Map Accuracy

Negative
Scale

Map Scale

Contour Interval

Horizontal Accuracy

Vertical Accuracy

Camera Altitude
Above Ground Level

Forward Gain Per Negative 60% Overlap

Usable Width Mapping Strip 30% Side Lap

Area
Stereo Model

Area Full Negative

Feet

Miles

Feet

Miles

Acres

Sq. Miles

Acres

Sq. Miles

6 INCH FOCAL LENGTH CAMERA

1" = 200'

1" = 20' - 1" = 50'

0.5'

0.15'

1200'

720'

.136

1260'

.24

20.8

.03

74.4

.116

1" = 250'

1" = 30' - 1" = 50'

0.63'

0.22'

1560'

936'

.177

1638'

.31

35.2

.05

125.7

.196

1" = 330'

1" = 40' - 1" = 100'

0.83'

0.25'

1980'

1188'

.225

2079'

.39

56.7

.09

202.5

.316

1" = 500'

1" = 50' - 1" = 200'

1.25'

0.45'

3000'

1800'

.341

3150'

.60

130.16

.20

464.9

.726

1" = 660'

1" = 100' - 1" = 200'

1.63'

0.5'

3960'

2376'

.450

4158'

.79

226.8

.35

810.0

1.27

1" = 800'

1" = 200' - 1" = 400'

4800'

2880'

.545

5040'

.95

333.2

.52

1190.1

1.86

1" = 1000'

1" = 200' - 1" = 400'

2.5'

6000'

3600'

.682

6300'

1.19

520.7

.81

1859.5

2.91

1" = 1320'

1" = 200' - 1" = 400'

3.3'

2.5'

7920'

4752'

.900

8316'

1.58

907.2

1.42

3240.0

5.06

1" = 2000'

1" = 400 - 1" = 1000'

10'

12000'

7200'

1.36

12600'

2.39

2082.6

3.25

7438.0

11.62

NOTE: Negative scale determines horizontal and vertical accuracy. Map scales and contour intervals can be varied to suit specific project requirements. Topographic features may be omitted or added to all maps to accommodate specific requirements.
Standard Topographic Features Shown		National Mapping Standards Contours 90% of the elevations determined from the solid line contours shall have an accuracy of ½ the contour interval or better with respect to true elevation and the remaining 10% shall not be in error by more than one contour interval. In the areas where vegetation obscures the ground and the contours are shown as dashed lines, they shall be plott3ed as accurately as possible from the stereoscopic model. Spot Elevations 90% of all spot elevations placed on the maps shall have an accuracy of at least ¼ the contour interval, and the remaining 10% shall not be in error by more than ½ the contour interval. Planimeteric Features 90% of all planimeteric features which are well defined on the photographs shall be plotted within at least one fortieth of an inch of their true position at map scale. None of the features shall be misplaced by more than one twentieth on an inch.
1" = 50'	Buildings, roads, railroads, drainage features, bridges, culverts, fences, driveways, poles, sidewalks, individual trees, fire hydrants, manholes, catch basins, etc.
1" = 100'	Buildings, roads, railroads, drainage features, bridges, culverts, fences, driveways, poles and trees.
1" = 200'	Buildings, roads, railroads, drainage features, bridges, major fences, groups of trees.
1" = 400'	Major buildings, roads, railroads, identifiable bridges, major drainage features, timer areas.
NOTE:	Map scales, contour intervals and planimeteric detail can be varied to specific requirements. Where foliage or vegetation obscures the ground, contours will be shown as dashed lines, unless otherwise specified. (Normal accuracy no quarantined). 90% of the profile and cross section elevations will be within the listed accuracy where the ground is visible.

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