Category Archives: Internet

IndieWeb, or how to avoid Digital Sharecropping

Thanks to the DorkbotPDX blog I found my way onto the website of this year’s IndieWebCamp, which took place in Portland June 25 & 26. Although I was saddened that I wasn’t in town for it, the projects that ended up being developed by the camp immediately grabbed my interest.

Although I had never been aware of the term “indie web” (which seems to have been around for almost 15 years, judging by this article from, I’ve been building my own independent web presence for more than four years. In the words of the IndieWebCamp home page:

Rather than posting content on many third-party silos of content, we should all begin owning the content we’re creating. Publish short status updates on your own domain, and syndicate to Twitter. Publish photos on your own domain, syndicate to Flickr, etc, etc.

For some good summaries of the ideas and goals of the IndieWebCamp, this article from GigaOm and this post from Mark Hendrickson are a great place to start, while each of the camp’s guests also have their own websites, each with a wealth of information.

While I’ve been using this domain for quite a while, it’s been in use alongside Facebook, Delicious (and Flickr, to a smaller degree) as a part of my web presence. However, since I ditched Facebook five or six months ago, I’ve been relying on this domain for more, and overall I’ve been pleased. However, as the IndieWebCamp is readily willing to admit, there is room for a lot of room for technical innovation in expanding the functionality of the indie web. Towards that end, I see three threads of work that I’m interested in pursuing:

  • Using my site for Flickr-like photo sharing. While this might include syndication to Flickr at some point, I mostly want a light-weight DIY solution to photo sharing.
  • Similarly, using my site for bookmarking. I really like the service that delicious offers, but I want to own the data and let delicious simply keep a copy of it (see for some ideas).
  • Finally, I’m hugely enamored of the work on delivery-agnostic messaging that took place at IndieWebCamp, which you can find details of here. Not only is it a ridiculously simple protocol, but it starts to address some real issues of a distributed social web, in that it allows two-party communication based solely on domain names as unique identifiers, therefore eliminating the middleman in social-web-type communications.
Hopefully I’ll have time to get one of these ideas worked out and running on my site soon (before school starts), so check back here soon, I’ll be sure to keep you posted.

Map Tiles with Python + GDAL

After getting GPSDrive running on OS X I started looking into different sources for maps. The GPSDrive wiki has a couple of interesting pages about this: one on creating maps and one on map sources. The second page pointed me to the LibreMap Project which has a complete collection of  USGS 1:24000 (large scale) topographic maps for the entire US. These files are distributed as high-resolution GeoTIFF files, along with world files, so the maps are fully geotagged. This means that they contain all of the information needed to generate GPSDrive-friendly map tiles, but GPSDrive will not read them directly. The creating maps page gives some (heavily out-of-date) advice on how to use the script distributed with GPSDrive to create map tiles using the tools from GDAL. Sadly, this script is completely unusable on OS X, because of incompatibilities in the command line tools that are used by the shell script. After spending about five minutes trying to tune it to work with the tools that Apple ships, I completely gave up and looked into other approaches.

Luckily, I quickly found out that GDAL ships with Python bindings. I installed GDAL from source using the instructions from their wiki. To make sure it built with Python modules I ran ./configure –with-python. After that make and sudo make install ran without a hitch.

I then set about re-implementing in Python. Once I got a handle on how to use the Python bindings it was fairly easy to write. You can find the script here.

Using is very similar to using

$ ./ -h
Usage: [options] FILENAME

  -h, --help            show this help message and exit
  -o OVERLAP, --overlap=OVERLAP
                        percentage tiles will overlap. should be at least 20%
  -a, --add             write map info to map_koord.txt in current working
  -m, --map             use *_map folders for output; use if input image is
                        UTM. Default behavior
  -t, --topo            use *_top folders for output; use if input image is
                        not UTM
  -v, --verbose         enable debugging output

The biggest difference is that does not perform any format conversion; it will write maps to TIFF files. Although the file size is decidedly larger than that of PNGs, my version of GDAL is unable to create PNGs, and disk space is (fairly) cheap. If I’m motivated I’ll get around to adding a format option, at least to allow conversion to PNG.

