I am developing a Visual Basic application to display legal descriptions of airspace boundaries in MapInfo. The user will be able to enter the description in the VB application, and the application will output the MIF/MID files for the entered description.
I have no trouble writing the straight line (polyline) features, but I am having some trouble understanding how arcs are specified in the MIF. The documentation regarding this in the MapInfo manual is rather brief and doesn�t include a diagram. Does anyone have any better documentation or, perhaps, a diagram or example of how to compute the required arc parameters? The boundary descriptions, that the user will enter, define the arcs by starting and ending points and a radius from a given centre point, with all the points being in geographic coordinates (latitude/longitude, GRS80). I think I will have to project these points onto a mapping plane, then do the calculations to get the required MIF parameters, then convert the projected coordinates of the MIF arc parameters back to geographic coordinates to be written to the MIF. Is the correct approach? This is a sample airspace boundary description: The airspace from 700� AGL to FL 230 within the area bounded by a line beginning at: N49�15'21" W124�29'35" to N49�18'59" W124�18'55" to N49�25'12" W124�00'26" thence clockwise along the arc of a circle of 35 miles radius centred on N49�11'42" W123�10'55" Vancouver Intl, BC ARP \ to N49�29'04" W123�57'39" to N49�45'15" W124�19'32" to N49�53'24" W124�05'05" thence counter-clockwise along the arc of a circle of 35 miles radius centred on N49�45'14" W124�57'29" Comox, BC NDB \ to N49�15'21" W124�29'35" point of beginning. Any help, comments, or suggestions are appreciated! ______________________________________________________________________ Web-hosting solutions for home and business! http://website.yahoo.ca _______________________________________________________________________ List hosting provided by Directions Magazine | www.directionsmag.com | To unsubscribe, send e-mail to [EMAIL PROTECTED] and put "unsubscribe MapInfo-L" in the message body.
