anchor.diff:  "ST7","382200","354600","53.08802","-2.26580","Kidsgrove","Staffordshire","ENG","England"
   "ST8","388800","357600","53.11517","-2.16735","Biddulph","Staffordshire","ENG","England"
   "ST9","393400","350400","53.05052","-2.09847","Bagnall","Staffordshire","ENG","England"
  -"SW1","529200","179100","51.49558","-0.13860","Westminster","London","ENG","England"
  +"SW1","529200","179100","51.49558","-0.13860",,"Westminster","ENG","England"
   "SW10","526300","177700","51.48365","-0.18086","Kensington","Greater London","ENG","England"
   "SW11","527500","175800","51.46630","-0.16427","Wandsworth","Greater London","ENG","England"
   "SW12","528700","173500","51.44536","-0.14784","Wandsworth","Greater London","ENG","England"
  
positive.code: "PH40","169900","792200","56.96381","-5.78560",,"Highland","SCT","Scotland"
  "PH41","167300","796800","57.00374","-5.83251","Mallaig","Highland","SCT","Scotland"
  "PH42","147900","786600","56.90217","-6.14094","Isle Of Eigg","Highland","SCT","Scotland"
  "PH43","140200","799700","57.01529","-6.28049","Isle Of Rum","Inverness-shire","SCT","Scotland"
  "PH44","127000","805200","57.05693","-6.50319","Isle Of Canna","Highland","SCT","Scotland"
  "PH49","209500","758000","56.67500","-5.10977","Glencoe","Highland","SCT","Scotland"
  "PH5","287000","716700","56.32927","-3.82770","Muthill","Perth and Kinross","SCT","Scotland"
  
negative.code: "WC1R","530700","181700","51.51860","-0.11604","Camden Town","Greater London","ENG","England"
  "WC1V","530500","181500","51.51685","-0.11899","Camden Town","Greater London","ENG","England"
  "WC1X","530700","182400","51.52489","-0.11578","Camden Town","Greater London","ENG","England"
  "WC2","530200","181100","51.51332","-0.12346",,"Westminster","ENG","England"
  "WC2A","530800","181400","51.51588","-0.11471","Camden Town","Greater London","ENG","England"
  "WC2B","530300","181300","51.51510","-0.12195",,"Westminster","ENG","England"
  "WC2E","530200","181000","51.51242","-0.12350",,"Westminster","ENG","England"
  "WC2H","529900","181100","51.51339","-0.12778","Camden Town","Greater London","ENG","England"
  "WC2N","530100","180700","51.50975","-0.12505",,"Westminster","ENG","England"
  "WC2R","530500","180900","51.51145","-0.11921",,"Westminster","ENG","England"
  "WD1","510700","195500","51.64692","-0.39984","Watford","Hertfordshire","ENG","England"
  "WD17","510300","197100","51.66138","-0.40512","Watford","Hertfordshire","ENG","England"
  "WD18","509700","195600","51.64801","-0.41426","Watford","Hertfordshire","ENG","England"
  