Thanks for supporting our rich text editor app. As many of you know, Essay is no longer available in the App Store. The good news is that I have been working with Evernote to bring rich text editing to their fantastic application. This means you get all of the rich text editing you love paired with the strong organization and sync capabilities of Evernote, all for free.

Learn more about the new Evernote functionality at
http://blog.evernote.com/2011/08/22/the-big-evernote-for-ios-update/

Regards,
Dirk Holtwick

Essay is available now on the Apple AppStore.

Here is an appetizing video that explains the main features:

To get an idea of it I recommend to watch this lightning talk Marc-Andre Lemburg gave at the EuroPython 2009.

Update 2009-09-02:

African press is speaking about the start of the pilot phase:

• http://all​africa.com​/stories/2​0090828065​2.html
• http://new​s.myjoyonl​ine.com/bu​siness/200​808/19027.​asp

Twittori.com is our current project that adds geo tagging to Twitter messages. It is very easy to use and intends to bring a more useable geo dimension into the Twitter World.

Unlike other services this is done by a tiny URL that itself contains all geo location informations e.g. http://GE0.at/0MbEX8 which locates the Eiffel Tower in Paris. This is achieved by a modified ‘geohash’ algorithm (more on that at Wikipedia).

The second unique feature is that users can follow places in a similar way than they are used to follow users on Twitter. Therefore the earth is divided in discrete squares of about 0.25 square kilometers. You can keep updated by subscribing to a RSS Feed or visiting the web site.

The Website

The web site has been designed by Martin “Datendesigner” Jacobs. It aims to be clear and simple to use.

The iPhone App

The iPhone App is waiting to become approved for the App Store. It is very easy to use and provides a well defined user interface. A little demo on Twittori.com shows the details: http://www.twittori.com/content/iphone

The Technology

The Google App Engine is used for hosting. Therefore the server side code is written in Python. For the AJAX stuff we use Google Maps, Google Gears, jQuery, jQueryTools scrollable, jQuery mousewheel, prettyPhoto. The CSS is based on Blueprint CSS Framework.

The Shortlink

We use the short link to identify the location you refer to and to connect the tweet with the Twittori service. We do not use the domain http://www.twittori.com but the domain http://ge0.at just because it is shorter (minus 10 characters). The six characters that follow the domain name contain the whole geo location information. That means it is not done like tinyurl.com, bit.ly or is.gd do it by  adding a new reference to their database. Instead you can calculate the corresponding latitude and longitude of the position from the six characters itself. The following section describes how this is done.

FROM A TECHNICAL VIEW

Basically we use the Geohash algorithm for calculating our location hash. We just expanded this technique to use 64 characters in place of 32 characters. Here you can see the implementation in Javascript to calculate the latitude and longitude from the hash:

var BITS = [32, 16, 8, 4, 2, 1];
var BASE = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_";

function refine_interval(interval, cd, mask){
    if (cd & mask)
        interval[0] = (interval[0] + interval[1]) / 2;
    else
        interval[1] = (interval[0] + interval[1]) / 2;
}

function decodeGeoHash(geohash){
    var is_even = 1;
    var lat = [];
    var lon = [];
    lat[0] = -90.0;
    lat[1] = 90.0;
    lon[0] = -180.0;
    lon[1] = 180.0;
    lat_err = 90.0;
    lon_err = 180.0;

    for (i = 0; i < geohash.length; i++) {
        c = geohash.charAt(i);
        cd = BASE.indexOf(c);
        for (j = 0; j < 6; j++) {
            mask = BITS[j];
            if (is_even) {
                lon_err /= 2;
                refine_interval(lon, cd, mask);
            }
            else {
                lat_err /= 2;
                refine_interval(lat, cd, mask);
            }
            is_even = !is_even;
        }
    }
    lat[2] = (lat[0] + lat[1]) / 2;
    lon[2] = (lon[0] + lon[1]) / 2;

    return {
        lat: lat[2],
        lon: lon[2]
    };
}

I wrote a little demo to show this in action. Follow this link: http://www.twittori.com/geohash.html#0BOdWE