The Text/Geography format is built on top of Comma Separated Values (CSV) files and is used to encode simple geography features such as points or lines.
Each Text/Geography file can contain either points or lines, but not a mixture of the two. The files should not have any human readable header.
Records in line files have a variable number of fields:
- the feature id,
- the number of points described;
- and the latitudes and longitudes of each point.
15,3,44.2394,20.2345,44.2932,20.0123,44.3901,19.9234
In case there is more than one record for the same feature, the behavior is unspecified.
Records in point files have 3 fields:
- the feature numerical id,
- its latitude,
- its longitude.
4,44.2394,20.2345
8,44.3901,19.9234
In case there is more than one record for the same feature, the behavior is unspecified.
The Text/Geography format is the simplest geography format that can be used to interact with Calliper TransCad. It's used extensively by those manipulating TransCad networks outside GISDK and is suitable for any exchange of simple geography data, but has never been formally specified.
In fact, TransCad's documentation isn't even compatible with the files it generates, and this has in the past caused software written by the author of this small document to break in unexpected ways.
Something in the lines of Well Known Text (WKT) – or even Well Known Binary (WKB) – may be a suitable replacement for future applications that will never interface with TransCad, mainly for being a public and well-defined format.
Documentation of Emme Free Format (EFF) files can be found on the Emme manual.