Here’s what Wikipedia says about Urban Sketchers
Urban Sketchers (USk) is a global community of artists that practice drawing on location in cities, towns and villages they live in or travel to. The Urban Sketchers movement was started on Flickr in 2007 by journalist Gabriel Campanario. The Urban Sketchers Manifesto has been translated into several languages.
The USk motto is “We show the world, one drawing at a time!”
Urban Sketchers is a diverse group of people united by a passion for sketching. Discussions, for example about supplies and materials, take place when sketchers meet in real life or virtually.
USk website: http://www.urbansketchers.org
Urban Sketchers has a manifesto which reads:
We draw on location, indoors or out, capturing what we see from direct observation.
Our drawings tell the story of our surroundings, the places we live and where we travel.
Our drawings are a record of time and place.
We are truthful to the scenes we witness.
We use any kind of media and cherish our individual styles.
We support each other and draw together.
We share our drawings online.
We show the world, one drawing at a time.