Topographic maps are based on topographical surveys. Garmin offers different maps for purchase, including detailed road maps, topographic maps and nautical maps. This topographic map is called a retinotopic map. The database is part of a system that includes topographic map names and bibliographic references. A barometric altimeter, used along with a topographic map, can help to verify one's location. The eastern boundary of the plains is more climatic than topographic. The watershed transformation considers the gradient magnitude of an image as a topographic surface. Land Information New Zealand is the government agency responsible for providing up-to-date topographic mapping. Therefore, the Mars geoid is essentially the figure of Mars abstracted from its topographic features. Younger igneous rocks form spectacular topographic features. Irregular astigmatism is quantified by a vector calculation called topographic disparity. Mass wasting such as landslides further reduced topographic relief. It is one of the highest peaks in Europe in terms of topographic prominence. This is a list of mountain peaks ordered by their topographic prominence. The following mental exercise may illustrate the meaning of topographic prominence.