Hack 59. Geocode Your Voice Recordings and Other Media

One way to make a chunk o'media better is to know where it was created!

We talk about geocoding photographs elsewhere (see [Hack #39] ), but what about other media? How about that digital voice recorder? A recording athletic heart-rate monitor? Even SMS messages have timestamps. If you have GPS tracklogs, then you can use a simple web site to geocode anything! The trick is to use timestamps and tracklogs to determine where you were when you created a file.

You can geocode any media that has a timestamp using the linkmedia tool at http://mappinghacks.com/projects/linkmedia/. This hack uses the linkmedia.cgi script that is included with the Perl module Geo::Track::Log. Select the link to "linkmedia," and you get the web page shown in Figure 5-35.

Figure 5-35. linkmedia.cgi file selection page

This program lets you upload a text file that I call a "media description file," along with a GPX-format tracklog file. A media description file contains one line for each item to be geocoded. The first field is a filename, followed by the pipe symbol (|), and a date and timestamp, followed by another pipe. Anything else can appear after the date and timestamp. Here is a sample line from a media description file:

random.txt|2004-04-03 19:23|

You can create the media description file in any text editor for any media that you have. For example, you can create a media description file for a list of photographs. As it happens, I created this module so that I could geocode audio files and create audio travelogues. I have an Olympus DS-330 Digital Voice Recorder that allows me to record sound clips and download them to my computer in individual DSS format files. Each file contains a header with the date and time that the clip was started, and some other information. I created the Perl module Audio::DSS to extract this metadata and output it in the media description file format.

Audio::DSS is available on CPAN. It includes the script dumpdss.pl that extracts DSS-file metadata. The script is in the eg/ directory. Copy dumpdss.pl to somewhere in your path, and then change directories to your audio file directory.

$ dumpdss.pl FolderB/*.dss

Here is a partial list of these files, along with their metadata. The first field is the filename; the second is the date the sound clip was started, when it was completed, the time in seconds, and a comment. The DSS Recorder software lets you add a comment of up to 100 characters. The first time I tried to do this I was reminded of the importance of synchronizing the time on my voice recorder with my GPS:

FolderB/DS330271.dss|2004-09-06 21:22:55|2004-09-06 21:23:06|000010|Start Segment|
FolderB/DS330278.dss|2004-09-06 21:24:32|2004-09-06 21:24:52|000020|Why is it that 
FolderB/DS330279.dss|2004-09-06 21:29:21|2004-09-06 21:29:28|000007|News on 
the radio|
FolderB/DS330343.dss|2004-09-06 21:38:53|2004-09-06 21:39:45|000052|Rock'M Sock'M 
robot action!|

You can geocode the media description file and output a media description file with latitude and longitude added to it by clicking on "link media."

39.589177|-119.441896|FolderB/DS330271.dss|2004-09-06 21:22:55|2004-09-06 21:23:06|
000010|Start Segment|
39.582250|-119.469884|FolderB/DS330278.dss|2004-09-06 21:24:32|2004-09-06 21:24:52|
Why is it that color?|
39.555830|-119.561804|FolderB/DS330279.dss|2004-09-06 21:29:21|2004-09-06 21:29:28|
News on the radio|
39.529747|-119.728585|FolderB/DS330343.dss|2004-09-06 21:38:53|2004-09-06 21:39:45|
Rock'M Sock'M robot action!|

But wait, there's more! If you click on "show track stats," you will get statistics about your GPX file, as shown in Figure 5-36.

Figure 5-36. GPX Tracklog statistics

I've long been interested in the geospatial component of what people do, since everything that people do has a geospatial component. After all, we are somewhere whenever we do anything. This tool does not actually require a GPS unit or a real tracklog. As shown in [Hack #98], you can geocode historic documents and events, and then use tools like these to extend the narrative and add additional context.

See http://mappinghacks.com/projects/linkmedia/ for more on geocoding, mapping arbitrary media, and creating online voice-annotated travelogues.

Mapping Your Life

Mapping Your Neighborhood

Mapping Your World

Mapping (on) the Web

Mapping with Gadgets

Mapping on Your Desktop

Names and Places

Building the Geospatial Web

Mapping with Other People

Mapping Hacks
Mapping Hacks: Tips & Tools for Electronic Cartography
ISBN: 0596007035
EAN: 2147483647
Year: 2004
Pages: 172

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