Observation device, in particular field glasses designed as binoculars or a monocular, having a fully automatic map-referenced location determination functionality, comprising • a camera having an objective lens and a camera sensor for recording an image of a terrain surrounding the camera as a camera image, • a data memory for storing program data and a digital terrain model, wherein the DTM contains at least parts of the surrounding terrain as spatial, digitally processable information, • a sensor system for the rough initial determination of a spatial location of the observation device, wherein the spatial location comprises an item of position information and/or an item of orientation information, • an analysis unit having data processing functionality, image data processing functionality, and sensor signal analysis functionality, configured for the purpose of □ carrying out a rough initial determination of the spatial location of the observation device by means of analysis of signals of the sensor system, and □ ascertaining, from the stored spatial information of the DTM, simulated image positions of terrain transitions potentially detectable by the camera, in relation to the initial roughly determined spatial location of the observation device, and • a display screen, characterized in that the analysis unit is configured for the purpose of • at the ascertained simulated image positions, the recorded camera image is automatically checked for a presence of a depiction of a terrain transition, wherein the initial roughly determined spatial location of the observation device and accordingly the ascertained simulated image positions of potentially detectable terrain transitions are virtually varied within defined tolerances, in particular based on a previously ascertained result of the automatic check, and • the automatic check is repeated in the scope of an optimization, in particular with variation of the respective virtual spatial location and the simulated image positions, and the spatial location of the observation device is established/determined as an optimization result based thereon. • a camera having an objective lens and a camera sensor for recording an image of a terrain surrounding the camera as a camera image, • a data memory for storing program data and a digital terrain model, wherein the DTM contains at least parts of the surrounding terrain as spatial, digitally processable information, • a sensor system for the rough initial determination of a spatial location of the observation device, wherein the spatial location comprises an item of position information and/or an item of orientation information, • an analysis unit having data processing functionality, image data processing functionality, and sensor signal analysis functionality, configured for the purpose of □ carrying out a rough initial determination of the spatial location of the observation device by means of analysis of signals of the sensor system, and □ ascertaining, from the stored spatial information of the DTM, simulated image positions of terrain transitions potentially detectable by the camera, in relation to the initial roughly determined spatial location of the observation device, and □ carrying out a rough initial determination of the spatial location of the observation device by means of analysis of signals of the sensor system, and □ ascertaining, from the stored spatial information of the DTM, simulated image positions of terrain transitions potentially detectable by the camera, in relation to the initial roughly determined spatial location of the observation device, and • a display screen, • at the ascertained simulated image positions, the recorded camera image is automatically checked for a presence of a depiction of a terrain transition, wherein the initial roughly determined spatial location of the observation device and accordingly the ascertained simulated image positions of potentially detectable terrain transitions are virtually varied within defined tolerances, in particular based on a previously ascertained result of the automatic check, and • the automatic check is repeated in the scope of an optimization, in particular with variation of the respective virtual spatial location and the simulated image positions, and the spatial location of the observation device is established/determined as an optimization result based thereon.