RasterControlPointList point ordering

[hannah]

Hello,

I am trying to create a warped rectangle similar to the RubberSheetImage example, using ImageUtil.warpImageWithControlPoints. I have four control points (the geographic location of the corners of my raster), and I am currently adding them to the RasterControlPointList in the order (lower left, lower right, upper right, upper left). I noticed that some of my SurfaceImages look rotated the wrong way (and/or flipped, I can't really tell yet). If I change the order I add control points, they are rotated differently (some correct, some not). It seems odd that it should matter since when a ControlPoint is created, you are giving it the raster (x,y) at the same time as the world (x,y), so why would it put the raster (x,y) at the wrong world (x,y)? Is it using a different raster coordinate system than the upper left being (0,0)? And is there a particular order that control points need to be added to the list?

Thanks for the help,

Hannah