A computer-implemented method comprising: receiving, by a computing system, data generated by a camera and representing imagery that includes at least a portion of a physical real-world environment comprising the camera and a travelway; and determining, by the computing system and based at least in part on the data and a machine-learning model, a geographic orientation of the camera with respect to the travelway; wherein determining the geographic orientation of the camera with respect to the travelway comprises: determining a geographic location of the camera; selecting, based at least in part on the geographic location of the camera, the machine-learning model from amongst a plurality of different machine-learning models for determining geographic orientations of cameras with respect to travelways, the plurality of different machine-learning models being based at least in part on training data comprising imagery from different corresponding geographic regions, the machine-learning model being based at least in part on training data comprising imagery from a geographic region comprising the geographic location of the camera, the imagery from the geographic region not including imagery that comprises the travelway; determining, based at least in part on the machine-learning model, two possible geographic orientations of the camera with respect to the travelway, the two possible geographic orientations differing by one hundred and eighty degrees; and selecting, from amongst the two possible geographic orientations, the geographic orientation of the camera with respect to the travelway. receiving, by a computing system, data generated by a camera and representing imagery that includes at least a portion of a physical real-world environment comprising the camera and a travelway; and determining, by the computing system and based at least in part on the data and a machine-learning model, a geographic orientation of the camera with respect to the travelway; wherein determining the geographic orientation of the camera with respect to the travelway comprises: determining a geographic location of the camera; selecting, based at least in part on the geographic location of the camera, the machine-learning model from amongst a plurality of different machine-learning models for determining geographic orientations of cameras with respect to travelways, the plurality of different machine-learning models being based at least in part on training data comprising imagery from different corresponding geographic regions, the machine-learning model being based at least in part on training data comprising imagery from a geographic region comprising the geographic location of the camera, the imagery from the geographic region not including imagery that comprises the travelway; determining, based at least in part on the machine-learning model, two possible geographic orientations of the camera with respect to the travelway, the two possible geographic orientations differing by one hundred and eighty degrees; and selecting, from amongst the two possible geographic orientations, the geographic orientation of the camera with respect to the travelway. determining a geographic location of the camera; selecting, based at least in part on the geographic location of the camera, the machine-learning model from amongst a plurality of different machine-learning models for determining geographic orientations of cameras with respect to travelways, the plurality of different machine-learning models being based at least in part on training data comprising imagery from different corresponding geographic regions, the machine-learning model being based at least in part on training data comprising imagery from a geographic region comprising the geographic location of the camera, the imagery from the geographic region not including imagery that comprises the travelway; determining, based at least in part on the machine-learning model, two possible geographic orientations of the camera with respect to the travelway, the two possible geographic orientations differing by one hundred and eighty degrees; and selecting, from amongst the two possible geographic orientations, the geographic orientation of the camera with respect to the travelway.