Responsible for making topographic maps and other maps ??? ??? ??? 7.5 minute quadrangle USGS map series ??? ??? ??? gradient slope or how steep the land is ??? ??? ??? level land shown by contour lines far apart ??? ??? ??? steep land shown by contour lines close together ??? ??? ??? profile shows elevation changes across a map section ??? ??? ??? remote sensing methods include Landsat and imagin