Due to some problems concerning file naming and filesystem errors, I decided to completely restart from scratch. I have dropped all blanks from the file naming scheme, and prefixed them so there are no leading dashes in any of the filenames. Further, it proceeds much faster now for the folloiwing reasons:
- During the first run, all SRTM data have been downloaded and cached. The current run thus does not need to download a single file anew.
- Instead of running one script, I now run 4 scripts at once, each processing one quadrant of the earth’s surface. This will much better exploit the two cores of my CPU.
- I purchased a 500GB external hard drive so disc space won’t be an issue and won’t delay the processing.
I’m really curious how long it will need to complete the job. I started at 2008-11-02 00:23 CET (UTC+1). According to the amount of files generated during the first hour, it will last around 20 or 30 hours to generate all 64,800 tiles. But as areas just covered with water need almost no processing and will result in an almost empty XML file, hilly and especially mountainous areas will need much more CPU time and will thus protract the whole thing. Anyway, at the time of this writing (yes, it’s really late now :) the script is running more than two hours and has processed over 5000 out of 64800 tiles, quickly approximating the 10% mark.
Edit: After 10 hours, ca. 16,200 tiles have been processed. This is one quarter of all tiles and indicates that the whole run will last approximately 40 hours.
