FME considers a TDRBM II dataset to be a collection of TDRBM II files contained in a single folder. The TDRBM II writer creates and writes feature data to the folder specified by the DATASET directive.
Existing TDRBM II files with the same file base name as the source file base name are overwritten with the new feature data.
Creating TDRBM II entities which contain annotation records requires the linking of source annotation features to source geometric feature with a potentially many to one relationship. This is accomplished by matching the ID attribute value of source annotation features to the ID attribute of a source geometric feature (point, line or polygon). To produce meaningful results, the following two conditions must be met:
- The Id attribute value of the source annotation feature must equal the Id attribute of the source geometric feature.
- Features received by the writer must arrive in sorted order based Id value.
Orphan annotation features, that is, annotation features not specifying an Id value or annotation features with an Id value not equal to the “current” geometric feature Id value cannot be written and are dropped. Discarding orphan text features is a consequence of the TDRBM II format, since it does not support “standalone” annotation records. The result is that orphan annotation features cannot be written to file as entities.
Producing a meaningful TDRBM II file output will require setting up a custom mapping file that describes the details of your input schema for the following reasons:
- Generic (automatic) translations usually work for most formats because they are so simple. (If a road has an attribute “length” in the source, it makes sense to make an attribute called “length” in the destination.) However, TDRBM II is a special case. TDRBM II contains numerous output format attributes which make a "best guess" impossible. Translating most formats does not require the understanding of the output format schema, just knowledge of it.
- TDRBM II has numerous predefined attributes and values that features can have. When FME is given a source dataset without any indication of which attributes in the source data should be used to fill in the required attribution in the output TDRBM II file, most of this information will be lost. (There is no way to “guess” at the Logical Level value for any given entity when all it is given is a source file with no knowledge of the meaning of the schema or input data.) Therefore, an "automatic" translation will usually not generate anything useful. What needs to happen is that a user needs to create a custom mapping file that tells the FME where to find all the required TDRBM II data within their specific source dataset.