GRASS 5.7/6 Vector Format and API

The API is described in

source code file:
lib/vector/vectorlib.dox

Vector ASCII Format Specification

format notes here are outdated and to be merged into
vector/v.in.ascii/description.html

The ASCII format in the new version contains support for categories, z-coordinates, and the new types centroid, face, and kernel. Points and centroids are saved as one coordinate pair instead of two. File is saved in old dig_ascii directory but the name will be probably changed.

Head

The head of the file is similar as the head file of vector binary format but contains bounding box also. Key words are:

ORGANIZATION
DIGIT DATE
DIGIT NAME
MAP NAME
MAP DATE
MAP SCALE
OTHER INFO
ZONE
WEST EDGE
EAST EDGE
SOUTH EDGE
NORTH EDGE
MAP THRESH

Body

The body begins with the row:

VERTI:

followed by records of lines:

TYPE NUMBER_OF_COORDINATES [NUMBER_OF_CATEGORIES]
 X Y [Z]
....
 X Y [Z]
[ FIELD CATEGORY]
....
[ FIELD CATEGORY]

Everything above in [ ] is optional. Note the coordinate order in the old version (Y X) has been changed to (X Y [Z]).

TYPE may be:

P point (dot)
p dead point (dead dot)
L line
l dead line
B(A) boundary
b(a) dead boundary
C centroid
c dead centroid
F face (3D boundary)
K kernel (3D centroid)

Example of records:

Vector module programming example

Vector module C programming example

Vector module upgrade status

Vector upgrade status (partially outdated)

$Date$