No, there are two visibly active vents.  But recent modelling by Icelandic scientist use a fissure as long as the line of points in OSM.  See here: https://www.vedur.is/media/uncategorized/Monitor-map-45x25-cm-MrLavaLoba-17-days-20210325.jpg
Here is a fairly recent 3D-model: https://www.icelandwonder.com/news/3d-model-geldingadalur-volcano-iceland/