Running filename.ext will create a folder named filename_map (or _top, if you use the -t flag) that contains a set of 1280×1024 TIFF files, as well as a map_koord_draft.txt file. Moving this folder into GPSDrive’s map directory, and merging filename_[map|top]/map_koord_draft.txt with map_koord.txt will make the new maps available to GPSDrive. Note that filename.ext must be in the current working directory, as the script handles filenames/paths somewhat naivëly.

So far I’ve only tested this with GeoTIFFs from LibreMaps, but it seems to work great, with the caveat that LibreMaps’ files include the borders of map, and my script doesn’t do any cropping, so you see borders if you’re near the edges of quads. This doesn’t bother me terribly much, but you may need to turn mapsets on and off in the Map Control dialog to see the appropriate images.

Update 7-14-11: I’ve modified the script with an additional flag (-a) that will automatically merge the generated map_koords file with map_koord.txt in the current working directory. This means that if you run the script from inside .gpsdrive/maps with the -a flag the generated tiles will be automatically added to GPSDrive’s database. The script avoids creating duplicate entries in map_koord.txt, as well as alphabetizing all entries.

I’ve modified the documentation here, as well as the links, to reference the latest version.

Sign your email like Randall Waterhouse

Neal Stephenson’s novel Cryptonomicon is a fascinating book; I’m re-reading it for the umpteenth time and loving it every bit as much as when I first read it in 7th grade. One thing that caught my attention on this reading (especially in light of my recent GPS post) is the way that one of the main characters, Randall Lawrence Waterhouse, signs his email:

Randall Lawrence Waterhouse

Current meatspace coordinates, hot from the GPS receiver card in my laptop:

8 degrees, 52.33 minutes N latitude 117 degrees, 42.75 minutes E longitude

Nearest geographical feature: Palawan, the Philippines


Using GPSd’s python bindings, and the free, CC-licenced RESTful API from, I wrote a short python script that will produce a similar output:

Seth Just

Current meatspace coordinates, hot from the GPS receiver card in my laptop:

41.751 N latitude, 111.807 W longitude

Nearest geographical feature: Logan Canyon, Utah, United States

The core of the script is two functions — one that gets GPS coordinates from GPSd, and a second that does a lookup for geographical features (mountains, canyons, islands, etc) on For more details, see the final section of this post.


To use, first download it from here, and change the extension to .py.

In order to be useful as an email signature, I had to produce output in HTML format, which allows almost any mail client to use the output as a signature. I’ve gone through the effort of setting it up with the two clients I use the most: Mozilla Thunderbird and Apple’s Of these two, Thunderbird has documented support for HTML signatures (see here for details), and should be the most like other email clients. This script has been tested on Mac OS X Snow Leopard, and should run on Linux without problems (although I haven’t tried it on versions of python higher than 2.6.1).

Using takes two steps: first configure your Mail client to take a signature from a file, and then configure to run automatically to update that file.

Thunderbird is relatively easy to set up with an HTML signature. Because it only supports one signature per account, you simply need to tell it to draw that signature from a file. Under each account’s settings there’s an option to “Attach the signature from a file” (see here for a detailed howto). I chose to use ~/.signature.html, but you can use any file you’d like to, just remember the location you choose. is a more finicky beast — although the script supports it, I recommend using Thunderbird, mainly because Mail only refreshes its signatures from files on every launch, whereas Thunderbird will read the file each time you compose a message. However, if that limitation is acceptable (if you don’t move very much, perhaps), it will work just fine. The main issue with is that it doesn’t store signatures in an HTML file, but instead in the proprietary .webarchive format. These files can be found in ~/Library/Mail/Signatures. To use with Mail, you need to follow steps 4&5 from First create a new signature (under Preferences->Signatures). This will create a new file in the signature folder — take note of the file name. You will use this file name to configure is configured with command line options:

Usage: [options] NAME FILENAME
Note: NAME should be enclosed in quotes, unless it contains no spaces.

