Chart Tile Service to Aid Charts Update

  

Accessing up-to-date nautical charts on electronic systems and mobile apps is about to get easier, as developers start adopting NOAA Coast Survey's new Chart Tile Service prototype. Navigational chart users should not notice any difference in how their charting systems operate - except that service providers will be able to quickly update the charts with hundreds of corrections applied weekly by NOAA, so users will have the corrected versions faster than ever before.

"New generation navigation systems - chart plotters, tablets and mobile devices - and web mapping applications increasingly use tile services," said John Nyberg, chief of Coast Survey's Marine Chart Division. "By subdividing raster charts into more manageable tiles that upload much faster, this new service will give navigation system developers greater ability to provide official corrections to NOAA's nautical charts."

"To think of how systems use chart tiles, look at a bathroom wall," Nyberg explained. "A solid wall is made up of separate tiles. Now, you don't want to tear down the wall and build a whole new one when one tile is bad. You want to replace that single tile. It's the same with chart tiles."

The Chart Tile Service is comprised of 15 million individual tiles. Every week, Coast Survey identifies the tiles that have had an update, and sends those individual tiles. 

Until now, third-party commercial vendors had to create their own tile sets from NOAA raster navigational charts (NOAA RNC®) for use in their systems, but virtually "cutting up" NOAA charts into more usable tiles is costly, time consuming and produces inconsistent results among the different vendors' tile sets. This is because multiple charts may cover the same area at the same scale, and the vendor must choose one chart to populate each tile. As a result, the companies creating their own tiles usually only rebuild their tiles once or twice per year and customers using these commercial services don't have access to the most recent data.

NOAA updates its suite of more than a thousand digital charts weekly. The chart updates can include data from full hydrographic surveys and vector shoreline data, as well as Notice to Mariners corrections for dangers to navigation.

This Chart Tile Service prototype released in December is for online tiles, compatible with web mapping applications. Next up - scheduled for late spring 2016 - will be tile sets packaged for offline use, where all tiles at all scales within a geographic region will be packaged together. These tile packages can then be updated with weekly "delta" packages, containing only the tiles that have changed since the last full package. This will dramatically reduce the bandwidth requirements necessary to keep a vessel's chart suite up to date.