NAME
polygon1.2, polygon_schema - schema for storage of polyline data
SUPPORT
Contributed code: NO BRTT support.
THIS PIECE OF SOFTWARE WAS CONTRIBUTED BY THE ANTELOPE USER COMMUNITY. BRTT DISCLAIMS ALL OWNERSHIP, LIABILITY, AND SUPPORT FOR THIS PIECE OF SOFTWARE.
FOR HELP WITH THIS PIECE OF SOFTWARE, PLEASE CONTACT THE CONTRIBUTING AUTHOR.
DESCRIPTION
The schema polygon1.2 provides the relations (tables) polygon and remark.
FIELDS
-
pid
unique id. (polygon ID)
-
pname
name of polygon. Text. Pname and ptype together must be unique (primary key)
-
ptype
polygon type. Can be used to distinguish several types of polygons (Continents, Countries, etc...). Pname and ptype together must be unique (primary key).
-
closed
closed flag. Used to distinguish between open (polylines, lines, points) and closed polylines (polygons).
-
level
idea from GSHHS. could be used to distinguish polygons of increasing detail.
-
area
Area of the polygon in km^2. For reference only, not necessary.
-
west, east, north, south
These 4 fields befine the bounding box of a polygon. Used for preselection to speed up searching of point-inclusion or similar tasks.
-
npoints
number of vertices.
-
ftype
storage type.
Currently, the following types are allowed:
s4 -> sun 4 byte integer
i4 -> intel order 4 byte integer
t4 -> sun 4 byte float
u4 -> intel order 4 byte float
Note: when using integer storage, all data values should be multiplied with 1e6 to preserve some of the initial accuracy. As this schema is designed to hold polygon coordinates in lat/lon resolution, this should be precise enough.
-
dir,dfile,foff
Identify actual data storage
-
auth
Author.
-
commid
remark pointer
-
lddate
Modification time
SEE ALSO
dbschema(5), dbhelp(1), dbdesign(1)
AUTHOR
Nikolaus Horn, 2003
ZAMG / Vienna, Nikolaus.Horn@zamg.ac.at
Antelope User Group Contributed Software