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7.5 minute quadrangle
cover land measuring 7.5 minutes of arc from north- south and from east-west. at a scale of 1:24000. covers from 49-70 square miles.
appears in the upper right corner. may be named after a prominent city, feature, or town. most of that feature must lie within the quadrangle for the quad to be named after it. the state name is also here.
appears in the upper right corner. refers to the mapped area in degrees, minutes, and seconds.
does not show the shape and elevation of the land but the horizontal orientation and natural and manmade (cultural) features.
in the lower right margin. shows the name of the quad, the abbreviation of the state, and the year of latest revision.
plant imprint note
located in lower right margin. includes the name of the government department responsible for making the map and the name and location of the printing plant. the location above is used of USGS maps.
( on 7.5 maps) expressed in two ways: a fixed ratio or direct proportional/ diagrammatic bar scales. both are found in the lower margin.
fine, curving brown lines. the same elevation. Depict the shape and elevation of the land.
the vertical difference between adjacent contour lines. this value is printed beneath the feet/ kilometer bars in the lower margin.
national map accuracy standards
in lower center margin. makes sure that a map complies with government standards. if this is not present then the map does not meet the standards.
nine equal parts of the map. they are numbered from left to right in three rows. do NOT confuse this term with section.
class 1 buildings
structures primarily meant for housing human activities. these are shown by a solid or crosshatch print.
class 2 buildings
NOT meant for housing human activities. depicted by an open outline or a single hatch, with the hatch running northeast- southwest (diagonal) direction.
show depressions or pits in the land shown by closed contours with right angle tick marks pointing inward.
shown on maps of flatter areas to show features less than the basic interval. shown as dashed or dotted lines.
cut and fill contours
shown conditions on large areas around roads that define the local terrain with less than a contour interval. shown by hachures along the contour.
perennial pond or stream
these bodies of water are always present except during major draughts. they are shown by solid blue lines or solid blue lines with light blue fill.
intermittent pond or stream
these contain water only during a certain part of the year. the streams are shown by blue dashes separated by three blue dots. the lakes are shown by a solid blue outline filled with light blue diagonal hatching. the ponds are shown by a dashed blue outline filled with light blue diagonal hatching.
rule of the v's
the phrase that refers to the shape that a contour line has when it passes through a stream. the point of the 'v' points upstream.
horizontal control station marks
marks for which latitude and longitude have been determined. on quad maps they are shown as black outlined triangles with a dot in the center or the same as above plus the letters 'BM' (meaning bench mark) and the elevation. on actual site it is a metal tablet or other permanent type marks.
vertical control station marks
marks the place where elevation has been determined. on USGS topo maps this is shown by a black 'x' and labeled 'BM' for bench mark. the elevation is written in black numbers. on actual ground they are metal tablets or other permanent marks.
less accurate than bench marks but more accurate than contour lines. Unless the locations are obvious, like a road intersection, these will be marked by small blacks 'x's with the elevation printed in black slanted type. (this is for topo maps) number values of spot elevations which have not been accurately surveyed are printed in brown.
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