Hi all, I have a mapinfo table which consists of two joined databases. The first has postcode housing data with co-ordinate info mapped to the British National Grid, the other (also including data mapped to the British National Grid) contains data on pollution sites. The database is called jdb4.tab. I have also made a copy called jdb4.dbf. Over the past month I have successfully been able to create a variable called 'sitedistance' which gives the distance between a house and a pollution site (The original jdb4 database was created by creating 4 mile buffers aroundeach house and writing an sql command to join the database where ever pollution site objects fell within each house buffer object). The procedure I used to create the sitedistance column was: TABLE MAINTENANCE>TABLE STRUCTURE>JDB4.TAB>ADDFIELD (SITEDISTANCE -in decimals). Afterthe column had been created I used the following expression in UPDATE COLUMN : DISTANCE(EASTING, NORTHING, XCOORD, YCOORD,"mi") (Easting, Northing =pollution site co-ordinates, Xcoord, Ycoord = house site co-ordinates - all in the same joined table). The above command worked well for three different 10% housing samples created by joining the two databases to give jdb4.tab (1), jdb4.tab(2) and jb4.tab(3) in three separate file spaces. Now I have created a fourth file space and have tried to repeat the above procedure with another 10% housing sample but I get gibberish - the SITEDISTANCE column now always returns a value of 0 fore each record where I was expecting values representing site distance. The co-ordinates are also for each record which means that values other than 0 should be calculated for this field. Does anyone know what I might be doing wrong or if there is some technical hitch/bug that I am encountering? It is most bizarre that the procedure should work well for 3 repetitions and then fall down on the 4th. Incidentally another problem, a couple of times during the third attempt and also once during the fourth, while trying to create the sitedistance column I came up with the message: MAPINFO DOES NOT SUPPORT METADATA FOR JDB4.DBF my e-mail is: [EMAIL PROTECTED] Please reply asap, I would be very greatful. Thanks, Sam ---------------------------------------------------------------------- To unsubscribe from this list, send e-mail to [EMAIL PROTECTED] and put "unsubscribe MAPINFO-L" in the message body, or contact [EMAIL PROTECTED]
