[GRASS-user] r.thin ?

[charlie]

Hamish, you are correct, it is Hempstead Bay, I have downloaded the most current vector map from NYS.  The raster map I am looking to convert is not a recent map, but from 1929. 

Thanks for the tip on the  S-57 driver, it is not something that I was aware of.

--- On Wed, 11/10/10, Hamish <hamish_b at yahoo.com> wrote:

From: Hamish <hamish_b at yahoo.com>
Subject: Re: [GRASS-user] r.thin ?
To: "charlie" <carowan at yahoo.com>
Cc: "GRASS user list" <grass-user at lists.osgeo.org>
Date: Wednesday, November 10, 2010, 6:02 AM

charlie wrote:
> In response to your questions, I am trying to convert a raster
> map (a scanned & georeferenced map with only XY data)
> with a shoreline and some wetland islands into a vector map
> so I can compare gains/losses over time.
>
> A preview of the map is here: http://historicalcharts.noaa.gov/tiled_jpgs_done/zoomifyURLDrivenWebPage.htm?zoomifyImagePath=579-12-1929

if I am getting that right, the area is Hempsted Bay?
if so fyi NY DEC (DECRP/NYS GIS Clearinghouse) maintains vectors
of the wetland areas already, e.g. these are loaded into
OpenStreetMap, metadata in the data layer there.
  http://www.openstreetmap.org/?lat=40.59313&lon=-73.60279&zoom=15&layers=M
hmmm, but maybe only protected/listed/named areas are covered?

also the ENC version of the nautical chart can be imported with
v.in.ogr's S-57 driver, and you can extract the features that
way (but s57 is a bit ugly to work with in this context)


Hamish


      
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