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(Physical Geography) a line on a map connecting places registering the same amount or ratio of some geographical or meteorological phenomenon or phenomena. Also called: isogram or isoline
[C20: from Greek isoplēthēs equal in number, from iso- + plēthos multitude, great number]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014


(ˈaɪ səˌplɛθ)

a line drawn on a map through all points having the same numerical value, as of a population figure or geographic measurement.
[1905–10; < German Isoplethe (1877) < Greek isoplēthḗs equal in number]
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.isopleth - a line drawn on a map connecting points having the same numerical value of some variable
isobar - (meteorology)an isogram connecting points having equal barometric pressure at a given time
isochrone - an isogram connecting points at which something occurs or arrives at the same time
isoclinal, isoclinic line - an isogram connecting points of equal magnetic inclination
isohel - an isogram connecting points receiving equal amounts of sunshine
isotherm - (meteorology) an isogram connecting points having the same temperature at a given time
line - a spatial location defined by a real or imaginary unidimensional extent
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.
References in periodicals archive ?
The 80 % isopleth was the mean core for all specimens (n = 12 ranges, mean [+ or -] SD = 80, 4 [+ or -] 4.5 %), selected by examining the utilization distribution curves (% of area plotted against % of locations; Powell 2000).
A smooth isopleth map was computed to visually represent the geographical heterogeneity of the indicator and capture its salient spatial structure.
We used the 30% isopleth to identify areas with the highest density values for these two distributions (Benhamou and Riotte-Lambert, 2012).
A combination analysis of E and isopleth ratio (Lc/La) was used to determine the goby fishing status based on the method of Pauly and Soriano (1986).
Therefore, some serious analyses of local regions in those countries should be performed providing basic information on the climatic loads, for example, in the form of the isopleth or contour maps.
Yield isopleth: Yield isopleth was plotted to identify the impact of changes in exploitation ratio (E) on yield (critical length ratio (Lc)= [Lc.sub.50]/[L.sub.[infinity]).
The 95% isopleth, that represents the time interval, in a 24 h period, in which 95% of activity occurs was considered the activity range (Oliveira-Santos et al., 2013).
boddartiwas compared to the anticipated values of E max (the maximum yield exploitation rate), E 0.1 (the exploitation rate with the minimal increase of 10% of (Eq.) when E close tozero), and E 0.5 (the exploitation rate in which the reduction of stock to 50% of the unexploited biomass).The knife-edge selection was used to estimate the values of E max, E 0.1 andE 0.5 (Beverton and Holt 1966).The ratio of length at first catch and asymptotic length (L c /L[?]) was determined using the yield isopleth diagram that was used to estimate the fishing status of B.
Core areas are often estimated using an arbitrarily designated isopleth value applied across all individuals in a study (Vander Wal and Rodgers 2012).
In the southern zone, the displacement of the isopleth of 120 kg km-[linear.sup.-1] registered a gradual northward movement according to the increase of abundance from 2006 around 35[degrees]S, to near 32[degrees]S in 2011 (Fig.