Cartography The study of maps and map making

Types of Map Projections

Mercator Benefits: shows the whole world on one continuous map Distortions: areas near the poles Uses: shows true direction in straight lines

Gnomonic Made as if a sheet of paper was placed on one point on Earth’s surface (usually one of the poles). Benefits: shows polar regions accurately Distortions: land masses away from the center point Uses: planning ocean and air voyages

Polyconic Benefits: curved latitude and longitude lines and most landforms keep their true shape and size Distortions: areas away from the mid-latitudes Uses: Mapping large areas of land in mid-latitudes

Globe

Topographic Maps Shows the “lay of the land.” Shows elevations by using contour lines.

Uses for Topographic Maps City planners use them to plan a public works projects Engineers use them to create road projects Geologists use them in searching for coal, oil, and gas You can use them for any outdo

Features of a Topographic Map Legend or Key – explains each symbol used on the map Elevation – the height of a feature above sea level. Sea Level – found at zero elevation

Map Scale - tells you how the map’s features compare in size with Earth’s surface.

Quadrangles – the world map is cut into smaller sections called quadrangles which are made into large scale or small scale maps. 7 ½ minute map 15 minute map - large scale - small scale - more detail - less detail - smaller area - larger area 1:24,000 1:65,000

Large scale vs Small scale

Example of a Small Scale Map

Example of a large scale map

Contour Lines Contour lines connect points of equal elevation. Index Contour – every 5 th contour line is bold and labeled with the known elevation.

Contour Interval – the difference in elevation between two adjacent contour lines. The contour interval for this map is _______

Depression Contour – hachure marks are used to show a drop in elevation (such as a sink hole or quarry). Hachures always point toward the lower elevation.

The spacing of the contour lines identify Gentle slopes and Steep slopes. The closer the contour lines are to each other – the steeper the slope.

Mountains and Hills – many contour lines close together. Saddles – a dip between two or more peaks. A chain of saddles is a mountain range.

Contour Lines and Rivers - contour lines always form the shape of the letter “V” when crossing rivers or streams.

Topographic Profiles A profile enables you to “see” the features of a topographic map from a side view.

Match the Profiles to their correct Map Sections

Colors on Topographic Maps Contour Lines – brown Man-made features – black Water features – blue Vegetation – green False – Color Imaging – assigns different colors to different wavelengths of light. On a false-color image : vegetation = red water features = black

A False Color Image of planet Earth

Symbols on Topographic Maps Compass Rose –helps you to orient the map in the correct direction.

Common Symbols Used

Benchmark - identifies areas of exact known elevation. A marker will be on the ground at that location. On the map: BM1582 On the ground:

Spot Elevation – also identifies areas of exact known elevation. There will be no marker on the ground at that location. On the map: 462X (Yes, X marks the spot!)

Remote Sensing From Air – aircraft photographs called photogrammetry From Space – satellites relay images to computers

GIS Global Information System – uses remote sensed data to create maps using ArcGIS computer programs.

GPS Global Positioning System – a device that uses information from up to 24 satellites to identify a specific location. Geocaching – a scavenger hunt game played using a GPS