Hello Mustafa, Since your working with land parcels, I guess you meant region/polygon rather than polyline? Here is a MB implementation of a clockwise test function. You simply pass in the object and the part number (to handle multi-polygon regions) and it returns whether the polygon is clockwise as TRUE or FALSE.
Regards, Warren Vick Europa Technologies Ltd. http://www.europa-tech.com Tel: +44 (0)20 8398 3955 x201 ---8<--Cut here--8<--- function IsClockwise(byval TestObj as object, byval Part as smallint) as logical dim NrPnts, i as integer dim a, x, y, Old_x, Old_y as float dim rc as logical rc = FALSE NrPnts = objectinfo(TestObj, OBJ_INFO_NPOLYGONS+Part)-1 Old_x = objectnodex(TestObj, Part, 1) Old_y = 0.0 a = 0.0 i = 1 while i <= NrPnts i = i + 1 a = a + (Old_x - objectnodex(TestObj, Part, i)) * (Old_y + objectnodey(TestObj, Part, i) - objectnodey(TestObj, Part, 1)) Old_x = objectnodex(TestObj, Part, i) Old_y = objectnodey(TestObj, Part, i) - objectnodey(TestObj, Part, 1) wend a = a + (Old_x - objectnodex(TestObj, Part, 1)) * Old_y if a < 0.0 then rc = TRUE ' Clockwise end if IsClockwise = rc end function -----Original Message----- From: Mustafa VZGET]N [mailto:[EMAIL PROTECTED] Sent: 23 November 2004 16:39 To: [EMAIL PROTECTED] Subject: MI-L Polyline direction ??? Hi all. I have 2 questions: First, In MapInfo there is a polyline direction (in the object's drawing direction). Can we programmatically (ie via Mapbasic) obtain this direction (as clockwise or counter-clockwise)? Secondly, my actual purpose is: I have a parcel and I want to put a house in that parcel so that 1) The 3 walls of the house will be 4 meters inside (and parallel to) the 3 parcel sides. 2) The area of the house will be 70% of the parcel's area. (In this way the house will be closed up with the 4th side.) The shape of the parcel may be rectangle, trapezoid or more complicated. I need a strong and general algorithm which will work with even bad parcel shapes. I have found it difficult to decide which of the 2 parallel lines belong to the inner part of the parcel. (There are 2 identical lines which are 4-meters equidistant from a line.) Anyone suggest an algorithm or point me in the right direction? Thanks... --------------------------------- Do you Yahoo!? Meet the all-new My Yahoo! - Try it today! --------------------------------------------------------------------- List hosting provided by Directions Magazine | www.directionsmag.com | To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] Message number: 14225
