A method for decoding a picture from a bitstream. The picture comprising a number of units, and the picture being partitioned into a number of spatial segments by a partition structure. The method includes decoding one or more code words in the bitstream; determining that the partition structure is uniform based on the one or more code words; determining the number of spatial segments based on the one or more code words; determining a segment unit size; and deriving the sizes and/or locations for spatial segments in the picture from the one or more code words. Deriving the sizes and/or locations for spatial segments in the picture comprises a first loop over the number of spatial segments in a first dimension or direction. A number of remaining segment units in the first dimension or direction to be segmented is calculated inside the first loop.