Hi
I'm assuming you are using MapInfo Pro v2019 or newer.
You can create a SQL Select statement that creates these squares. The trick is to create a 45-degree line through the point by offsetting the points 60 meters to the south and east and 60 meters to the north and west. You then create a minimum bounding rectangle around this line, and end up with a square around the input point.
Let me show you this in two steps. First the 45-degree line:
I use the SQL window to run my query. I use the MapBasic function CreateLine() to create a line. This function takes two coordinate pair, the start and end point.
To calculate these points, I use the MapBasic function CartesianOffsetXY(). This function takes four parameters. The object to offset. The change in X and the change in Y, and finally the distance units for the change in X and Y.
To extract the coordinates from the moved point, I use the MapBasic functions CentroidX() and CentroidY() which return the X and Y coordinates for the centroid of an object, in this case, the point itself.
The Select statement looks like this. I have split it across multiple lines to make it easier to read.
Set Coordsys Table Incidents
Select i.*,
CreateLine(
CentroidX(CartesianOffsetXY(i.OBJ, -60, -60, "m")),
CentroidY(CartesianOffsetXY(i.OBJ, -60, -60, "m")),
CentroidX(CartesianOffsetXY(i.OBJ, 60, 60, "m")),
CentroidY(CartesianOffsetXY(i.OBJ, 60, 60, "m"))
) Object
From Incidents As "i"
Into Selection
You can see the result below on the map as the red lines go through the orange dots. Oh, and notice the Object keyword I use after the CreateLine() function. This tells MapInfo Pro to use the resulting object as the spatial object for the query. This only works in MapInfo Pro v2019 or newer.
That's more than half the job done. We only need to add a function that returns the MBR of the line instead of the line. The MapBasic function MBR() does this.
Set Coordsys Table Incidents
Select i.*,
MBR(
CreateLine(
CentroidX(CartesianOffsetXY(i.OBJ, -60, -60, "m")),
CentroidY(CartesianOffsetXY(i.OBJ, -60, -60, "m")),
CentroidX(CartesianOffsetXY(i.OBJ, 60, 60, "m")),
CentroidY(CartesianOffsetXY(i.OBJ, 60, 60, "m"))
)
) Object
From Incidents As "i"
Into Selection
Now you can save the result into a new table to maintain the squares.
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Peter Horsbøll Møller
Principal Presales Consultant | Distinguished Engineer
Precisely | Trust in Data
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Original Message:
Sent: 05-31-2023 07:11
From: Paulo M Carochas Nunes
Subject: Create square grids from points or rotate individual diamonds on their centroid
Hi, I am struggling to convert a list of over 2000 points into 120m squres. By buffering object I managed to convert them to diamonds, but i can't seem to be able to rotate those diamonds on their own centroid. So can anyone please let me know how to rotated individual polygons on their centroids or a way to create squares directly from points.
Thanks
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Paulo Nunes
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