Category Archives: Geo

Choropleth of GeoTweets from India, Neighbours

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In an attempt to understand the average Indian tech consumer and his/her relationship with location based services, I decided to start off with the Twitter stream. Looking at geotagged tweets (tweets that contain the user’s current location, possibly from the GPS of the device used for tweeting) of about 3 weeks, it is clear that the big cities are where the majority of geotweets are coming from.

Here is a statewise choropleth map of geotweets. It also contains statistics for Nepal, Bhutan, Bangladesh and Sri Lanka:

http://ishan.chattopadhyaya.com/geotweets

A whopping 28% of all Indian geotweets are from Maharashtra (mainly from Mumbai). Karnataka and Tamil Nadu are runners up with close to 12% and 9% respectively. Credits for visualization go to OpenStreetMap and Leaflet.

EXIF is so 2002, we need new standards

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Exchangeable Image File Format, or EXIF as we popularly know it, is a specification for file formats of images, video, audio etc. files. The images and video that we see around us and click on our digital cameras or mobile phones contain EXIF tags that specify various information about the shooting conditions of the image, geolocation etc.

Unfortunately, the latest specifications, EXIF 2.2, were defined with almost no extensibility in mind. Common frustrations, from an open data lover or a community mappers’ point of view, are that it is not possible to (a) associate geolocation with each frame of a video, (b) associate accelerometer/gyroscope readings with the images/videos, (c) capture timezone information along with the timestamps, (d) associate additional data such as temperature, digital compass, wifi, cell tower data with images/videos. The whole list is far more than these few, but these are most glaring shortcomings from my point of view.

It is the collective responsibility of all online services like WIkimedia Commons, Flickr, Pinterest, Picasa, Facebook, Youtube etc. as well as camera and phone manufacturers to push for and collectively formulate a new version of the standard, so as to make sure the future generations don’t miss out on the conditions under which we shot, what we shot..