Vocabulary IX Flashcards
Gradient
rate of change in a field value. It is also called the average slope.
Gradient = change in field value divided by
Change in horizontal distance
Isolines
lines of equal field values
Isotherms
lines of equal temperature values
Isobars
lines of equal pressure values
Mercator projections
are maps which are made by distorting the north and south poles making the sphere of the earth flat. Has parallel lines of longitude and latitude.
Conic projections
are maps which are made by putting a cone above a point with the bottom edge along a line of latitude. They are very accurate.
Quadrangles
7.5 minute map sections of the United States made by the US Geological Survey, named after a local physical feature.
Gnomonic projections
are maps which are round. Their outward edges fall along one of the great circles. They generally show distortion in size and distance.
Great circles
connect any two points along a circle where the Earth is able to be divided into equal halves.
Topographic maps
are maps which show the elevation of a particular area.
Contour lines
connect equal points of elevation either above or below sea level.
Index contour lines
are darkened lines which have the actual elevation labeled
Intermediate contour lines
are lighter lines which connect equal points of elevation but they are not labeled.
Geologic maps
are maps which show the different types of rocks in an area and the geologic time period in which the bedrock was formed.
Scale
shows the relationship of the distance on the map with the distance on the earth.
