These are the steps you need to accomplish the conversion:

• Choose a floor plan image and take note of the pixel coordinates (pixels x; pixel y) of 3 or more points on it. Please choose points that are far from each other. We suggest to use the 4 corners of the floor plan image. The coordinates of the 4 corners are:
  • [0; 0]
  • [0; max image height]
  • [max image width; max image height]
  • [max image width; 0]
• Upload the floor plan image inside the Dragonfly dashboard by following these instructions.
• Once the floor plan has been uploaded inside the Dragonfly dashboard:
  • Select General from the top menu. Then select Floorplans.
  • Click on the floor plan of interest (not on the EDIT button!).
  • Zoom in as much as possible and move to the first corner of the floor plan image.
  • Click on the first corner and take note of the lat/lng fields:
    • E.g.: [0; 0] -> [45.610829, 9.351505]
  • Click on the other 3 corners and take note of the lat/lng fields.
• You have now all what you need to create a [4 x 4] matrix where each row contains the correspondence between pixel x/pixel y and latitude/longitude: [pixel_x pixel_y latitude longitude].
• Compute the transformation matrix using least squares approach.

Once you have the transformation matrix you can apply it to any pair of latitude/longitude coordinates to obtain the corresponding pair of x/y pixel of your floor plan image.