maps and photos - chapter 6 & 7 all maps have common elements scale legend coordinate system...

Maps and photos - Chapter 6 & 7

All maps have common elements

•Scale

•Legend

•Coordinate system

•Orientation info- directional system

Maps and photos - Chapter 6 & 7

All maps have common elements

•Scale

•Legend

•Coordinate system

•Orientation info- directional system

Quadrant system Quadrant system

Azimuth system Azimuth system

Directional information

0

9090

0

N

S

EW

0

90

180

270

Unless otherwise stated, North is always toward the top of the page on all printed maps

Map Scales

•Verbal- words used to convey map distance / real world distance equivalencies

•e.g., one inch equals four thousand feet

•Graphic- usually a bar or line with calibration marks that indicate map distance real / world distance equivalencies

•Fractional - the unitless numeric ratio of map distance to real world distance equivalencies

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

1:40,0001:40,000

Legend- a window that shows all the symbols used on the map, commonly includes scale, title, and orientation information

Coordinate systems

Latitude/ Longitude (LAT/LONG)- based on 360 degree circle coordinate system with Equator and Prime meridian as the index lines

Commonly given as decimal degrees (38.6466° N, 98.3456° W), degrees with decimal minutes (38° 36.32’ N, 98° 18.2’ W) or degrees minutes and seconds (38° 36’ 18” N, 98° 18’ 12” W)

Coordinate systems

Latitude/ Longitude (LAT/LONG)- based on 360 degree circle coordinate system with Equator and Prime meridian as the index lines

Commonly given as decimal degrees (38.6466° N, 98.3456° W), degrees with decimal minutes (38° 36.32’ N, 98° 18.2’ W) or degrees minutes and seconds (38° 36’ 18” N, 98° 18’ 12” W)

North

South

Coordinate systems

UTM- a coordinate system based on a 1000 meter grid with the center of of each Zone as the alignment point of the grid cells

UTM coordinates might read 13 T 0559760 E 4282176 N

Coordinate systems

Township Range a coordinate system based on a numeric grid

Isoline maps

The most common of these in the geologic community are Topographic contour lines that show lines of equal elevation above mean sea level (msl)

Other types of contours show...

Isothermal - lines of equal temperature

Isoseismal- lines of equal seismic shaking intensity

Isobaric- lines of equal pressure

Isopach- lines of equal thickness

Topographic maps

Contour lines represent vertical elevation with reference to sea level (zero elevation)

Contour intervals are 5, 10, 20, 50 or 100 foot intervals

Index contours are labeled and are thicker

Contour lines NEVER cross or touch- WHY?

They “V” or kink when they cross a stream channel, with the point of the “V” in the UPSTREAM direction

They can create closed shapes on the map

can represent either a hill or a depression

Frequently used to make topographic profiles

Topographic maps

Contour lines represent vertical elevation with reference to sea level (zero elevation)

Contour intervals are 5, 10, 20, 50 or 100 foot intervals

Index contours are labeled and are thicker

Contour lines NEVER cross or touch- WHY?

They “V” or kink when they cross a stream channel, with the point of the “V” in the UPSTREAM direction

They can create closed shapes on the map

can represent either a hill or a depression

Frequently used to make topographic profiles

Topographic profile & Vertical Exaggeration

VE= fractional Vertical Scale

fractional Horizontal scale

VE= fractional Vertical Scale

fractional Horizontal scale

1/240001/24000

1/633601/63360==

63360633602400024000

== 2.64X2.64X