d3.js地理投影测试套件使用一些众所周知的位置作为测试数据。但是，相同位置的纬度/经度可能因测试而异。
为什么？
由于
~/workspace/d3/test/geo$ grep -r "San Francisco" *
albers-test.js: "San Francisco, CA": [[-122.42000000, 37.78000000], [ 107.44485839, 214.04820561]],
albers-test.js: "San Francisco, CA": [[-122.42000000, 37.78000000], [ -0.34818238, -0.03359981]],
albers-usa-test.js: "San Francisco, CA": [[-122.42000000, 37.78000000], [ 107.44485839, 214.04820561]],
albers-usa-test.js: "San Francisco, CA": [[-122.42000000, 37.78000000], [ -0.34818238, -0.03359981]],
azimuthal-equal-area-test.js: "San Francisco, CA": [[ -46.16620803, 77.04946507], [ 448.09318291, 57.65281089]],
azimuthal-equal-area-test.js: "San Francisco, CA": [[ -46.16620803, 77.04946507], [ -0.21271211, -1.28231459]],
azimuthal-equidistant-test.js: "San Francisco, CA": [[ -46.16620803, 77.04946507], [ 445.26741926, 40.61796552]],
azimuthal-equidistant-test.js: "San Francisco, CA": [[ -46.16620803, 77.04946507], [ -0.23155054, -1.39588023]],
conic-conformal-test.js: "San Francisco, CA": [[ -46.16620803, 77.04946507], [ 442.69098342, 47.64115003]],
conic-conformal-test.js: "San Francisco, CA": [[ -46.16620803, 77.04946507], [ -0.24872678, -1.34905900]],
conic-equal-area-test.js: "San Francisco, CA": [[ -46.16620803, 77.04946507], [ 433.22520615, 32.16847746]],
conic-equal-area-test.js: "San Francisco, CA": [[ -46.16620803, 77.04946507], [ -0.31183196, -1.45221015]],
conic-equidistant-test.js: "San Francisco, CA": [[ -46.16620803, 77.04946507], [ 437.79988730, 40.06576540]],
conic-equidistant-test.js: "San Francisco, CA": [[ -46.16620803, 77.04946507], [ -0.28133408, -1.39956156]],
equirectangular-test.js: "San Francisco, CA": [[ -46.16620803, 77.04946507], [ 359.13715001, 48.28497214]],
equirectangular-test.js: "San Francisco, CA": [[ -46.16620803, 77.04946507], [ -0.80575233, -1.34476685]],
gnomonic-test.js: "San Francisco, CA": [[ -46.16620803, 77.04946507], [ 323.76600022, -691.84169545]],
gnomonic-test.js: "San Francisco, CA": [[ -46.16620803, 77.04946507], [ -1.04156000, -6.27894464]],
mercator-test.js: "San Francisco, CA": [[ -46.16620803, 77.04946507], [ 359.13715001, -76.39503103]],
mercator-test.js: "San Francisco, CA": [[ -46.16620841, 77.04946502], [ -0.80575234, -2.17596687]],
orthographic-test.js: "San Francisco, CA": [[ -46.16620803, 77.04946507], [ 455.75069916, 103.81541376]],
orthographic-test.js: "San Francisco, CA": [[ -46.16620803, 77.04946507], [ -0.16166201, -0.97456391]],
stereographic-test.js: "San Francisco, CA": [[ -46.16620803, 77.04946507], [ 459.00877672, 123.45642208]],
stereographic-test.js: "San Francisco, CA": [[ -46.16620803, 77.04946507], [ -0.13994149, -0.84362385]],
transverse-mercator-test.js: "San Francisco, CA": [[ -46.16620803, 77.04946507], [ 455.53607488, 38.07095444]],
transverse-mercator-test.js: "San Francisco, CA": [[ -46.16620803, 77.04946507], [ -0.16309283, -1.41286030]],
~/workspace/d3/test/geo$