--Boundary_(ID_u6BE+Wc+5vbHWqAhP+duCA)
Greetings, List. There isn't much to summarize, I'm afraid. David Haycraft [EMAIL PROTECTED] offered software that he had developed. I won't be using this solution because my customer's demands have been relaxed - I no longer need to return a house number. This simplifies the problem to an almost triviality. David's description (following) seems to answer the bill. A screenshot was attached for clarification, but I cannot append it here. Anyone interested may contact David directly. I have developed a more-or-less-industrial-strength MapBasic program called Loc2Add.MBX that performs reverse geocoding on a table of point symbols. Specifically, for a table of points with (empty) Street and Region columns Loc2Add finds the nearest street address and region ID of each point and updates fields Street and Region. Loc2Add requires a non-view StreetInfo file and a Boundary file for the neighborhood enclosing the points. I have used Loc2Add successfully for two applications: 1. to get street addresses for all Australian Schools that appear in MapInfo Australia's Streetworks "cultural features" dataset 2. to generate a file of pseudo-random street addresses for use in comparative testing of MapInfo Australia's MapMarker and Geooc geocoding engines. For each point to be processed Loc2Add searches in an expanding circular region centered on the point for the centroids of StreetInfo-format line segments until it gets a non-empty result set. Then for each candidate line segment, it calculates the (cartesian) perpendicular distance to the line, and selects the closest line. It then figures out the block number by linear interpolation , and retrieves the name of the boundary and add updates the point table row. Attached is a screen-shot of reverse geocoding my office location (the Blue dot) with debugging code enabled in Loc2Add to show the perpendicular distances calculated in deriving my address. Be aware that, at least in Australia, street addresses are NOT always derived the closest point on the closest road. The main variation is for corner blocks, where the practice is usually to chose the shortest side as the "frontage". The other problem, particularly severe with large properties like schools, is that the site may well be bounded on all sides by public roads, so programs like Loc2Add, while yielding valid addresses, generate stuff that nobody recognizes. ...SNIP... Regards David M Haycraft Information Analysis Associates Pty Ltd ABN 47 085 516 105 1 Cumming Place, Wanniassa, 2903 Aust Capital Territory, Australia Phone/Fax: 61 + 2 + 6231 8104 Mobile: 0412 001 134 Email: [EMAIL PROTECTED] Web : www.acslink.aone.net.au/actaa/iaa.htm A MapInfo Technology Partner ----- Original Message ----- From: "Alex Eshed" <[EMAIL PROTECTED]> To: "MapInfo-L" <[EMAIL PROTECTED]> Sent: Tuesday, 18 December 2001 01:00 Subject: MI-L Reverse Geocoding > > --Boundary_(ID_iQ34m86ry9MpwgJXzrj2cw) > > Greetings, List. > > Does anyone have a coded (MapX or MapBasic) solution for Reverse Geocoding? > > Problem definition - input is a pair of coordinates (from table or keying > in), output is the closest (within a specified tolerance) street name and > house number. Actually, no map display is necessary. > > TIA to all responders. Will summarize responses, if any. Alex Eshed --Boundary_(ID_u6BE+Wc+5vbHWqAhP+duCA) _______________________________________________________________________ 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.
