Populated Places
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About
+Point symbols with name attributes. Includes all admin-0 and many admin-1 capitals, major cities and towns, plus a sampling of smaller towns in sparsely inhabited regions. We favor regional significance over population census in determining our selection of places. Use the scale rankings to filter the number of towns that appear on your map.
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LandScan derived population estimates are provided for 90% of our cities. Those lacking population estimates are often in sparsely inhabited areas. We provide a range of population values that account for the total “metropolitan” population rather than it’s administrative boundary population. Use the PopMax column to size your town labels. Starting in version 1.1, popMax has been throttled down to the UN estimated metro population for the ~500 largest urban areas in the world. This affects towns in China, India, and parts of Africa where our Landscan counting method usually over estimated.
+Population estimates were derived from the LANDSCAN dataset maintained and distributed by the Oak Ridge National Laboratory. These data were converted from raster to vector and pixels with fewer than 200 persons per square kilometer were removed from the dataset as they were classified as rural. Once urban pixels were selected, these pixels were aggregated into contiguous units. Concurrently Thiessen polygons were created based on the selected city points. The Thiessen polygons were used to intersect the contiguous city boundaries to produce bounded areas for the cities. As a result, our estimates capture a metropolitan and micropolitan populations per city regardless of administrative units.
+Once intersected, the contiguous polygons were recalculated, using aerial interpolation assuming uniform population distribution within each pixel, to determine the population total. This process was conducted multiple times, for each scale level, to produce population estimates for each city at nested scales of 1:300 million, 1:110 million, 1:50 million, 1:20 million, and 1:10 million.
+Population ranks
+Are calculated as rank_max and rank_min using this general VB formula that can be pasted into ArcMap Field Calculator advanced area (set your output to x):
+++a = [pop_max]
+if( a > 10000000 ) then +x = 14 +elseif( a > 5000000 ) then +x = 13 +elseif( a > 1000000 ) then +x = 12 +elseif( a > 500000 ) then +x = 11 +elseif( a > 200000 ) then +x = 10 +elseif( a > 100000 ) then +x = 9 +elseif( a > 50000 ) then +x = 8 +elseif( a > 20000 ) then +x = 7 +elseif( a > 10000 ) then +x = 6 +elseif( a > 5000 ) then +x = 5 +elseif( a > 2000 ) then +x = 4 +elseif( a > 1000 ) then +x = 3 +elseif( a > 200 ) then +x = 2 +elseif( a > 0 ) then +x = 1 +else +x = 0 +end if
Issues
+While we don’t want to show every admin-1 capital, for those countries where we show most admin-1 capitals, we should have a complete set. If you find we are missing one, please log it in the Cx tool at right.
+Version History
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