# Thread: Cartesian to polar of conversion

1. ## Cartesian to polar of conversion

Hi

I am a trying to determine an objects position on a polar diagram, given its position on a cartesian plane. The object has length , width and orientation. The orientation will obviously determine the size of the object as seen from the origin of the polar plot

I want to determine its position on a polar plane (r theta). This is easy if the object is a point but if it has extent (i.e length and width) then the angle it subtends on the polar plot will be different depending on its orientation.

Any ideas on how to determine the angle subtended by an object on a polar plot of such an object , or maybe point me in the correct direction

Regards

2. Find the center of the object and refer everything to that point. That is the simplest way. Alternatively you could find the coordinates of specific points on the object and hence have a number of polar coordinates for different points which then discribes the orientation and position of the object ( there are a number of ways to do this)

3. Thanks,

I know the centre of mass of the object, e.g x,y is 500,500.

I dont know how to find the extents of the object. For example if the object is orientated at say 135 degrees wrt the centre of mass and has a length of 100 and width of 20, how would I do this?

Thank You for your time

4. Do you have the diemensions of the object? What sort of shape is it?

5. Yes

It is 100 units in length and 20 units width (it is a rectangle), with an orientation about its centre of mass of 135 degrees, measured clockwise from the Y axis, i.e pointing south east

Thanks

6. Work ot the the coordinates of the points of the corners, differences in these coordinates will give you all the information you need.

I'll leave to work out how for now...