mobile geo social

In other news, GeoMeme now measures real-time local trends based on both MySpace and Twitter content.

GeoMeme uses the new Real-Time Stream API from MySpace to tap into the flood of geo-located updates being posted by MySpace users all around the world.

MySpace content is mashed up with tweets from a number of mobile Twitter apps, and located onto a Google Map. Local trends are identified using semantic analysis services from Yahoo.

A couple of example GeoMemes generated by all this real-time geo-located content: Rihanna beats Lady Gaga in New York, and Avatar beats Hurt Locker in Los Angeles.

When hiring Engineers, I always look for evidence of pet projects, so recently I thought it was fair to create one of my own: GeoMeme, the fun way to measure and share real-time local twitter trends.

Visitors to GeoMeme choose a location on the map, and two search terms to compare. GeoMeme then measures and compares the number of matching tweets within the bounds of the map, based on public data from a number of mobile twitter apps.

As an example, GeoMeme can work out that ‘love’ beats ‘hate’ in Manhattan:

GeoMeme is a desktop web application and also a location-aware mobile web app for iPhone and Android phones.

Implementing the mobile version of GeoMeme as a web app has some advantages and disadvantages, compared to building native iPhone &/or Android applications.

Native apps are great because they currently offer the deepest integration to the full capability of the phone, for example using device APIs to access Contacts, the Camera Roll, an Accelerometer, or the GPS chip. For some applications, this deep device integration is essential and so a native application is beneficial.

On the other hand, emerging HTML5-based mobile browsers are aiming to standardise integration to such device APIs, starting with Geolocation APIs; meaning that location-aware mobile web apps are now becoming viable. Aligned with this development is the new version of the Google Maps API. v3 has been greatly simplified since v2, and is now optimized for use on mobile phones. Less is more.

The deciding factor for me choosing to build a mobile web app for GeoMeme rather than a native app was development speed. A mobile web app enjoys far greater code re-use from the desktop web version, and it is possible to push regular updates and improvements to users, without having to wait for appstore approval or for users to upgrade.

I believe this need for development speed is common among a good proportion of mobile apps that are still in ‘rapid iteration’ or ‘release early, release often’ mode, so this post is intended to share some of the techniques used in GeoMeme with developers wanting to build their own location-aware mobile web apps.

Let’s build an example location-aware mobile web app called ‘Here I Am!’, for the photographically challenged. The app will present some local photographs (from Panoramio) which can be shared with friends on Twitter or Facebook.

Where on earth is that mobile phone..?

The first job of a location-aware mobile app is to work out where on earth the mobile phone currently is. Unfortunately, at the time of writing, there is still no universally reliable and accurate solution for a mobile web app to detect the location of the mobile phone it is running on. However the following partial solutions can be combined to good effect:

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GeoMeme is a pet project of mine. It’s a web app, and also a mobile web app for iPhone and Android, that measures real-time local twitter trends.

Visitors to GeoMeme choose a location on the map, and two search terms to compare. GeoMeme then measures and compares the number of matching tweets within the bounds of the map, based on public data from a number of mobile twitter apps.

As an example, GeoMeme can work out that ‘District 9′ beats ‘Inglorious Basterds’ in Manhattan.

As well as offering users the normal pan and zoom controls to move the map around, GeoMeme also introduces an innovative geo-autocomplete control which is powered by the geocoder service from Google Maps v3 API and the new Static Maps v2 API.

This blog post shares some details of how the geo-autocomplete control works, and offers some code so you can build your own geo-autocomplete controls.

1. Based on a partial location typed by the user, obtain a list of possible matching locations:

If the user has already typed ‘San’ into a form field, we can obtain a list of possible matching locations by passing this partial location to the geocoder service from Google Maps v3 API, as follows:

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GeoMeme is a web app (and also a mobile web app for iPhone and Android) that I recently developed as a pet project. It measures real-time local twitter trends.

Visitors to GeoMeme choose a location on the map, and two search terms to compare. GeoMeme then measures and compares the number of matching tweets within the bounds of the map, based on public data from a number of mobile twitter apps.

As an example, GeoMeme can work out that beats in San Francisco:

A large amount of geo-data is generated by GeoMeme, and so arises a need shared by many geo apps: scalable, fast, and accurate spatial queries, used to select a subset of geo-data for display as markers on a map, or on Google Earth.

Google App Engine

Google App Engine is an obvious choice for hosting your geo app. The App Engine datastore is built on top of Google’s BigTable technology which scales very well, and is optimized for fast data retrieval. And it doesn’t cost the earth like some traditional GIS database solutions.

Inequality constraint

If you are coming from a background of relational databases, you might think the solution here would be to store the latitude and longitude of all your markers in a database table, and do a simple query to retrieve only those contained within the bounds of the map.

However, the flipside of being optimized for fast data retrieval is that BigTable only allows inequality filters on a single dimension, to avoid the burden of full table scans. For example, the following form of spatial query is not supported because it specifies inequality filters on both latitude and longitude dimensions:

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I am pleased to announce the launch of GeoMeme, the fun way to measure and share real-time local twitter trends.

I got thinking about this when a recent Los Angeles earthquake was being measured in tweets per second rather than using the Richter Scale.

Then came the Magnitwude Calculator as a standard way to measure the magnitude of Twitter trends.

[Then came twotspot.com but that domain name was just too damn rude, so it was quickly renamed to GeoMeme.]

What does GeoMeme do?

GeoMeme measures real-time local twitter trends.

Tweeps are located on the map using public data from a number of iPhone twitter apps. When twitter launches its geolocation API, that will be used to locate even more people on the map.

GeoMeme measures and compares how many people on the map are tweeting about each of your two search terms:

The ‘magnitude’ of each search term is equal to the number of unique people tweeting per hour per square kilometer, so it increases when more people are tweeting in a smaller area.

Example: if 100 different people in an area of 10km² have tweeted about ‘love’ in the last 2 hours, the magnitude is 5.0 (100 divided by 10 divided by 2).

So you can search for ‘love’ and ‘hate’ and GeoMeme works out which one “beats” the other with the higher magnitude.

The default search terms are and smiley faces which provides a good measure of local happiness, as an example.

Can I use my iPhone?

Sure, or your iPod Touch. Here’s the screenshot:

Give me an example!

Thanks to some early coverage on The Register, Mashable, and Google Maps Mania, and winning Mashup of the Day on ProgrammableWeb, we’re off to a flying start. I’m glad GeoMeme is hosted on Google App Engine for scalability.

Here’s a selection of the most popular GeoMemes so far:

• beats in New York City
• Mega Shark beats Giant Octopus in LA
• Snow Leopard beats Windows 7 in Cupertino
• bridge beats swimming in San Francisco Bay
• wtf beats ftw in Washington

How does it all work?

I will leave the details of how it all works to another post, stay tuned for that.