Spring 2011 Lapham’s Quarterly, “Lines of Work”
(Source: laphamsquarterly.org)
Posts tagged with space
(Source: psych-facts)
one can basically describe each of the classical geometries (Euclidean, affine, projective,spherical, hyperbolic, Minkowski, etc.) as a homogeneous space for its structure group.
The structure group (or gauge group) of the class of geometric objects arises from isomorphisms of one geometric object to the standard object of its class.
For example,
- • the structure group for lengths is
ℝ⁺
;- • the structure group for angles is
ℤ/2ℤ
;- • the structure group for lines is the affine group
Aff(ℝ)
;- • the structure group for
n
-dimensional Euclidean geometry is the Euclidean groupE(n)
;- • the structure group for oriented 2-spheres is the (special) orthogonal group
SO(3)
.
Economic geography of the eastern USA
circa 1999, median incomes by zip code
Code and data source to follow in a longer post.
Forestry is the province of variability.
From a spatial point of view this variability ranges from within-tree variation (e.g. modeling wood properties) to billions of trees growing in millions of hectares (e.g. forest inventory).
From a temporal point of view we can deal with daily variation in a physiological model to many decades in an empirical growth and yield model.
(Source: quantumforest.com)