A New Approach for Applying Bathymetry to Nautical Charts Noel Dyer Cartographer, NOAA

Current Electronic Chart Suite

Re-scheme Plan

Reducing ENC Scales Reducing unique scales from 131 to 10 Re-compilation of data to fit new scales Applying new incoming data directly to the updated scale

Recommended depth contours per scale band Standard Scale (rounded) Width Height Band 1 1:5,120,000 38.4 100, 200,… 1:2,560,000 19.2 50,100,150,200,… Band 2 1:1,280,000 9.6 1:640,000 4.8 20 ,50,100,150,200,… Band 3 1:320,000 2.4 20,30,50,100,150,200,… 1:160,000 1.2 10, ,20,30,50,100,150,200,… Band 4 1:80,000 0.6 5, 10, ,20,30,50,100,150,200,… 1:40,000 0.3 2, 5, 10, ,20,30,50,100,150,200,… Band 5 1:20,000 0.15 2, 5, 8,10,15,20,30,50,100,150,200,… 1:10,000 0.075 2,3,4,5,6,7,8,10,15,20,30,50,100,150,200,… Recommended depth contours per scale band IHO S-4 (B-411)

Hydrographic Survey Data MCD receives survey data in grid format Cleaned for anomalies, set to horizontal/vertical datum prior to arrival Sunset of H-Cell (USGS)

Bathymetric Attributed Grid Depth Uncertainty

Automating Cartographic Processing Tool developed to support the creation of new re- schemed ENC chart products Creates depth areas, contours and soundings at scale from input raster surface (BAG file)

Simplified Workflow Creates depth areas through series of geo-processing tasks Raster to polygon, dissolve, buffer, aggregate, smooth, clip Creates contours using the intersections of adjacent depth areas Creates soundings by converting the input raster to point features Also creates a thinned version for display purposes

Automating Cartographic Processing Depth Range

Another Example

Limitations Depth Range

Conclusions Tool developed to derive depth areas, contours, and selected soundings from gridded bathymetry data Positive feedback from MCD cartographers Efficiency and support for cartographic judgements May still require manual adjustments Improvements in development

Thank you for your time! Questions?