[mkgmap-dev] Re: ASTER elevation data

Wed Jul 1 00:03:26 BST 2009

0> In article <4A4A84BD.2090801 at gmx.de>,
0> Christian Gawron <URL:mailto:christian.gawron at gmx.de> ("CG") wrote:

CG> I already wrote a class to read SRTM data directly with mkgmap,
CG> i.e. without having to create the contours as separate (huge) files.

0> In article <af62527b0906301439t7472b68fofd2770753eeb36a5 at mail.gmail.com>,
0> Ben Konrath <URL:mailto:ben at bagu.org> ("Ben") wrote:

Ben> This feature seems really cool! I'm looking forward to trying it
Ben> out.

Seconded - although don't overlook the benefit of saving generated
contours in big files, as they are computed very rarely, but the OSM
data change frequently.

Christian - does your contour generation attempt any curve fitting, or
does it use the linear-interpolation-along-cell-edges algorithm as in
gdal_contour (which is what I currently use to generate contours from
GeoTIFF files)?

A final warning on the ASTER data - the web site says that the data are
free for "any users (individual/organization) who conduct work or
research in 9 societal benefit areas (disaster, health, energy, climate,
weather, ecosystem, agriculture, and biodiversity) defined by GEOSS
(Global Earth Observation System of System)"[1].  Presumably others are
not so entitled; there also seems to be restrictions on distributing
derived works (e.g. posting generated Garmin OSM maps with ASTER
contours).

[1] <URL: http://www.ersdac.or.jp/GDEM/E/3.html >