State of the Map 2019 the annual state of the map conference will be held on Heidelberg this year, on 21-23 September.
Call for presantations is now open and will be so until 25 april 2019.
Read the blog post from OSM foundation and fill the form if you want to apply: https://blog.openstreetmap.org/2019/02/28/sotm-2019-call-for-participations/
Also if you are unable to attend it without financial support, you can apply for a schoolarship:
Also Humanitarian OpenStreetMap Summit will be held there on 19-20 September.