wwp@yahoogroups.com:
Re: OT: The center of a landmass
Bostjan Burger 2009-Jul-04 11:22:00
Geometric centre of the country depends on
the definition of the borders of the country. From the geographic point of view the
geometric centre of the country is only an entertainment and for funs not a real
value?in most cases. Sometimes it is used the term the
geographic centre which is for me professionally completely other thing than
geometric centre and can not be measured mathematically? but it is true the geographic
centre is in general used as a geometric centre if I want so or not? From your
question I aspect that you meant geometric centre of the country? so the answer
would be how to define a centroid which is the geometric center of the object's
shape. First you need a shapefile of the country (there can be a problem as some
shp files are without water ? sea areas, some are with...), which is actually a polygon.
Each shp file consist also a CNT (Polygon Centroid Coordinates) when you look
at it there are three fields: number of labels in polygon and that what you
want: centroid x and centroid y.
I use ArcMap format analysis but http://map-suite--winforms-edition.spatially-aware.downloadsoftware4free...
should help. You can find some more interesting at: http://www.maptools.org/ or http://mitab.maptools.org/.
Bostjan
--- On Fri, 7/3/09, Jakob Norstedt-Moberg <#removed#> wrote:
From: Jakob Norstedt-Moberg <#removed#>
Subject: OT: The center of a landmass
To: #removed#
Date: Friday, July 3, 2009, 9:37 PM
Does anybody know a modern (e.g. google maps based) tool to compute the center of a landmass like a country. The center could be defined in many ways (e.g. depending on how to treat the lakes and also depending on the selected map projection) but I would like to find at least one legitime way to calculate it.
Background:
The center of Sweden is said to be located at "Flataklacken" west of the town Sundsvall. This was estimated about 70 years ago by balancing a rigid cut-out map of Sweden on a needle to find its center of gravity. There must be better ways today, but how?
Jakob
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