# Powers of Two rules vs. RW terrain sizes

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Hey everybody:

Sorry, two new threads in a day might overload this here enterprise, but I'm hitting an annoying brick wall, and I have a question that NO tutorial has answered.

Does every single terrain have to perfectly match a power of two in size?

In tutorials involving real world terrain importing, people seem to sort of magically end up with a consistent 2048x2048 meter terrain- exactly one size for the tutorial, with no explanation of how they happened to perfectly get a 2048 meter square map out of, for instance, a 176km square island, without rescaling it and thus messing up the whole point of importing real world data.

Specifically for me, I'm trying to use a block of territory roughly 10.5 km square in size. Is TB so completely damn restrictive that I have to confine myself to either carving out a chunk of that at 8192m square or expanding to an uncomfortably sized 16.384 km square terrain?

In short, nothing I've seen explains the rules of numbers in TB in an adequate or half-complete way. I can size down a BIT if necessary, but I'm looking to use a very specific 10.5km area. How the hell do I get that to play ball, or am I literally stuck with chopping half of it off to make an 8km map or including extra garbage to make a 16km map?

By the way, if it's any use in recommendations, all my sat/mask/heightmap sizes are 2048 square in pixels.

Thank you all, I hope your answers can help me resolve some serious stress. I have no idea how to fix this without rescaling the map (which removes the entire purpose of me trying to do a real-world map)

Edited by spartancain

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You can get a 10.5km x 10.5km map by having a heightmap that is 2048px x 2048px with a cell size of 6m. That will actually give you a 12.288km x 12.288km. You could also do a 1024px x 1024px with a cell size of 12 to get that same size. Or you could drop it down to 11 to get 11.264km. I would recommend using the 6m one though. You can also use decimal ones so a 2048px x 2048px with a 5.12m would give you 10.485km. I try to stick to full numbers even though they aren't required. Generally speaking you want your sat and mask to be 1m/px for your heightmap. That means if you have a 10.5km x 10.5km terrain you want a 10500px x 10500px image for your satellite and mask.

Programs that might help you get the exact size you want include MicroDEM, Global Mapper, and QGIS.