User`s guide

R14SP2
21-2
New Function Reads Both 5-Minute and 2-Minute ETOPO Data
The new function etopo reads from either the 5-minute (ETOPO5) or the 2-minute
(ETOPO2) global terrain data set. This function supersedes function etopo5 and fixes
several significant bugs.
Function gshhs Now Returns a Version 2 Geostruct
Function gshhs, which reads the Global Self-consistent Hierarchical High-resolution
Shoreline data set, has been upgraded. It now returns a Version 2 geographic data
structure (geostruct2) array instead of a Version 1 geostruct. Polygons returned from
gshhs now follow the shapefile vertex-ordering convention (supported by functions
polybool, shaperead, and shapewrite, for example). Under this convention the
coordinates of outer rings (e.g., continent outlines) are given in clockwise order, while
counterclockwise ordering is used for inner rings (e.g., lakes and inland seas within a
continent). Note that function gshhs does not yet support Version 1.3 of the data set,
released on Sept. 27, 2004.
Geodata Can Now Be Exported in Shapefile Format
The new function shapewrite writes a geographic data structure to a shapefile. It
exports a Version 2 geographic data structure array (geostruct2), creating .shp, .shx,
and .dbf files. Like shaperead, the function supports the Point, MultiPoint, PolyLine,
and Polygon shape types. The contents of string-valued attribute fields and scalar
numerical attribute fields are written to the dBase (.dbf) file.
Accessing Geodata Resources on the Internet
Links and URLs to documentation and data files for various Internet sources of digital
map data are now collected in the following technical note on the MathWorks Web site:
http://www.mathworks.com/support/tech-notes/2100/2101.html
This technical note replaces many individual links formerly scattered across the User's
Guide, reference pages, and MATLAB function help. Collecting this information on a
Web page rather than on product CDs or printed documentation should substantially
mitigate recurrent problems with stale links. Please report any stale links that you might
find in the technical note to MathWorks Technical Support (http://www.mathworks.com/
contact_TS.html), so that it can be updated promptly.