Dan,
If you open your mapbasic window (Options Show Mapbasic window) and type:
Set Area Units "hectare" then enter, it will alter the system area units.
r
On Wed, 17 Nov 2004 15:53:03 +1100, Dan Bowles <[EMAIL PROTECTED]> wrote:
Hi Soren
You sent me this email some time ago on area and proportionoverlap commands,
at the time I used other means, however, I'm now using areaoverlap to
calculate areas of lots affected by flood constraints. It's working quite
beautifully, however, I'm struggling with the area units. Changing the map
units from the Map>Options menu item does not seem to change the output
units. Is there some way I can modify the command to set units to "hectare"?
You're help is greatly appreciated.
Regards Dan Bowles BSc GIS Officer Harper Somers O'Sullivan
PO Box 428 HAMILTON NSW 2303
E [EMAIL PROTECTED] <mailto:[EMAIL PROTECTED]> T 02 4961 6500 M 04 3834 8372
-----Original Message----- From: S�ren Breddam [mailto:[EMAIL PROTECTED] Sent: Thursday, 12 August 2004 5:13 PM To: 'Dan Bowles' Subject: SV: MI-L FW: Determining polygon areas and proportions within polygons
Hi Dan, You do have options doing this with SQL:
MB help: AreaOverlap( ) funtion: Purpose
Returns the area resulting from the overlap of two closed objects.
Syntax: AreaOverlap ( object1, object2 ) object1 and object2 are closed objects.
Return Value
A Float value representing the area (in MapBasic's current area units - use
Set Area Units... to change this) of the overlap of the two objects.
Example:
Select AreaOverlap(PolygonTable1.Obj, PolygonTable2.Obj) , PolygonTable1.ID,
PolygonTable2.ID
Received: From PolygonTable1, PolygonTable2
Where PolygonTable1.Obj Intersects PolygonTable2.Obj
Into a Noselect
Browse * From a
ProportionOverlap( ) function:
Purpose
Returns a number that indicates what percentage of one object is covered by
another object.
Syntax ProportionOverlap(object1,object2) object1 is the bottom object (not text or points) object2 is the top object (not text or points)
Return Value A Float value equal to Area(Overlap(object1,object2) ) / Area(object1).
HTH S�ren Breddam
-----Oprindelig meddelelse----- Fra: Dan Bowles [mailto:[EMAIL PROTECTED] Sendt: 12. august 2004 02:14 Til: MapInfo-L Emne: MI-L FW: Determining polygon areas and proportions within polygons
Sorry, original message didn't work with explanatory attachment. Hope you understand without...
-----Original Message----- From: Dan Bowles [mailto:[EMAIL PROTECTED] Sent: Thursday, 12 August 2004 9:35 AM To: MapInfo-L Subject: Determining polygon areas and proportions within polygons
Hi all
I have a very large data set of vegetation classifications (various coloured
polygons in the base of the example map attached), in a GIS also including
proposed vegetation corridors (blue polygons), national parks (green
polygons) and state forests (brown polygons). The veg corridors, NPs and SFs
do not intersect, however, the vegetation classification polygons intersect
across all other layers.
I need to determine how much area there is of each vegetation class in total
and how much area of each class is contained within each of a number of
distinct veg corridors (blue), and generally within NPs (green) and SFs
(brown). I also need to determine percentages of each veg class within NPs,
SFs and veg corridors compared to the entire area.
I am having trouble getting MapInfo to automatically generate these statistics for me, any advice you could give would be fantastic.
Thanks for your help
Dan Bowles
-- ________________________________________________
Robert Crossley
Agtrix P/L 9 Short St PO Box 63 New Brighton 2483 Far Southern Queensland AUSTRALIA
153.549004 E 28.517344 S
P: 02 6680 1309 F: New Connection M: 0419 718 642 E: [EMAIL PROTECTED] W: www.agtrix.com W: www.wotzhere.com
--------------------------------------------------------------------- List hosting provided by Directions Magazine | www.directionsmag.com | To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] Message number: 14085
