Good morning all, I ran Mark Ogilvie's mbx demonstrating problems with the area calculations in MI. As a test, I constructed some smaller triangles by overlay at the top vertex, and found that these also had large differences in areas. As a second test, I constructed a small circle (radius 4.565 km as it turned out)in the same window and projection, drew a horizontal chord through the bottom, and projected a radius vertically down from the centre. I set the y coords of the chord to be identical, and the x coords of the radius to be identical to ensure horizontal and vertical lines respectively. From the circle centre and three points on the circumference of the circle I was able to draw matching triangles, ... whose areas calculated to be the same. Also the area of the combined triangles was twice that of the separate ones. I can only suggest that there is something odd in the way that MI handles the means Mark used to construct his triangles. Cheers Mal Mal Jones Cooperative Research Centre for Landscape Evolution & Mineral Exploration Queensland Centre for Advanced Technologies PO Box 883 Kenmore Queensland Australia 4069 Ph (07) 3212 4610 Fax (07) 3212 4455 Web: http://leme.anu.edu.au/ ---------------------------------------------------------------------- To unsubscribe from this list, send e-mail to [EMAIL PROTECTED] and put "unsubscribe MAPINFO-L" in the message body, or contact [EMAIL PROTECTED]
