Topographic Maps and Coordinate Systems

Topographic Maps •Field Quantity might include Field map A region in space in which a similar quantity can be measured at every point or location Quantity might include Temperature Barometric pressure Elevation Etc. Field map A map on which measurements are plotted

Isolines Isolines connect points of equal value on a field map Iso means same

Isobars Isobars Lines that measure areas of equal barometric pressure

Topographic Maps Topographic maps show the shape of Earth’s surface Isolines on a topographic map are known as contour lines Contour lines show points of equal elevation

Topographic Maps Contour lines showing points of equal elevation

Below this it also states: Dotted lines represent 10-foot contours Below this it also states: Dotted lines represent 10-foot contours. (Below that it states that the data for the contour lines was bases on information obtained in 1929.)(*) Here is an image of the bottom of the map. There is a lot of information located here, but for now take a look at the area below the graphical scales. (*) Below the scales it says the contour interval is 20 feet. (*)

Contour Lines: What is the elevation of the little unnamed hill just above it? Remember the purple line is the 1700 foot line. (*) Going up to the summit (blue dot) of the hill, the next INDEX CONTOUR line is the 1800 foot line (red line). (*) Finally, there is one more index contour line closer to the summit. This is the . foot contour line (black) (*) 1900 BUT, we are not yet quite to the summit. There are 3 normal contour lines. The next contour line would be the 1920, the next is the 1940 and the one closest to the summit is the 1960. (*) Summit So, the summit of this hill is a little over 1960 feet. But it is below 1980 – otherwise there would be another contour line. (*)

Contour Lines: While your looking at Squaw Peak, notice that the brown contour lines have different spacing. Where the contour lines are close together, there is a steeper slope. Where the contour lines are farther apart, the slope is more gentle. (*)

Contour Lines: One last thing about contour lines is that they “V” upstream when they cross a river drainage. Blue represents water features on topographic maps, and the line and three dot pattern of the streams on this map indicate an intermittent stream – sometimes it flows and sometimes it doesn’t. (*) Next, notice how the contour lines form a “V” and that the “V” points towards the top of Squaw Peak (higher elevation), The rule of thumb is that the “V’s” point upstream,(*)

In this illustration of North Mountain Park all the stream drainages will be highlighted in purple. It includes the blue stream lines as well as the unmarked drainage. What was done was to draw a line that connects the tips of the “V”s.

Let’s take another look at the information at the bottom of the map. ( This is the name of the map and when it was created. Photorevised means that the map was reevaluated in 1982 and that changes to the 1965 map were indicated in purple. Obviously, the map needs to be revised again. (*)

Let’s take a look at the scale next. (*) Let’s take another look at the information at the bottom of the map. (*) This is the location of the Sunnyslope Quadrangle with respect to the rest of the state of Arizona.

The top scale is called the fractional scale: Scale 1: 24000. (*) This simply means that an inch on the map is equivalent to 24000 inches on the surface of the Earth. OR 1mm on the map is equivalent to 24000 mm on the Earth’s surface. (*) The top scale is called the fractional scale: Scale 1: 24000. (*) One unit of ANYTHING on the map is equal to 24000 of those things on the Earth Surface. (*) Let’s take another look at the information at the bottom of the map. (*) This is the area of the two scales. (*)

Latitude and Longitude (Geographic)

Geographic Coordinates of Willow Springs, Missouri

Universal Transverse Mercator (UTM) 60 – 6º zones (60x6 = 360º) Units are in meters Coordinates are: Meters East of a zone line Meters north/south of equator

Universal Transverse Mercator (UTM)

Universal Transverse Mercator (UTM)

Scale Verbal Graphic (Bar Scale) Fractional/Ratio 1:4 1 map unit equals 4 real units 1:24,000 1 map unit equals 24,000 real units 1 inch on the map = 24,000 inches in real life or _____ feet

Map Scale