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Detailed Coastlines and Borders

Questions:

I need better resolution for coastlines on my plots.

I would like to display state and country political boundaries on my plots.

Example:

Hawaii detail	Australia with borders

Solution:

(First, try Ferret's land_detail script, which uses data from the GMT (Generic Mapping Tools) site at http://gmt.soest.hawaii.edu (the GMT intermediate level of resolution). A demo of land_detail.jnl is at http://www.ferret.noaa.gov/Ferret/Demos/land_detail/land_detail_demo.html)

The USGS has a Coastline Extractor server: http://www.ngdc.noaa.gov/mgg/shorelines/shorelines.html which makes available for download coastline, boundary, and river segments with a choice of resolutions. Thanks to Patrick Brockmann and Carla Moore for alerting us to this resource!

Proceed as follows:

• Get coastline/border data from the Coastline Extractor
  • Select the database you want.
  • Select Mapgen as Coast Format Options
  • Submit your request
  • Save the data file
• Fix up the file for Ferret
  • With your favorite editor, change all:
    # -b   to   -1E+34  -1E+34
• Note the number of lines
  • wc -l  filename
• With Ferret:
  • DEFINE AXIS/Z=1:number_of_lines:1 vector_length
  • DEFINE GRID/Z=vector_length vector_grid
  • FILE/VAR=lon,lat/G=vector_grid filename
  • PLOT/VS/LINE lon,lat
• Add rivers or/and political boundaries from other files. Political boundaries aren't necessarily up to date, but it may be possible for you to locate by latitude and longitude any segments you want to remove from the data file.

Example script:

Note that the longitudes are returned as East longitude. Here we specify longitude to Ferret as a West longitude, so we need to plot (360+lon)

    !  Overlay detailed map of Hawaii on a vector plot.   

    USE coads
    SET REGION/X=165w:150w/Y=15:25/T="15-FEB-1993"
    VECTOR/title=""/nolabel uwnd,vwnd

    DEFINE AXIS/Z=1:11613:1 vec_len
    DEFINE GRID/Z=vec_len vec_grid
    FILE/VAR=lon,lat/G=vec_grid hawaii.dat
    PLOT/VS/LINE/OVER/COLOR=BLUE/NOLABEL 360+lon,lat

The map of Australia above was made with the WCL data (lowest resolution) and internal boundaries from WDBII.