Expected gain: improve genericism in processing framework; removes a barrier in processing reduced res imagery.
Exchanges round for ceiling in determining a pixel buffer.
Reasoning: Requesting a buffer implies that edge information is required to compute a correct result, therefore we should ensure that we have enough data available for a computation
Impact: We were failing to create a buffer to calculate slope where pixels were greater than (1/2 * buffer_distance (currently 8000(m))).
Updated the dimension calculation for the slope subset to be more defensive by avoiding negative indexing on python array slicing.
Expected gain: improve genericism in processing framework; removes a barrier in processing reduced res imagery.