Reads by specific chromosome and location:
Reads on CHR:chr1 LOC:100 = 3
Reads on CHR:chr1 LOC:500 = 0
Reads on CHR:chr2 LOC:200 = 2
Reads on CHR:chr3 LOC:100 = 0
Reads with positive counts by chromosome and location:
Reads on CHR:chr1 LOC:100 = 3
Reads on CHR:chr1 LOC:200 = 1
Reads on CHR:chr1 LOC:300 = 3
Reads on CHR:chr2 LOC:100 = 1
Reads on CHR:chr2 LOC:200 = 2