Topographic Maps Reading and Interpreting Topo Maps Investigation and Experimentation (Standard 1h)
Sierra NevadaTopographic Maps Yosemite Valley is located within the Sierra Nevada Province. Its topography shows great diversity with many peaks, valleys and rivers.
Maps - Introduction Different maps show us different things. Road Map – Shows us how to get from one place to another. Shaded Relief MapShows us the shape of the land – mountains, valleys, rivers and lakes. Topographic Map Uses contour lines to show elevation.
Topographic Maps - Introduction Topography is the study and description of the shape of the land and surface features. Topographic Map: Shows the shape of the land by connecting points of the same elevation to form a line – contour line.
Topographic Maps - Contour Contour lines: An imaginary line that connect points of equal elevation. Contour interval: The vertical distance between contour lines. Index Contours: The heavier, wider contour line (usually every 5th line) that gives us the elevation above sea level.
Map Reading Activity: Topography Q: What is the contour interval for the map? 40 feet Q: What is the distance between each index contour? 200 feet
Topographic Map – Contour Properties • Closely spaced contour lines represent steep slopes • Widely spaced contour lines represent gentle slopes.
Topographic Map – Contour Properties Q: Approximately how tall is Able Hill? About 42 feet Q: Approximately how tall is Baker Hill? About 50 feet Q: Which hill is taller and by how much? Baker Hill, 8 feet Q: How many feet of elevation are there between contour lines? 10 feet Q: Are the contour lines closer together at Able Hill or Baker Hill? Baker Hill Q: Which mountain has steeper slopes? Baker Hill
Topographic Map – Contour Properties Contour lines form a V when crossing streams. The V always points upstream (Upstream is NE). Concentric circles of contour lines indicate a hilltop or mountain peak. Concentric circles of hachured contour lines indicate a closed depression.
Topographic Map - scale • Map scale expresses the relationship between the distance on the map to the true distance on the earth’s surface. • This is usually represented as a ratio 1:24,000 or a fraction 1/24,000. • 1:24,000 means that 1 unit on the map represents 24,000 of the same units of the earth. 1:250,000 Covers more area but in less detail. Note The town of Apollo (center) and the Kiskiminetas River. 1:100,000 Medium scaled map. Note the town of Apollo. You can see the streets and the Kiskiminetas in more detail. 1:24,000 The small scale shows the most detail. It covers less area but with much more detail. Note Apollo. You can see houses and buildings.
Topographic Map – Colors Blue – water features Green – woodlands Brown– contour lines Red – roads, urban areas Black – Man-made features