Hi everyone!

I will be using the mitab C API for the first time in a week or so and I had some basic questions which might make a few of you laugh. Any help however would be appreciated. The C API documentation I will be referring to in the following questions can be found on: http://mitab.maptools.org/mitab-docs/mitab__capi_8cpp.html#1cfffe5b83810aefc5df8f9598d4ff99

Q1. What is meant by the field width? Is it the number of characters a field can hold?

Q2. The dimensions of the MBR of a text feature are defined in "ground units" in the C API documentation. What exactly is a ground unit? I did some research on this and wikipedia gave the following definition: "A ground is a unit of area used in India approximately equal to 203 square meters (2,185 ft²)". I really doubt that is what the C API documentation is referring to.

Q3.What exactly is an "interior ring" of a polygon? Is it simply a ring inside the outer ring of a polygon or is it referring to a hole?

Q4. For the following two functions it is not specified in the C API documentation what the returned value will be if the object has no geometry or the part or the point number is invalid:

Function #1:
double MITAB_STDCALL mitab_c_get_vertex_x (mitab_feature feature, int part, int vertex),

Function #2:
double MITAB_STDCALL mitab_c_get_vertex_y (mitab_feature feature, int part, int vertex)

Q5. Functions such as the one shown below return a "0-based index" for a field according to the C API documentation. Does this simply mean that the first field will have an index of 0?:

Example Function:
int MITAB_STDCALL mitab_c_add_field (mitab_handle dataset, const char *field_name, int field_type, int width, int precision, int indexed, int unique)

Like I said before any help will be aprreciated.

Regards,
Adeel.