  -h, --help   show this help message and exit
  --no-gps     don't attempt to get coordinates from GPS
  -a, --amail  generate files for Apple's (.webarchive)
  --lat=LAT    default latitude, if GPS is unavailable
  --lon=LON    default longitude, if GPS is unavailable

The simplest way to use it is manually — simply running it whenever you want to update your signature. For example, I use ./ –lat=41.752 –lon=-111.793 ‘Seth Just’ ~/.signature.html to generate a signature for Thunderbird.

If you want to make this automatic, you’ll need to have the script run automatically. On OS X you’ll need to use launchd, while on linux you need cron. Both of these make setting up repeating actions very easy — see here for information on launchd and here for information on cron.

Sadly I haven’t yet figured out a way to run the script whenever you write an email — if I figure it out, I’ll be sure to post something.

The Script is built around three major functions — one gets coordinates from GPSd, one gets geographical feature information from

The function I use to get GPS information is a bit hacky — there doesn’t seem to be terribly much documentation on GPSd’s python bindings, so I made do with what I could figure out:

class NoGPSError (Exception): pass

def get_lat_lon():
  # GPSd Python bindings
  import gps

  # Create GPS object
  session = gps.gps()

  # Set GPS object as an iterator over reports from GPSd|gps.WATCH_NEWSTYLE)

  # Loop until we get a report with lat and lon. The limit of 5 loops should be more than enough -- my gps never takes more than three when it has a lock
  i = 0
  while (1):
      lat, lon =['lat'],['lon']
      if (i > 5): raise NoGPSError 
      i += 1

  return lat, lon

The other function is more straightforward — it makes two http requests to to get the nearest geographical feature and locality. It then combines those responses in a way that should provide a good response almost anywhere in the world (provided that GeoNames has good, local data). I’ve tested it with a variety of coordinates (provided by, and the responses seem to be pretty good.

def get_geo_string(lat, lon):
  # Modules for REST/XML request from GeoNames
  import urllib
  from xml.etree import ElementTree as ET
  # Request the name of the nearest geographical feature
  placename = ET.parse(
      urllib.urlopen("" + str(lat) + "&lng=" + str(lon) + "&featureClass=T&username=sethjust")
  subdiv = ET.parse(
      urllib.urlopen("" + str(lat) + "&lng=" + str(lon) + "&username=sethjust")
  # Format and return place, region, country
    country = subdiv.getiterator("countryName")[0].text
      country = placename.getiterator("countryName")[0].text
      country = ''
    region = subdiv.getiterator("adminName1")[0].text
    region = ''
    name = placename.getiterator("name")[0].text
    name = ''
  if country:
    if region:
      if name:
        result = "%s, %s, %s" % (name, region, country)
        result = "%s, %s" % (region, country)
      if name:
        result = "%s, %s" % (name, country)
        result = country
    result = "unknown"
  return result

Finally, the main method of the program parses arguments, determines what coordinates to use, gets the geographical feature string, and then generates the proper HTML and copies it into the correct place.

if (__name__ == "__main__"):
  # Parse command line options
  from optparse import OptionParser
  parser = OptionParser("Usage: %prog [options] NAME FILENAME\nNote: NAME should be enclosed in quotes, unless it contains no spaces.")
  parser.add_option("--no-gps", action="store_true", dest="nogps", default=False, help="don't attempt to get coordinates from GPS")
  parser.add_option("-a", "--amail", action="store_true", dest="amail", default=False, help="generate files for Apple's (.webarchive)")
  parser.add_option("--lat", action="store", type="float", dest="lat", help="default latitude, if GPS is unavailable")
  parser.add_option("--lon", action="store", type="float", dest="lon", help="default longitude, if GPS is unavailable")

  options, args = parser.parse_args()
  try: assert(len(args) == 2)
  except AssertionError:
    print "You must provide NAME FILENAME\n"

  try: assert(((!=None) & (options.lon!=None)) | (( & (options.lon==None)))
  except AssertionError:
    print "You must provide both lat and lon arguments\n"

