Intensity maps from point data. CartoCSS

gistfile1.txt

/*map: cdb.io/VGx3Ko */

#madrid_mercados {
    first/marker-fill: #f2ff00;
	  first/marker-opacity: 0.01;
	  first/marker-width: 80;
	  first/marker-line-width: 0;
	  first/marker-placement: point;
	  first/marker-allow-overlap: true;
  	  first/marker-comp-op: lighten;
  
	  second/marker-fill: #ffa754;
	  second/marker-opacity: 0.03;
	  second/marker-width:50;
	  second/marker-line-width: 0;
	  second/marker-placement: point;
	  second/marker-allow-overlap: true;
  	  second/marker-comp-op: lighten ; 
  
	  third/marker-fill: #ff1402;
	  third/marker-opacity: 0.05;
	  third/marker-width:20;
	  third/marker-line-width: 0;
	  third/marker-placement: point;
	  third/marker-allow-overlap: true;
  	  third/marker-comp-op: lighten ; 
	}