<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:times new roman, new york, times, serif;font-size:14pt"><br><div style="font-family: times new roman,new york,times,serif; font-size: 14pt;"><div style="font-family: arial,helvetica,sans-serif; font-size: 13px;">----- Original Message ----<br>From: Keith Sharp <kms@passback.co.uk><br>To: talk@openstreetmap.org<br>Sent: Monday, 15 September, 2008 21:17:59<br>Subject: Re: [OSM-talk] Own maps with hill shading and routes using mapnik<br><br>>I considered something similar to mapping lakes and lochs - use my GPS<br>>with barometric altimeter to measure the elevation of the surface of the<br>>water and then use the SRTM data to work out the contour that<br>>corresponds to the edge of the water. Hey presto, instant loake or loch<br>>map!<br><br>I've spent quite a lot of time adding lakes in Peru, based on the yahoo
imagery. However I'm aware that the imagery is not generally high
resolution and hence the accuracy of this approach is poor (but better
than nothing). I've just come across this page:
http://wiki.openstreetmap.org/index.php/HikingBikingMaps explaining how
to set up the software, and was going to have a play. The theory is
that if the SRTM data include an altitude reading for the lake itself
(I haven't actually checked this yet!), I should be able to use an
approach similar to what you suggest to get a much more accurate map.
The holy grail would be to be able to click somewhere within a lake,
and the software to automatically generate a perimeter. However I
suspect that will be a long way off, if it ever happens.<br><br>>I never got round to implementing anything because I discovered most of<br>>the bodies of water in Scotland had been mapped.<br><br>We're quite lucky in the UK as far as having keen mappers is concerned, but when I first started doing Peru (a country I know well) there was virtually nothing on the map at all. My aim has been to get as much of the basic geographical infrastructure added as is possible using the satellite imagery (mainly rivers and lakes), as a means of encouraging local mappers to get involved. It's quite heartening to see that now there is quite a bit of mapping activity in the country. Just because your own country is covered doesn't mean the idea isn't worth pursuing!!<br><br>Donald<br>_______________________________________________<br>talk mailing list<br><a ymailto="mailto:talk@openstreetmap.org"
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