I am not sure if I am following correctly. Why not take the average or sum the Japanese Wards. You would use SQL Select and for columns, the first should be the unique id of the Japanese wards. If you need more, add them in. The last column should be the census data, this is the one you will use the for the max value, sum, average; whichever you choose. Where clause will be the objects column for each table. It is very important which operator you use in the where clause. Contains will choose objects from the census data where the centroid falls within the JW polygon. Intersects will figure every census object that touches the JW polygon. Contains entire will only choose objects that are entirely within the JW polygon. Each one of these will yield a different result. My suggestion is try one way and spot check the results and see if that is what your looking for. If its not, change the operator and try again.
I don't know if this is what you were asking for. Hope it helps. Mike Hankins Actuarial Services Analyst COUNTRY Insurance and Financial Services 309-821-2302 -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Sent: Wednesday, June 09, 2004 9:30 AM To: [EMAIL PROTECTED] Subject: MI-L Population Weighted Centroid I have a 1km grid containing Industrial Census Data. I also have irregular polygons (Japanese Wards) that will normally contain many of the 1km grid squares. Does anybody know of a technique whereby I can derive a centroid of the ward based on the values of one of the attributes in the grid? The obvious would be to choose the centroid of the largest but I would rather not. Thanks Andy Disclosure of Material Facts Every Proposer or Insured / Reinsured when seeking new insurance / reinsurance or renewing an existing Policy must disclose any information which might influence the Insurer / Reinsurer in deciding whether or not to accept the risk, what the terms should be, or what premiums to charge. Failure to do so may render the insurance / reinsurance voidable from inception and enable the Insurer / Reinsurer to repudiate liability. This email, together with any attachments, is for the exclusive and confidential use of the addressee(s) and may contain legally privileged information. Any other distribution, use or reproduction without the sender's prior consent is unauthorised and strictly prohibited. If you have received this message in error, please notify the sender by email immediately and delete the message from your computer without making any copies. While attachments are virus checked, Aon Limited does not accept any liability in respect of any virus which is not detected. Aon Limited Company Number: 210725 Registered Address: 8 Devonshire Square, London, EC2M 4PL Aon Limited is a member of the General Insurance Standards Council (registration 2239) --------------------------------------------------------------------- List hosting provided by Directions Magazine | www.directionsmag.com | To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] Message number: 12096
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