About this map:
This map shows the mean stream gradient (in degrees) for each stream segment (defined as section of a stream stretching between any two adjacent confluences with other streams). The value assigned to each segment is the average of gradients across the segment's entire length, so the longer a segment, the less representation of small variations in gradient (a long segment, for example, can have low gradient overall but still contain steep sections). The values were derived by means of GIS spatial analysis techniques using the slope raster and river dataset as inputs. This dataset was created by Island Research & Education Initiative for the purposes of this atlas.