Panoramic view from Vista House, overlooking the Columbia River Gorge at Crown Point, Corbett Oregon, United States. This is an equirectangular panorama. The rail at the edge of the parking lot is approximately circular, and hence all parts of it are equidistant from Vista House, and roughly equidistant from the point of view of the photo, so it appears linear here. That is a good guide to the curvature of the panorama.