mapbasic update a column with centroid of object

Question

I have a table that has a few polygons. I would like to extract the centroid of each polygon and fill up the columns named, Cent_X, and Cent_Y.

The syntax for getting the centroid is CentroidX(obj) and CentroidY(obj). A statement like this doesn't work:

    Update TableA
        Set Cent_X = CentroidX(Obj)

Can anyone please help?

Answer 1

Before Update statement set coordinate system first:

Set CoordSys <some coordinate system specification>

And field type for the column Cent_X should be Float.

Also, check if TableA has some records without object (if this is the case then your statement should throw an error, but you did not said what is exactly the problem):

select * from TableA where not Obj into Selection
browse * from Selection