Not every data item in OpenStreetMap can have an immediate impact on the rendered map. But you can make every data item visible on a map and share the links or share the data, no matter how much the item is special interest. This is the purpose of Overpass API and Overpass Turbo. Our aim is to create special interest maps like this one for [historic street lamps](http://osmstreetlight.bplaced.net/#16/51.2339/6.7829), this one for [vehicle restrictions](http://maxheight.bplaced.net/overpass/map.html?zoom=14&lat=49.4&lon=8.68&layers=B0000000TFFTFFFFFFFF), or simply [all restaurants by cuisine](https://overpass-turbo.eu/s/I6z). An introduction to the Overpass API, to Overpass Turbo and the query language will be given. The aims are that the participants are afterwards able to filter for one for more tags, variants of tags, one or more keys, geographical regions, and combinations of such criteria. The Overpass API also supports to count objects, to dump them to GeoJSON, to retreive them in QGIS, in uMap, or a couple of [other downstream tools](https://dev.overpass-api.de/overpass-doc/en/targets/index.html). I will try my best to advance to these topics as well, but questions on the more basic issues have precedence. Thus the advanced topics are expected to rather go to an additional informal session if there are people interested in that. Please ensure that your are familar with the concepts of tags, nodes, ways, and relations, or read [an introduction here](https://dev.overpass-api.de/overpass-doc/en/preface/osm_data_model.html). You will benefit best from the workshop if you bring your own device with browser, internet access, and sufficiently large screen to view a map.