Besides making street-level imagery available to anyone, Mapillary also uses computer vision to automatically extract map data from images. You can use two types of data.
1) Object detections are instances of different objects that have been detected in images. Since Mapillary images are geotagged, you can get a dataset of image locations for a particular object that interests you, and use that as a filter to quickly find and look at all images where that object is present (learn more).
2) Map features entail different objects positioned on the map. If the same object has been detected in multiple geotagged images, we can use triangulation to estimate the location of the object (learn more). Mapillary has:
- Points—point features for 42 object classes
- Traffic signs—also point features but broken down to 1,500 different traffic sign classes
- Lines—line features for 19 object classes
Object detections and point features (including traffic signs) are available through Mapillary for Organizations. Create a Mapillary account and set up an organization to get a map data subscription. Note that line features are currently not available under a commercial license.
How the data is created
Mapillary’s computer vision technology automatically detects what kind of objects have been captured in images, such as buildings, cars, pedestrians, traffic signs, bicycle racks, and much more (altogether 97 object classes). This is based on a method called semantic segmentation—an algorithm is trained to detect and assign a category label to every pixel in the image.
Example of object detections in an image
Another part of our computer vision technology deals with 3D reconstruction of places from the images. By connecting object detection and 3D reconstruction, we can triangulate the location of an object that has been detected in several images. That way, we can estimate the location of that object in the real world and place it on the map as a map feature.
In mapping terminology, map features are divided into three categories based on how an object is represented on the map: as a point, a line, or a polygon. Mapillary generates map features that are either points or lines.
Example of map features generated for traffic signs
Our point features include 42 different objects plus 1,500 different types of traffic signs. They're available through subscription plans under a commercial license. Line features (19 different objects) are currently only available under the Open Database License (ODbL) license.
To clarify, traffic signs are also point features. But because Mapillary is able to distinguish between different subclasses of traffic signs, they're often brought out separately, e.g. in the interface of the Mapillary web.
We're able to detect more objects in images than those currently available as map features. A big part of the object detections (65 object classes) is also available through subscription plans under a commercial license.
Mapillary's map data offering, displayed in the web app