  # Modules for creating signature file
  import tempfile, os

    if (options.nogps): raise NoGPSError
    lat, lon = get_lat_lon()
    print "Got %f, %f from gps" % (lat, lon)
  except NoGPSError:
    if (not options.nogps): print "Failed to get coordinates from GPS"
      assert((!=None) & (options.lon!=None))
    except AssertionError:
      print "No default coordinates provided; exiting"
    lat, lon =, options.lon
    print "Using %f, %f as coordinates" % (lat, lon)

  geostring = get_geo_string(lat, lon)

  lac, loc = 'N', 'E'
  if lat < 0:
    lat *= -1
    lac = 'S'
  if lon < 0:
    lon *= -1
    loc = 'W'

  file = tempfile.NamedTemporaryFile()


") file.write(args[0]) file.write("


") file.write("Current meatspace coordinates, hot from the GPS receiver card in my laptop:") file.write("


") file.write("%.3f %s latitude, %.3f %s longitude" % (lat, lac, lon, loc)) file.write("


") file.write("Nearest geographical feature: " + geostring) file.write("

\n") file.write("\n") file.flush() if (options.amail): os.system("textutil -convert webarchive -output " + args[1] + " " + else: os.system("cp " + + " " + args[1])

Submit an HTML form using the enter key, without JavaScript

I was delving into some simple PHP coding for the first time in a while, and was having trouble getting a form to submit when I pressed enter. Googling was ineffective, and only seemed to come up with javascript approaches, which I wanted to avoid. However, this StackOverflow question suggested the answer: add a


attribute to the submit button. I did this, and everything worked beautifully.

Update: Migratory Internet Junk

I know it’s taken me a long time to post this, but I received my box of migratory junk on May 10! I got box INTJ-7 which had been shipped out by a nice guy from San Diego. I don’t have a lot to say now (and no pictures) but I’d like to share some of what I got out of it. Perhaps my biggest find was right on top: a Hand Held Products IT4410 2D barcode scanner. On the product page I found the manual manual (pdf link) which explains all of its features.

HHP 4410HD Barcode Scanner

It turns out that the scanner emulates a PS/2 keyboard and will read almost any 1D or 2D barcode symbology. After a few hijinks with a loose ribbon cable and flaky PS/2 support on my computer I got the scanner working perfectly. I was even able to change its configuration by scanning barcodes from the manual displayed on my LCD (though I don’t know if it will work with glossy screens — mine is matte).

I’m planning on putting up a more complete summary of what I’ve found, but here are a few other things that caught my eye:

  • A solenoid-controlled proportional valve for small pneumatics or hydraulics.
  • A bag of large rubber grommets, one of which I cut up to replace the feet on a table lamp.
  • Three matched stepper motors.
  • A worm-gearbox connected to a large motor with integrated optical encoder.
  • A wide variety of IR LED/phototransistor gates.
  • A pile of 1.8V, 2.5V and 3.3V voltage regulators.

Stay tuned for pictures and more details on what I’m taking and what I’m going to do with it.

Heads Up: Migratory Internet Junk

If you haven’t heard of TGIMBOEJ (The Great Internet Migratory Box Of Electronics Junk), you should definitely check it out. The basic idea is that a box of random electronic junk gets shipped between makers and tinkerers, each of whom take something and contribute something to the box, and document what they end up doing.

To make a long story short, I was recently offered a chance to receive one of these migratory lending libraries, so expect to see something in this space about it soon.

Obama Buttons!

B4D3442D-F39D-49F1-A049-5996E9495255.jpgGuess what? MoveOn.Org is giving out FREE Obama buttons!

We’re giving away new Obama buttons for free, as part of a massive national visibility campaign. Want one? Click here:

After you’ve gotten yours, forward this email on to everyone you know so that they can get free Obama buttons too.

If hundreds of thousands of us wear these wherever we go, we’ll send a strong message that Barack Obama is the candidate with the buzz, momentum, excitement—and sincere support of regular folks across the country.

Everybody should pick one of these up and wear them!