Environmental Engineering Reference
In-Depth Information
TABLE 2.2
Guide to Map Scales
Scale
ft/in.
in./1000 ft
in./mile
miles/in.
m/in.
acres/in.
2
1:500
41.67
24.00
126.72
0.008
12.70
0.040
1:600
50.00
20.00
105.60
0.009
15.24
0.057
1:1000
83.33
12.00
63.36
0.016
25.40
0.159
1:1200
100.00
10.00
52.80
0.019
30.48
0.230
1:1500
125.00
8.00
42.24
0.024
38.10
0.359
1:2000
166.67
6.00
31.68
0.032
50.80
0.638
1:2400
200.00
5.00
26.40
0.038
60.96
0.918
1:2500
208.33
4.80
25.34
0.039
63.50
0.996
1:3000
250.00
4.00
21.12
0.047
76.20
1.435
1:4000
333.33
3.00
15.84
0.063
101.60
2.551
1:5000
416.67
2.40
12.67
0.079
127.00
3.986
1:6000
500.00
2.00
10.56
0.095
152.40
5.739
1:7920
660.00
1.515
8.00
0.125
201.17
10.000
1:8000
666.67
1.500
7.92
0.126
203.20
10.203
1:9600
800.00
1.250
6.60
0.152
243.84
14.692
1:10000
833.33
1.200
6.336
0.158
254.00
15.942
1:12000
1,000.00
1.000
5.280
0.189
304.80
22.957
1:15000
1,250.00
0.800
4.224
0.237
381.00
35.870
1:15840
1,320.00
0.758
4.000
0.250
402.34
40.000
1:19200
1,600.00
0.625
3.300
0.303
487.68
58.770
1:20000
1,666.67
0.600
3.168
0.316
508.00
63.769
1:21120
1,760.00
0.568
3.000
0.333
536.45
71.111
1:24000
2,000.00
0.500
2.40
0.379
609.60
91.827
1:25000
2,083.33
0.480
2.534
0.305
635.00
99.639
1:31680
2,640.00
0.379
2.000
0.500
804.67
160.000
1:48000
4,000.00
0.250
1.320
0.758
1,219.20
367.309
1:62500
5,208.33
0.192
1.014
0.986
1,587.50
622.744
1:63360
5,280.00
0.189
1.000
1.000
1,609.35
640.000
1:100000
8,333.33
0.120
0.634
1.578
2,540.00
1,594.225
1:125000
10,416.67
0.096
0.507
1.973
3,175.01
2,490.980
1:126720
10,560.00
0.095
0.500
2.000
3,218.69
2,560.000
1:250000
20,833.33
0.048
0.253
3.946
6,350.01
9,963.907
1:253440
21,120.00
0.047
0.250
4.000
6,437.39
10,244.202
1:500000
41,666.67
0.024
0.127
7.891
12,700.02
39,855.627
1:750000
62,500.00
0.016
0.084
11.837
19,050.04
89,675.161
1:1000000
83,333.33
0.012
0.063
15.783
25,400.05
159,422.507
Formula
Scale
12.000
63.360
Scale
ft/in.
(Scale)
2
12
Scale
Scale
63.360
0.3046
43,560
144
Bedrock geology maps
(Figure 2.2)
often provide only the geologic age; the rock types are
usually described in an accompanying text. There is a general correlation between geologic
age and rock type. The geologic time scale and the dominant rock types in North America
for the various time periods are given in
Appendix A.
The formations for a given period are
often similar in other continents. For the purpose of mapping, rocks are divided into for-
mations, series, systems, and groups. Formation is the basic unit; it has recognizable con-
tacts to enable tracing in the field and is large enough to be shown on the map. Series are
coordinate with epochs, systems with periods, and the largest division, groups, with eras.
Structural geology
may be shown on special maps or included on bedrock geology maps
using symbols that identify faults, folding, bedding, jointing, foliation, and cleavage. The
maps often include geologic columns and sections. The common symbols used to define
geologic structures are given in
Figure 6.3.
Surficial geology maps
depict shallow or surficial soil and rock types;
Figure 7.1
is a map
of the distribution of soils in the United States.
