Image georeferencing, pixel projection is not correct

MapWinGIS
1

Hello, Everyone, please help!

I have a blueprint jpg image with world file and *.prj file, and intend to draw some dots in the blueprint base on pixel coordinate. When I loaded the blueprint using Image.Open(), I got the display shown as attached screenshot.

The functions I can find out are
Image.ImageToProjection(int Column, int Row, out double ProjX, out double ProjY)
Image.BufferToProjection(int BufferX, int BufferY, out double projX, out double projY)
and used them to project the dots. Apparently that is not what I expected. All the dots shall be drawn within the white blueprint and the whole things shall tilt as the white blueprint. Look like those functions did not take the pixel coordinate as the blueprint’s coordinate.

So, is there any solution?
Any help, any idea? All will be very much appreciated.

Peter

image
image568×617 124 KB

2

In case someone encounters the same problem. here is the solution

transform the pixl xy per equation

1 Like
3

Glad you found a resolution. Are you saying that you had to modify the World file?

4

No, read the 6 coefficients from world file and apply to the equations
x1 = Ax + By + C
y1 = Dx + Ey + F
then, pixel coordinate (x,y) => world coordinate (x1, y1)