Hello, I need some suggestions on navigating an image in IDL - kind of transformation of pixel coordinates in byte arrays to Actual planetary coordinates - In other words, Georeferencing. I'm working on Image Navigation of telescopic Venus data at 0.21 rcseconds perpixel. I have to do my Image Navigation in IDL. The images I have are rotated clockwise 145 degree to make it vertical. I could get the North pole position angle and North pole position distance from JPL Horizon website. I can also get the sub observer latitude and longitude.I also have the centre pixel coordinates of venus disc. How can I go about making a grid for venus? How can i navigate the image such that each pixel shows venus planetocentric coordinates like polar regions have 90, equator zero etc. I understand that I need to mark the pole coordinates by the above mentioned data and then interpolate it for other pixels. But, Im not sure how to proceed. Thank you in advance, Aishwarya.