Hi Graham, Jacques
You dont need to use the ObjectNodeX and ObjectNodeY functions, just use
the ExtractNodes() function see the exampel below
dim testobj, nytobj as object,
i,ii, NRec, NPoly as smallint,
NNodes as integer,
tabnavn as string,
aObj as alias
tabnavn = "dummy"
aObj = tabnavn + ".OBJ"
NRec = tableinfo(tabnavn, tab_info_nrows)
for i = 1 to NRec
fetch rec i from tabnavn
testobj = aobj
NPoly = objectinfo(testobj, OBJ_INFO_NPOLYGONS)
If NPoly > 1 then
For ii = 1 to NPoly
NNodes = objectinfo(testobj, (OBJ_INFO_NPOLYGONS + ii))
Nytobj = ExtractNodes(testobj, ii, 1, NNodes, True)
Insert into f_delt(obj, id) Values (nytobj, i)
Next
else
Insert into f_delt(obj, id) Values (testobj, i)
end if
next
Peter Laulund
National Survey and Cadastre, Denmark
"Jacques Paris" <[EMAIL PROTECTED]> - 01-08-99 02:23:03
Til: "Graham Smith" <[EMAIL PROTECTED]>, [EMAIL PROTECTED]
cc: (bcc: Peter Laulund/MI/KMS)
Vedrørende: RE: MI Splitting polygons
objectinfo(obj,21) or ...,obj_info_npolygons) yields the number of polygons
for the object.
e.g. if you
select * from your_table where objectinfo(obj,21)>1 into selec
you will get the table "selec" with all your multi-polygons regions
(records)
To "explode" those regions you have to write an iterative program, going
through each region and for each one reading the required info with
objectinfo(obj,21+poly_num) to get the number of nodes in each polygon
abd
objectnodeX(obj,poly_num,node_num) and objectnodeY(..) for each node
coordinates
then create a single-polygon region with these nodes.
A rather straight forward progam! Good luck.
Jacques Paris
============================================================
e-mail [EMAIL PROTECTED]
alternate [EMAIL PROTECTED]
gis activity (MapInfo mainly)
http://www.total.net/~rparis/gisproducts.htm
============================================================
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]]On Behalf Of Graham Smith
Sent: July 31, 1999 10:54 AM
To: [EMAIL PROTECTED]
Subject: MI Splitting polygons
Hi everyone,
I have a MapInfo layer containing a large number of records. Most of
the
records are single geometric shapes (polygons), but some are comprised of
geographically separate polygons that have been combined into a single
record. I need to be able to split these combined polygons so that in the
resulting table every record in the table represents a single geometric
shape (polygon).
Does anyone know how this can be done automatically using mapbasic? I
know that it can be done interactively, by drawing a shape around a polygon
in the cosmetic layer and using the "Split" command, but I have around
50,000 records in the table and it would take forever to do this manually.
Is there some way of identifying from the .MAP file whether a record
consists of more than one polygon?
Graham Smith
[EMAIL PROTECTED]
|
objectinfo(obj,21) or ...,obj_info_npolygons) yields the number of
polygons for the object.
e.g.
if you
select * from your_table where
objectinfo(obj,21)>1 into selec
you will get the table "selec" with all your
multi-polygons regions (records)
To
"explode" those regions you have to write an iterative program, going
through each region and for each one reading the required info
with
objectinfo(obj,21+poly_num) to get the
number of nodes in each polygon abd
objectnodeX(obj,poly_num,node_num) and objectnodeY(..)
for each node coordinates
then create a single-polygon region with these
nodes.
A
rather straight forward progam! Good luck.
Jacques
Paris
============================================================ e-mail [EMAIL PROTECTED] alternate [EMAIL PROTECTED] gis activity (MapInfo
mainly)
http://www.total.net/~rparis/gisproducts.htm ============================================================
|
