<table cellspacing="0" cellpadding="0" border="0" ><tr><td valign="top" style="font: inherit;">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. <br><br>Thanks for the tip on the S-57 driver, it is not something that I was aware of.<br><br>--- On <b>Wed, 11/10/10, Hamish <i><hamish_b@yahoo.com></i></b> wrote:<br><blockquote style="border-left: 2px solid rgb(16, 16, 255); margin-left: 5px; padding-left: 5px;"><br>From: Hamish <hamish_b@yahoo.com><br>Subject: Re: [GRASS-user] r.thin ?<br>To: "charlie" <carowan@yahoo.com><br>Cc: "GRASS user list" <grass-user@lists.osgeo.org><br>Date: Wednesday, November 10, 2010, 6:02 AM<br><br><div class="plainMail">charlie wrote:<br>> In response to your questions, I am trying to convert a raster<br>> map (a scanned & georeferenced map with only XY
data)<br>> with a shoreline and some wetland islands into a vector map<br>> so I can compare gains/losses over time.<br>><br>> A preview of the map is here: <a href="http://historicalcharts.noaa.gov/tiled_jpgs_done/zoomifyURLDrivenWebPage.htm?zoomifyImagePath=579-12-1929" target="_blank">http://historicalcharts.noaa.gov/tiled_jpgs_done/zoomifyURLDrivenWebPage.htm?zoomifyImagePath=579-12-1929</a><br><br>if I am getting that right, the area is Hempsted Bay?<br>if so fyi NY DEC (DECRP/NYS GIS Clearinghouse) maintains vectors<br>of the wetland areas already, e.g. these are loaded into<br>OpenStreetMap, metadata in the data layer there.<br> <a href="http://www.openstreetmap.org/?lat=40.59313&lon=-73.60279&zoom=15&layers=M" target="_blank">http://www.openstreetmap.org/?lat=40.59313&lon=-73.60279&zoom=15&layers=M</a><br>hmmm, but maybe only protected/listed/named areas are covered?<br><br>also the ENC version of the
nautical chart can be imported with<br>v.in.ogr's S-57 driver, and you can extract the features that<br>way (but s57 is a bit ugly to work with in this context)<br><br><br>Hamish<br><br><br> <br></div></blockquote></td></tr></table>