_type set to fdo_line, the writer will, if possible, stroke arc segments in the feature and write the feature as a linear line.
Multicurves
fdo_type: fdo_multicurve
Features with an fdo_type of fdo_multicurve contain multiple curve features.
Multilines
fdo_type: fdo_multiline
Features with an fdo_type of fdo_multiline contain multiple linear line features. If the writer receives line features with arc segments, the writer will stroke the arc segments before writing the features to the file.
Curvepolygons
fdo_type: fdo_curvepolygon
Features with an fdo_type of fdo_curvepolygon contain polygons with inner and outer boundaries defined by curve segments. A curve segment may be a circular arc segment or a linear line segment. A curvepolygon may or may not have inner boundaries that define a hole in the polygon.
Polygons
fdo_type: fdo_polygon
Features with an fdo_type of fdo_polygon contain polygons with inner and outer boundaries defined by linear line segments. If the writer receives polygon features with arcs in the boundaries, the writer will stroke the arc segments before writing the features to the file. A polygon may or may not have inner boundaries that define a hole in the polygon.
Multicurvepolygons
fdo_type: fdo_multicurvepolygon
Features with an fdo_type of fdo_multicurvepolygon contain multiple curvepolygon features.
Multipolygons
fdo_type: fdo_multipolygon
Features with an fdo_type of fdo_multipolygon contain multiple polygon features.
Arcs
fdo_type: fdo_arc
Features with an fdo_type of fdo_arc contain arc features. Non-circular arcs will be stroked.
Ellipses
fdo_type: fdo_ellipse
Features with an fdo_type of fdo_ellipse contain elliptical features. Ellipses where the primary axis is different than the secondary axis will be stroked.
Null
fdo_type: fdo_null
Features with an fdo_type of fdo_null has no geometry associated with the feature.