Search for Maryland GIS data. A GIS data search can provide information on GIS maps, property lines, county lines, city lines, public property, elevations, flood zones, school boundaries, earthquake zones, property appraisal values, erosion, water pollutants, topography, soil composition, sewers, public utilities, building hazards, population information, demographic information, place names, public property, parks, campgrounds, trails, trail maps, historic maps, historic GIS maps, town maps, county maps, city maps, and neighborhood boundaries.