NOAA is showing steady progress toward reducing the backlog of square nautical miles (SNM) in critical need of being surveyed, determined by the age of the most recent survey, the nature of the cargo (hazardous materials, people, etc.) traversing the area and the degree of shoreline change since the most recent survey. Updated charts reduce the potential for groundings and therefore make ocean traffic safer. It is also clear, though, that progress in meeting this measure is slow and will take many more years of effort.
NOAA measures its performance according to the percentage of charts available in raster (picture image) format and vector (data) format. As of 1997, all charts are available in raster form; while vector charts are in the process of being developed. This will provide mariners with the accurate, up-to-date, electronic chart data needed to safely and efficiently navigate waterways using today's computer and positioning technology.