User:Wenslayer/KMLGenerator

Problem

Have you wondered what historical Geohashes have occurred in your graticule? Have you wanted to see them all at once, instead of typing each date in via peeron? Well this script might help you out here.

Solution

I've submitted a script to the Perforce Public Depot; the script can be downloaded here:

• gen_geohash_kml.pl

Kudos to Polysylabic Pseudonym for providing the Geohashing historical coordinates.

Usage

Usage: ./gen_geohash_kml.pl -g <graticule> [-i <input file>] [-n <name>] [-l] [-v]
        -g: graticule of interest (format: <latitude,longitude>)
        -i: input file to use (file format: YYYY-MM-DD,<DOW>,<LAT>,<LON>)
                default: '-' for standard input
        -n: name of top-level KML folder holding place markers
                default: "Geohash History for {graticule}"
                ("{graticule}" is replaced with actual graticule supplied)
        -l: generate a label for each place marker corresponding to its date
                default is to suppress a label for the place marker
        -v: enable verbose logging

Notes:
* You can get *all* retro Geohash data from:
  http://www.amipsychic.net/geohashing.html
* Resulting KML file is displayed to standard out.
* You may wish to pre-process the source file to only show dates of interest.
  E.g.: grep "^2009" allcoords.csv | ./gen_geohash_kml.pl -g 49,-123 > 2009.kml

Reference:
* http://wiki.xkcd.com/geohashing

Examples

Using the source data, Geohash coordinates can be generated for every day since October 1st, 1928 (over 80 years worth), so with a little filtering, you should be able to generate a KML file for whatever date range and graticule you'd like.

Victoria Geohash coordinates since 2008-05-21. Note how few Geohash coordinates actually fall in Victoria and the Saanich Peninsula?

Examples:

• Generate a KML for the Surrey graticule of all possible Geohash coordinates since October 1st, 1928 (over 29,000 points!):

$ wget -qO - http://www.amipsychic.net/coords/allcoords.csv.bz2 |
      bzip2 -d | gen_geohash_kml.pl -g 49,-122 > 49,-122_all.kml

• Generate a KML for the Vancouver graticule of all Canada Day and Christmas Day dates, with each place marker having a label (its date), and modifying the name of the set of place markers:

$ wget -qO - http://www.amipsychic.net/coords/allcoords.csv.bz2 |
      bzip2 -d | sed -nre '/-(07-01|12-25)/p' |
      gen_geohash_kml.pl -g 48,-123 -l -n "Geohash coords for Canada/Christmas Day in {graticule}" > 48,-123_7.1_12.25.kml

• Generate a KML for the Victoria graticule of all dates since the original Geohash webcomic (May 21st, 2008):

$ wget -qO - http://www.amipsychic.net/coords/allcoords.csv.bz2 |
      bzip2 -d | sed -ne '/^2008-05-21/,$p' |
      gen_geohash_kml.pl -g 49,-123 > 49,-123_since_2009-05-21.kml

To Do

1. Convert script from Bash to Perl to run faster.
   • Done, parsing all the data only takes a few seconds now, as opposed to many minutes.
2. Automate retrieval and decompression of source data.
   • Punted; I'd rather not, mostly due to The Art of Unix Programming's Rule of Composition: Design programs to be connected with other programs.
3. Pretty-up each placemark's description to include hyperlinks to this Wiki and peeron map.
   • Done; don't need link to peeron map (you're in a mapping application already!).
4. Add format checking of source data.
   • A few regex's, combined with some numeric range testing ought to do the trick.
5. Properly account for W30 graticules.
   • Punted, due to #2, this would be left for an exercise to the user.
6. Add option to display labels for each place marker.
   • Done.
7. Add option to override default <name> tag for KML document.
   • Done.
8. Add ability to specify more than one graticule at a time.
   • May involve adding support to read from a config file.