Merge pull request #9 from nobuf/master

Fix download uri since previous one returns 404

Makefile

@@ -1,38 +1,40 @@
 TOPOJSON = node_modules/.bin/topojson
 TOPOMERGE = node_modules/.bin/topojson-merge
+# http://www.naturalearthdata.com/downloads/
+NATURAL_EARTH_CDN = http://naciscdn.org/naturalearth
 
 all:
 
 .SECONDARY:
 
 zip/ne_10m_land.zip:
 	mkdir -p $(dir $@)
-	curl "http://www.nacis.org/naturalearth/10m/physical/ne_10m_land.zip" -o $@.download
+	curl "$(NATURAL_EARTH_CDN)/10m/physical/ne_10m_land.zip" -o $@.download
 	mv $@.download $@
 
 zip/ne_10m_%.zip:
 	mkdir -p $(dir $@)
-	curl "http://www.nacis.org/naturalearth/10m/cultural/ne_10m_$*.zip" -o $@.download
+	curl "$(NATURAL_EARTH_CDN)/10m/cultural/ne_10m_$*.zip" -o $@.download
 	mv $@.download $@
 
 zip/ne_50m_land.zip:
 	mkdir -p $(dir $@)
-	curl "http://www.nacis.org/naturalearth/50m/physical/ne_50m_land.zip" -o $@.download
+	curl "$(NATURAL_EARTH_CDN)/50m/physical/ne_50m_land.zip" -o $@.download
 	mv $@.download $@
 
 zip/ne_50m_%.zip:
 	mkdir -p $(dir $@)
-	curl "http://www.nacis.org/naturalearth/50m/cultural/ne_50m_$*.zip" -o $@.download
+	curl "$(NATURAL_EARTH_CDN)/50m/cultural/ne_50m_$*.zip" -o $@.download
 	mv $@.download $@
 
 zip/ne_110m_land.zip:
 	mkdir -p $(dir $@)
-	curl "http://www.nacis.org/naturalearth/110m/physical/ne_110m_land.zip" -o $@.download
+	curl "$(NATURAL_EARTH_CDN)/110m/physical/ne_110m_land.zip" -o $@.download
 	mv $@.download $@
 
 zip/ne_110m_%.zip:
 	mkdir -p $(dir $@)
-	curl "http://www.nacis.org/naturalearth/110m/cultural/ne_110m_$*.zip" -o $@.download
+	curl "$(NATURAL_EARTH_CDN)/110m/cultural/ne_110m_$*.zip" -o $@.download
 	mv $@.download $@
 
 # Admin 0 – land (3.17M)