[Proj] Re: best projection for europe
Strebe at aol.com
Strebe at aol.com
Thu Dec 16 14:04:17 EST 2004
Several projections come to mind. Lambert conic conformal and Albers
equal-area conic will work reasonably well across all of Europe. Since I don't know
the north/south extents you want to display I can't recommend precise standard
parallels. The lore says to choose parallels that are 1/6th of the distance
north of the southernmost limit of your map and 1/6th of the distance south of
the northernmost limit of your map. Choosing the best standard parallels
requires rather more elaborate analysis, but the lore will certainly give you
something much better than you seem to be using now.
Lambert azimuthal equal-area will also give reasonable results for Europe
when centered in the middle of the region of interest. The stereographic could
also be used in the same way, but be aware that areal inflation will be
noticeable toward the outer areas of the map.
In a message dated 12/16/2004 4:35:45 AM 太平洋標準時, schabios at logi-track.com
> I'm in the need for a good projection for displaying maps of (parts of)
> europe. We currently have all our data in WGS84 long/lat format in our
> PostGIS database. Is there any projection that you can advise from your
> experience to use for the whole europe?
> Currently, we simply use long/lat as karthesian coordinates with some
> shortening on the y axis, which is acceptable for southern and middle
> europe, but gets weird in northern europe.
> Usually, one would use the well known UTM or Gauss-Kruger projections
> from the EPSG database for europe, but both divide the data into zones.
> This has two drawbacks. First, handling zones adds complexity to the
> code that I would prefer to avoid in the first releases. Second, when we
> "zoom out" to display the whole europe (from spain to slovakia, from
> italy to scandinavia), it is difficult to "glue" the zones together.
> If anyone has made some good experiences with a specific projection, I'd
> be happy to hear about it.
> Thanks a lot,
> markus schaber | dipl. informatiker
> logi-track ag | rennweg 14-16 | ch 8001 zurich
> phone +41-43-888 62 52 | fax +41-43-888 62 53
> mailto:schabios at logi-track.com | www.logi-track.com
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