Solution or Workaround
The data does not link properly and the item values are not as expected when using a relate or JOINITEM between the FAT's and INFO tables for converted SDTS files.
The SDTS/DLG JOIN file has a 1:n relationship to records in the FAT.
The example below illustrates SDTS files being accessed for arc data. The example is basically the same for polygon features as well.
Let's say the SDTS/dlg roads coverage name is TRST011. There are 2 sets of attributes for each line feature. Attributes will be in files TRST011.ARDM and TRST011.ARDF.
The TRST011.AJOIN has two records for each TRST011-id. Each record stores the name of the file, referenced by extension (ARDM) and the record number in that file that contains the features attributes.
Record TRST012-ID MODN_NAME MODN_ID
1 1 ARDF 6707
2 1 ARDM 1877
Arcplot: items TRST011.ardm info
COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME
1 MODN_ID 6 6 I - -
7 ROUTE_NUMBER 7 7 C - -
14 ROUTE_TYPE 9 9 C - -
We want to get at the route numbers for the roads features. We can do this with the keyfile option, like this:
Arcplot: mapext TRST011
Arcplot: res TRST011.ajoin INFO modn_name cn 'ARDM'
Arcplot: res TRST011 arcs keyfile TRST011.ajoin TRST011-id
Arcplot: relate restore TRST011.rel
Arcplot: list TRST011 arcs ajoin//modn_name
Arcplot: list TRST011 arcs ajoin//ardm//route_number
You'll get this:
1 I 40
2 I 40
3 I 40
4 I 40