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<font face="Times New Roman, Times, serif">Are these the kind of
maps you mean:<br>
<br>
<a class="moz-txt-link-freetext" href="http://www-personal.umich.edu/~mejn/cartograms/">http://www-personal.umich.edu/~mejn/cartograms/</a><br>
<br>
These are "cartograms", distorted maps on the basis of some sort
of density distributions. There is a complete book with hundreds
of examples:<br>
<br>
<a class="moz-txt-link-freetext" href="http://www.amazon.com/Atlas-Real-World-Daniel-Dorling/dp/0500514259">http://www.amazon.com/Atlas-Real-World-Daniel-Dorling/dp/0500514259</a><br>
<br>
The authors have made available the software
(<a class="moz-txt-link-freetext" href="http://www-personal.umich.edu/~mejn/cart/">http://www-personal.umich.edu/~mejn/cart/</a>). I got it working some
time ago, but you need to know a bit about low-level compiling.
Alternatively, there is a tool for ArcGIS
(<a class="moz-txt-link-freetext" href="http://blogs.esri.com/Info/blogs/gisedcom/archive/2009/10/16/exploring-data-using-cartograms-within-arcgis-desktop.aspx">http://blogs.esri.com/Info/blogs/gisedcom/archive/2009/10/16/exploring-data-using-cartograms-within-arcgis-desktop.aspx</a>).<br>
<br>
Cartograms are real fun, so I hope you can do something with them
for your subject.<br>
<br>
Cheers, <br>
<br>
Jan<br>
</font><br>
On 08/09/11 13:02, Mikael Rittri wrote:
<blockquote
cite="mid:E4AB3DD44D22854B819908379DE4AD4938861DF3@SETHNWS023.carmenta.se"
type="cite">
<pre wrap="">Carlo Bertelli wrote:
</pre>
<blockquote type="cite">
<pre wrap="">My idea is analysing each town cluster using a little sphere
(or ellipsoid) centered on the town whith an emisphere that
only covers the space of the region, so to show larger distances
in town (so to distinguish any abbey) and reduced distances far
from the town center.
</pre>
</blockquote>
<pre wrap="">
If I understand you right, you want your map to be distorted
in the same way as M. C. Escher's Balcony,
<a class="moz-txt-link-freetext" href="http://www.worldofescher.com/gallery/A3.html">http://www.worldofescher.com/gallery/A3.html</a>
where the central balcony is shown in a large (detailed) scale,
but surrounding areas are shown in much smaller scale.
In Escher's print, the scale has stabilized when you get to the
print edges, but that's not necessary.
I haven't seen such map projections used for cartography, except
for patriotic joke maps, where one's beloved home town or country
is shown in a much larger scale than the rest of the world. But
maybe such projections are used for statistical or economic maps,
as you suggest. I doubt there is anything appropriate in Proj.4,
though.
One could make a new kind of azimuthal map projection for this
purpose. The azimuth (direction) from the town center could be
preserved (because, why not?). The true distance from the town
center could be represented by a shorter map distance. The
mathematical function that converts true distance to map distance
should have slope 1 for short distances, but gradually get lower
slope. Something like arctan or tanh, perhaps.
Best regards,
Mikael Rittri
Carmenta
Sweden
<a class="moz-txt-link-freetext" href="http://www.carmenta.com">http://www.carmenta.com</a>
-----Original Message-----
From: <a class="moz-txt-link-abbreviated" href="mailto:proj-bounces@lists.maptools.org">proj-bounces@lists.maptools.org</a> [<a class="moz-txt-link-freetext" href="mailto:proj-bounces@lists.maptools.org">mailto:proj-bounces@lists.maptools.org</a>] On Behalf Of Carlo A. Bertelli (Charta s.r.l.)
Sent: den 7 augusti 2011 23:17
To: <a class="moz-txt-link-abbreviated" href="mailto:proj@lists.maptools.org">proj@lists.maptools.org</a>
Subject: [Proj] Little sphere projection
Hello,
I'm trying a simplistic approach to a topological representation. I'm mapping the possessions belonging to a group of abbeys in a regional space. Il works well at a small scale, but when the abbeys are clustered in major towns, the representation ties properties to the cluster and not to the single abbey. The fact is that towns (and
clustering) play a significant role in this story (yes this happens in the 18th century), asks for a better representation.
My idea is analysing each town cluster using a little sphere (or
ellipsoid) centered on the town whith an emisphere that only covers the space of the region, so to show larger distances in town (so to distinguish any abbey) and reduced distances far from the town center.
I think it should not be impossible to craft ad hoc projections, but I have no idea on how to do it. Could someone help me?
TIA
c
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</pre>
</blockquote>
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