Hi Arash A thematic map will be slower than a non thematic map, because when MapInfo has pulled the object out of the map file, it then has to go off to the DAT file to get the data values before it can work out the colour/style.
Stored with the object in the MAP file is its record number. So the answer to your question is:- WITH DAT Having got the record number from the MAP file, MapInfo can go straight to the field value that you are mapping on because each record and each field are fixed length in the DAT file ( and also in DBF). WITH CSV With your ascii file neither the fields or the records are fixed length. Therefore it has got to work its way through the file, or build a set of pointers to records. Having done this it has still got to work throught the record to get to the appropriate comma and data value. Repeated over and over again this leads to your time difference. Regards Bob In message <3F81103873E37E418FBA63F5CFFAEDCDB5A52F@gxymail>, Vakili, Arash <[EMAIL PROTECTED]> writes >This may not be such an exciting discovery, but I recently noticed how the >speed of creating a thematic layer increases when the table that is being >worked on is a "Native" (I imported a MID/MIF) vs. "ASCII" (I created the >table from a comma delimited text file). I would think once the .tab and >respective files are created, MapInfo wouldn't care what format the data >really came from (although it obviously does since it notes that in the .tab >file). > >Am I making a simple mistake or this actually make sense? > >And if this is really the case, why wouldn't MapInfo just use the MID/MIF >concept as a intermediate step before creating the .tab ( which is what I >do with integrated mapping)? Seems to be it would be very beneficial? > >Anyway, not a big deal but I found it interesting.... > >Arash > > > >_______________________________________________________________________ >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. -- Bob Young - www.bydesignwales.demon.co.uk _______________________________________________________________________ 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.
