Hello Listers, I wanted to thank Lars V. Nielsen, Martin Higham and Jaromir Svasta for all their help. I was able to find data that we had available with a more concentrated point for water depths. And was able to use suggestions from the before mention to calculate the min, max and mean. Thank you much, Rick A summary follows: Hello Listers, I have point data that has water depth values. I created a thematic map from these points. I have polygons that I would like to populate with the values of max, min and medium of what is from the thematic map for each enclosed polygons. Is there any way to do this? Thanks in advance, Rick ---Lar's Suggestion-------------------------------- Hi Rick, First you add an id to all point layer records depending on which polygon each belong to. This id must be unique, and can be added to the polygon layer using ROWID if necessary. It's transferred to the point layer table by a join that specifies point.OBJ within polygon.OBJ. You then issue a select statement on the point layer table, querying for Min(depth), Max(depth) and Avg(depth), grouping the result by the polygon id. This result can be transferred back to the polygon layer by joining on the polygon id. You probably have to save and re-open the grouped query first, but then it'll work. Best regards/Med venlig hilsen Lars V. Nielsen GisPro, Denmark http://www.gispro.dk/ http://www.gispro.biz/ ---My addition questioin----------------------------- Hello Lars, Thank you for you suggestion. I'll have to try it. But there is another problem I would have. The points are to disperse. Where at the thematic map interpolates from the point data to get a more accurate depth reading. Is there a way where I can create a more concentrated points and have the value for that point at that location populated with what the thematic layer reads/interpolates as the depth value? Thank you much, Rick ---Lar's second reply--------------------------------- Hi Rick, To generate additional points based on some sort of model, you will have to use some form of grid/3D program such as Vertical Mapper or Grid Analyzer. After you've created a more dense grid, you can still use the previously suggested method to calculate min/max/average per defined polygon. The utilities mentioned above may even have tools for it. HTH Best regards / Med venlig hilsen Lars V. Nielsen Hvenegaard & Meklenborg Rugaardsvej 55, DK-5000 Odense C Denmark http://www.hvm.dk ---Martin's suggestion---------------------------------- Hi, A bit easier than Lars's suggestion is to use Table > Update Column. Table to update is the polygon table, Get value from table is the points table.Join condition is geographic, where polygons contain points Expression is minimum(depth) or maximum(depth) or avg(depth) If you have the MapBasic window open when you do this, you will see the syntax that is used (which may make it easier if you want to do multiple updates, as the menu command only allows one variable at a time). Best Regards, Martin Higham Avantra Geosystems ph (61 3) 8504 0428 0425-730-428 fx (61 3) 9596 7997 www.avantra.com.au ---Jaromir's suggestion------------------------------------ Try this two statements (assuming your point table has numerical field "join_field", and you replace table/field names with the real ones): 1st step: Add Column "point_table" (join_field) From polygon_table Set To RowID Where Contains 2nd step: Select max(the_field),min(the_field),avg(the_field) From point_table Group By join_field Regards Jaromir Svasta ---Jaromir's second reply------------------------------------ Sorry, I haven't read this before I sent you my last suggestion. I am afraid there is not a straightforward solution in MapInfo alone to get interpolated values into your polygons. You must use one of MapInfo add-ons like Grid Analyser or Vertical Mapper which both have point and region inspection functions. I would prefer Grid Analyser (www.terris.com) as it is directly working with MapInfo thematic grids (and is cheaper). Jaromir Savsta --------------------------------------------------------------------- List hosting provided by Directions Magazine | www.directionsmag.com | To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] Message number: 8758
