So you want to make a planet from a photo that you like. Well there is a few things to consider.
First of all you need to take a photo with lots of interesting objects on the horizontal skyline. Try and get a perfectly straight horizon.
The next thing to do is to shoot in a square format, or use some software to transform the photo into a square format.
If you leave the photo the way that it has been shot then you will get all of the objects pointing in towards the centre.
So to get the buildings and trees pointing outwards you need to rotate the photo by 180 degrees so that it becomes upside down.
Being a cheapskate I have used GIMP to do the circular distortion. Under the Fliter option choose "distort" and then "polar cords".
You can then rotate the image to position the houses and trees in a way that you like them.
You can see a line where the ends have been joined and if you have time and the inclination you can dodge and burn the edge so that the join is seemless.
But hey who cares? www.ipernity.com/doc/hyperbob/album/42161