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dvucinich13
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3 classifications of maps
- planimetric-road maps, specific area maps, schematic maps
- topographic- contour maps, shaded relief maps
- orthophoto- satellite or aerial pictured maps
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US national accuracy standards
1947- required accuracy within a few cm.
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representative fraction
- 1:24,000 most common for topographic maps
- proportion of map distance to actual ground distance in like units
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graphic scale
- comparison of map distance to actual ground distance in different units
- determined by: ground distance/measured distance between two points on map
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cardinal directions, top of map
N is the top of the map. E S W
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declination
- difference between true north and magnetic north in relation to your location
- only necessary when navigating with a map
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Colors on topo map
- Black- cultural/ man made features and boundaries
- Blue- water features, ice
- Green- vegetation
- Brown- contour lines, relief features
- Red- main roads, boundaries, special features
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ICS display symbols
Black, Red, Blue, Orange, Green, Brown, Purple, Grey
- Black: control line, branches, divisions, segments, dozer line( black with X's)
- Red: fire origin, hazards, spot fire, active fire edge
- Blue: water sources, ICP, base, staging, repeater site
- Orange: projected fire expansion
- Green: vegetation
- Brown: contours, cuts and fills, relief features
- Purple: revised info
- Grey: developed areas
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Contour lines
connect points of equal elevation
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contour interval
ground distance between contour lines. usually 40 ft.
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contour index
every fifth line is bold
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V contour
streams point up stream
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U contour
ridges- u points down ridge
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M or W contour
stream confluences
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contour line are always to streams
perpendicular
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contour lines do not....
cross, fork, or touch, except overhanging cliffs
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closely,widely, and equally spaced contour lines
- -steep terrain
- -gradual/gentle terrain
- - uniform terrain
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slope is expressed in...
%
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slope- one percent slope
100% slope
how to calculate slope
- one percent slope= 1' of rise every 100' horizontal distance
- 100%= 45 degree 100' of rise over 100' horizontal
% slope= VDx100/HD
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aspect
direction a slope is facing
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how many chains in a mile
80
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acre in chains
10 sq chains
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estimating acreage
- area in ft/ 43560
- area in chains/ 10
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tools used to estimate acreage
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latitude lines
- run E-W parallel to equator
- equator is 0 degrees, poles are 90 degrees
- one degree= 60 mins= 69 miles
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longitude lines
- lines run N-S, converge at poles
- prime meridian is Greenwich, England
- one degree approximately 67 miles...varies
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public land survey system
- uniform method to describe and convey land titles( legal location)
- replaced meets and bounds system
- Mt. Diablo, Mt. Pierce, San Bernadino are base points for CA
- 31 initial points in lower 48 states each with base point and principal meridians
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township
- 6 miles apart, lines run E-W
- 4 townships between standard parallel
- Township north, Township south to describe
- 36 sections in each township
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Range
- 6 miles apart, lines run N-S
- 4 ranges between guide meridian
- described Range West, Range East
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azimuth
always read at index pointer
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