▁convey ▁the ▁information ▁of ▁this ▁alternate ▁variable . ▁They ▁are ▁primarily ▁used ▁to ▁display ▁emphas is ▁and ▁for ▁analysis ▁as ▁nom ograph s . ▁ ▁Two ▁common ▁types ▁of ▁cart og rams ▁are ▁area ▁and ▁distance ▁cart og rams . ▁ ▁Cart og rams ▁have ▁a ▁fairly ▁long ▁history , ▁with ▁examples ▁from ▁the ▁mid - 1 8 0 0 s . ▁ ▁Area ▁cart og rams ▁▁ ▁An ▁area ▁cart ogram ▁is ▁sometimes ▁referred ▁to ▁as ▁a ▁value - by - area ▁map ▁or ▁an ▁is ode m ographic ▁map , ▁the ▁latter ▁particularly ▁for ▁a ▁population ▁cart ogram , ▁which ▁illustr ates ▁the ▁relative ▁sizes ▁of ▁the ▁populations ▁of ▁the ▁countries ▁of ▁the ▁world ▁by ▁scaling ▁the ▁area ▁of ▁each ▁country ▁in ▁proportion ▁to ▁its ▁population ; ▁the ▁shape ▁and ▁relative ▁location ▁of ▁each ▁country ▁is ▁retained ▁to ▁as ▁large ▁an ▁extent ▁as ▁possible , ▁but ▁in ev it ably ▁a ▁large ▁amount ▁of ▁dist ort ion ▁results . ▁Other ▁syn onym s ▁in ▁use ▁are ▁an am orph ic ▁map , ▁density - equal izing ▁map ▁and ▁Gast ner ▁map . ▁ ▁Area ▁cart og rams ▁may ▁be ▁cont igu ous ▁or ▁non cont igu ous . ▁The ▁area ▁cart og rams ▁shown ▁on ▁this ▁page ▁are ▁all ▁cont igu ous , ▁where ▁all ▁areas ▁are ▁connected ▁together ▁and ▁continu ously ▁de formed , ▁while ▁a ▁good ▁example ▁of ▁a ▁non cont igu ous ▁cart ogram ▁was ▁published ▁in ▁The ▁New ▁York ▁Times , ▁where ▁each ▁area ▁is ▁dis connected