Hi Peter, You would not need to use the "Select * From s_Layer Where OBJ Into EXISTING__OBJ NoSelect" query as your second statement will only return records that have objects associated with them therefore making the above clause redundant.
Cheers Martin -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]] Sent: Friday, 02 August 2002 18:22 To: [EMAIL PROTECTED] Cc: [EMAIL PROTECTED] Subject: RE: MI-L MB - Select with object variables Hi Peter, Here is my version of your IsLayerVisible() **************************************************************************** ********* Function LayerIsVisible(ByVal WinID as integer, ByVal s_Layer as string) as logical Dim Mx1, Mx2, My1, My2 as float, o_Rectangle as object LayerIsVisible = FALSE '**I have added the Set Coordsys syntax Set CoordSys Window WinID Mx1 = MapperInfo(WinID, MAPPER_INFO_MINX) My1 = MapperInfo(WinID, MAPPER_INFO_MINY) Mx2 = MapperInfo(WinID, MAPPER_INFO_MAXX) My2 = MapperInfo(WinID, MAPPER_INFO_MAXY) Create Rect Into Variable o_Rectangle (Mx1, My1) (Mx2, My2) '**If you are not sure whether you might have records without '**objects you might be interested in starting with this SQL Select * From s_Layer Where OBJ Into EXISTING__OBJ NoSelect '**If you use the SQL above change the s_Layer to EXISTING__OBJ '**Selection objects from current layers within current vindow area Select * From s_Layer Where OBJ Intersects o_Rectangle Into VISIBLE__OBJ NoSelect If TableInfo("VISIBLE__OBJ", TAB_INFO_NROWS) > 0 then LayerIsVisible = TRUE end if End Function **************************************************************************** ********* You might also move the extraction of the coordinates and the creation of your o_Rectangle on level up, so that you only have to create this object once for every Map window. You can then send the object to the LayerIsVisible procedure as a parameter in stead of the window id. HTH, Peter ---------------------------------------------------------------------------- -------------------- Peter Horsb�ll M�ller, GIS Udviklingskonsulent / GIS-Developer Kampsax A/S - GIS Software & Solutions Rugaardsvej 55, 5000 Odense, DK tel: +45 6313 5013, dir:+45 6313 5008, fax: +45 6313 5090 mailto:[EMAIL PROTECTED] www.kampsax-gis.dk and www.kampsax.dk Authorized MapInfo Partner & Distributor in Denmark and Norway. ---------------------------------------------------------------------------- -------------------- Se mere om Dansk MapInfo Brugerkonference p� http://www.kampsax-gis.dk/Default.asp?ID=296 Klik ind p� http://www.kortal.dk og se det hele lidt fra oven! Check http://www.kortal.dk and have a look at Denmark from above! ----- Videresendt af Peter M�ller/Kampsax - 02-08-2002 08:11 ----- "Peter Zyczynski" Til: <[EMAIL PROTECTED]> <peterz@insightg cc: is.com.au> Vedr.: MI-L MB - Select with object variables 02-08-2002 03:52 Besvar venligst til peterz Hi all, I'm after some ideas. I have about 40 tables of bus routes open in a single mapper window, some are within view, some are not. Out of the 40 layers I need to determine which ones are actually visible in the current mapper. Any ideas greatly appreciated. MY ATTEMPT: ------------ I was thinking of creating a rectangle the size of the mapper window into an object variable, and then running a query to see if my table intersects the object variable - but it don't work - I don't even get an error message! Reason for using an object variable was to optimise speed - I'm gona be evaluating a lot of workspaces with a lot layers. Here's the failed attempt code: -------------------------------- Declare Sub Main Declare Function LayerIsVisible ( ByVal WinID as integer, ByVal s_Layer as string ) as logical -------------------------------- Sub Main Dim i, WinID as integer, s_Layer as string Print chr$(12) WinID = FrontWindow() for i = 1 to MapperInfo(WinID, MAPPER_INFO_LAYERS) s_Layer = LayerInfo(WinID, i, LAYER_INFO_NAME) If LayerIsVisible(WinID, s_Layer) then Print s_Layer End if next End Sub -------------------------------- Function LayerIsVisible( ByVal WinID as integer, ByVal s_Layer as string ) as logical Dim Mx1, Mx2, My1, My2 as float, o_Rectangle as object LayerIsVisible = FALSE Mx1 = MapperInfo(WinID, MAPPER_INFO_MINX) My1 = MapperInfo(WinID, MAPPER_INFO_MINY) Mx2 = MapperInfo(WinID, MAPPER_INFO_MAXX) My2 = MapperInfo(WinID, MAPPER_INFO_MAXY) Create Rect Into Variable o_Rectangle (Mx1, My1) (Mx2, My2) '*** The following bit must be wrong because '*** it never evaluates to true. If s_Layer intersects o_Rectangle then LayerIsVisible = TRUE end if End Function -------------------------------- Peter Zyczynski Analyst Programmer Insight GIS Australia Ph: (03) 6244-7344 Fax: (03) 6244-7028 [EMAIL PROTECTED] www.insightgis.com.au --------------------------------------------------------------------- List hosting provided by Directions Magazine | www.directionsmag.com | To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] Message number: 2331 --------------------------------------------------------------------- List hosting provided by Directions Magazine | www.directionsmag.com | To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] Message number: 2336 Note: This message is for the named person's use only. It may contain confidential, proprietary or legally privileged information. No confidentiality or privilege is waived or lost by any mistransmission. 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