We introduce Flatlandia, a novel problem for visual localization of an image
from object detections composed of two specific tasks: i) Coarse Map
Localization: localizing a single image observing a set of objects in respect
to a 2D map of object landmarks; ii) Fine-grained 3DoF Localization: estimating
latitude, longitude, and orientation of the image within a 2D map. Solutions
for these new tasks exploit the wide availability of open urban maps annotated
with GPS locations of common objects (\eg via surveying or crowd-sourced). Such
maps are also more storage-friendly than standard large-scale 3D models often
used in visual localization while additionally being privacy-preserving. As
existing datasets are unsuited for the proposed problem, we provide the
Flatlandia dataset, designed for 3DoF visual localization in multiple urban
settings and based on crowd-sourced data from five European cities. We use the
Flatlandia dataset to validate the complexity of the proposed tasks