I have downloaded a dataset (which documents nucleosome postioning in hESCs) that took almost 4 hours to transfer to my system. And I am using the following script to convert the data to a bed file:

curl ftp://ftp-trace.ncbi.nlm.nih.gov/sra/sra-instant/reads/ByExp/sra/SRX/SRX645/SRX645331/SRR1781834/SRR1781834.sra>SRR1781834.sra

fastq-dump ./SRR1781834.sra

# in the case of single-end reads, there are two input files for mapping:
bowtie -t -v 2 -p 8 -m 1 --solexa-quals mm9 SRR1781834.fastq SRR1781834.map

# in case you have used Boutie at the previous step, now you have to convert the file fom .map to .bed
perl -w /storage/projects/teif/scripts/bowtie2bed.pl SRR1781834.map SRR1781834.bed

I was told that this was a fairly logical way to convert sra files to bed files and yet the output in the final bed file is as follows:

chr1    16972827        16972927        U2      0       +
chr1    169261752       169261852       U2      0       -
chr10   14618525        14618625        U2      0       +
chr10   32927157        32927257        U2      0       -
chr10   36893563        36893663        U2      0       +
chr10   71759925        71760025        U2      0       -
chr10   71759929        71760029        U2      0       +

NOTE: the start and end position only documents the analysis of single nucleotide positions (this dataset should be documenting entire portions of chromosomes)....

Below is the documented descent in the size of the files as the script progresses (notice how the file size decreases with each new ouput):

-rw-r--r-- 1   15G Dec  9 16:49 SRR1781834.sra
-rw-r--r-- 1   73G Dec  9 17:03 SRR1781834.fastq
-rw-r--r-- 1   18K Dec  9 18:02 SRR1781834.map
-rw-r--r-- 1  1.9K Dec 11 14:19 SRR1781834.bed
-rw-r--r-- 1  1.9K Dec 11 14:25 SRR1781834_sorted.bed

My question is how is the data of such a large SRA file translating into such a small bed file?..... Am I doing this wrong and how can I improve my file conversion strategy to get more informative data?