A method of routing a sensor platform along a path to observe a region of interest and avoid obstacles within the region of interest, said sensor platform having a sensor that projects a constant sensor footprint to the surface, the method comprising: defining a rectangular bounding region around the region of interest; the method characterised by defining a convex polygon hull around an obstacle within the region of interest; generating a parallel arrangement of rectangular planks from each edge of the convex hull out to the bounding region, the extent of each said rectangular plank bounded at one end by the intersection of the plank with the bounding region and at the other end by the intersection of the plank with an extension of a next edge of the convex hull, wherein the parallel arrangement of rectangular planks is generated by drawing lines parallel to the edge of the convex hull spaced at at most the width of the constant sensor footprint until the last line is entirely outside the bounding region, intersecting the parallel lines with the bounding region, extending the next edge of the convex hull to the bounding region and intersecting the parallel lines with the extended next edge; routing a path to traverse the parallel arrangement of rectangular planks for each edge of the convex hull in a raster scan pattern and to circle the convex hull in a clockwise or counter-clockwise direction, wherein path segments that connect one plank to the next within each raster scan and connect the last plank of an edge to the first plank of the next edge comprise straight-line segments and arcs of a constant turn radius; and tracking the path and sensing the surface below to capture a sequence of sensor outputs that together cover the entire region of interest except the region excluded by the convex hull. defining a rectangular bounding region around the region of interest; the method characterised by defining a convex polygon hull around an obstacle within the region of interest; generating a parallel arrangement of rectangular planks from each edge of the convex hull out to the bounding region, the extent of each said rectangular plank bounded at one end by the intersection of the plank with the bounding region and at the other end by the intersection of the plank with an extension of a next edge of the convex hull, wherein the parallel arrangement of rectangular planks is generated by drawing lines parallel to the edge of the convex hull spaced at at most the width of the constant sensor footprint until the last line is entirely outside the bounding region, intersecting the parallel lines with the bounding region, extending the next edge of the convex hull to the bounding region and intersecting the parallel lines with the extended next edge; routing a path to traverse the parallel arrangement of rectangular planks for each edge of the convex hull in a raster scan pattern and to circle the convex hull in a clockwise or counter-clockwise direction, wherein path segments that connect one plank to the next within each raster scan and connect the last plank of an edge to the first plank of the next edge comprise straight-line segments and arcs of a constant turn radius; and tracking the path and sensing the surface below to capture a sequence of sensor outputs that together cover the entire region of interest except the region excluded by the convex hull.