MAPPING AND CHARTING FROM THE AIR
(FIGS. 54 TO 82)
Mention has already been made (p. 56) of the experiment in map-making
carried out by the Army Air Service and the United States Geological
Survey at Schoolcraft, Mich. The results of that experiment and of
others of the sort are sufficient to establish the fact that the air
camera is destined to become a valuable addition to the map-maker’s
equipment. The extent to which it will be used depends, of course, upon
the degree to which its present imperfections are corrected and its
possibilities developed. The Board of Surveys and Maps of the United
States government has recently published the results of its study of air
photography for use in map-making.[6]
[Illustration: FIG. 54--View across the western end of Lake Erie,
looking in a northeasterly direction (see Fig. 55). Oblique photograph
taken from 18,000 feet above Port Clinton, Ohio, by Lieut. G. W.
Goddard, showing, in the foreground at the right, Catawba “Island,” a
part of the mainland, and, at the left, Put-in-Bay and the islands
around it. In the distance below the white clouds are a small island
(Middle Island) and a large one (Pelee Island). In the upper left-hand
corner is seen Point Pelee and the Canadian shore to the northeast of it
about 30 miles away. At Put-in-Bay was fought, September 10, 1813, the
Battle of Lake Erie, in which Commodore Perry defeated the British. The
monument commemorating this victory can be distinguished in the
photograph as a white shaft.
Although most vertical airplane photographs are in the nature of
large-scale maps, this view illustrates how a large area can be covered
in an oblique view taken at a high altitude--an area, when transformed,
of appreciable size even on a small-scale map, such as, for example,
Fig. 55.]
[Illustration: FIG. 55--Map of the western end of Lake Erie showing the
area covered within the angle of vision of Fig. 54. Scale, 1:1,400,000.
FIGS. 54 (upper) and 55 (lower). For explanation, see bottom of opposite
page.]
SCALE AND HORIZONTAL CONTROL OF VERTICAL PHOTOGRAPHS
The vertical photographs taken with an air camera are, of course, of the
order of large-scale maps.[7] For a lens of 6-inch focus the scale at an
elevation of 2,500 feet will be 1:5,000; at 5,000 feet, 1:10,000; and at
10,000 feet, 1:20,000.[8] Air mapping, therefore, lends itself best to
the production of such maps as engineering maps, city plans, topographic
maps, and coast charts. In all of these maps a degree of accuracy is
demanded that will give the exact location of all the features included
on the map and permit the precise measurement of distances between them.
To obtain such accuracy necessitates an elaborate system of control
stations as a basis on which the surveyor works out his triangulations
and traverses. In the United States these controls have been established
principally by the United States Coast and Geodetic Survey.[9] To
construct a map from air photographs, varying in scale and distorted as
they often are because of the impossibility of holding the plane at an
absolute level and because of the stretching or shrinkage of the
photographic paper, would require a great amount of triangulation and
traverse in order that the control might be sufficiently detailed to
permit the accurate mounting of the photographic prints. But, given
these controls, the air camera can, without further adaptation, supply
details that heretofore required the laborious processes of plane-table
mapping. The topographer can place the two-dimensional details from
photographs and then go into the field with only the contouring to be
done.
[Illustration: FIG. 56]
[Illustration: FIG. 57]
[Illustration: FIG. 58--Index map showing the location of the areas
shown on airplane photographs in this book within the Atlantic seaboard
of the northeastern United States, except those whose exact location is
unknown (Figs. 21, 23, 28, 29, and 77). Scale, 1:2,800,000.]
[Illustration: FIG. 59--An area where charting of the coast line is
difficult: Marshlands on Chesapeake Bay which are exposed at low tide
and submerged at high tide. Location: South of the mouth of the York
River, Virginia, between the estuaries of Poquoson River and Back River.
Scale, about 1:2,500.]
[Illustration: FIG. 60--Beach and bluff: Left shore of the York River
north-northwest of Gloucester Point, Va., showing a tied island (one of
the Mumfort Islands) and a narrow band of beach between the water and
the bluff, which is 20 to 50 feet above the water. The plain back of the
bluff is recognized by the checkered pattern made by the cultivated
fields. Scale, about 1:9,000.]
[Illustration: FIG. 61--A sandy beach with beach cusps forming the
extreme northwestern end of Sandy Hook, New Jersey, showing, at the
left, the end of the Hook surrounded by light-colored sand shading off
to shoals and bars; at the right, a broad belt of sand where a new point
is beginning to form; and, between them, six cusps arranged like saw
teeth. Note that a wave breaks into foam at the point of each cusp.
Scale, about 1:9,000.]
USE IN CITY MAPPING
In city mapping, even though time be taken to establish a very elaborate
system of controls, the air camera can accomplish in a few hours a task
of years by ordinary methods. In fact it is only by means of air
photographs that maps of a growing city can be kept at all up to date.
Paris was mapped with 800 plates in less than one day of actual flying.
Washington was completely mapped in two and a half hours with less than
200 exposures.[10] For the mosaic of Rochester, N. Y. (Fig. 56) 82
photographs were made in one hour and twenty minutes. There is no reason
why such a mosaic with an original survey or even a number of accurately
located points as a basis of control should not be sufficiently accurate
for all purposes.
USE IN REVISION OF EXISTING MAPS
Another immediate use of air photographs in mapping is in the correction
and revision of existing maps. So far as individual features are
concerned, the air photograph is an exact record of the area exposed to
its lens, and natural and artificial features are easily transferred
from the picture to the map. Its great value in the saving of time and
money has been demonstrated in the rapidly developing territory near Los
Angeles. In 1893 the Santa Monica quadrangle was surveyed, and houses,
roads, etc., as they existed at that time, are shown on the map. This
area was later built up and so changed that the map was practically
worthless. From information derived from air photographs the map was
revised in 1920 (Fig. 51). Evidence has already been given of the
efficiency of the air photograph in elaborating maps where the
importance of the region is not sufficient to warrant the expense of a
detailed survey of minor features, and in mapping areas inaccessible
from the ground.
[Illustration: FIG. 62--Beach cusps extended under water and showing the
interference of waves off the curved beach on the bay side north of
Beach Haven, N. J. Scale, about 1:3,000.]
[Illustration: FIG. 63--First stage in the formation of an inlet through
a barrier beach, where ocean waves during some storm, probably at high
tide, broke over the sand barrier 2 miles north of Beach Haven, N. J.,
and washed some of its sand into Little Egg Harbor. (For another good
example of wash-overs, see Fig. 68.) Scale, about 1:9,000.]
[Illustration: FIG. 64--A tidal delta in Shark River Inlet, Belmar, N.
J., as photographed from a height of 10,000 feet, showing shoals at the
left, which appear shadowy because they are under water, and the small
channels which radiate outward from the narrow inlet like the ribs of a
fan. They are the distributaries of this underwater delta. Scale, about
1:11,000.]
USE IN COAST CHARTING
[Illustration: FIG. 65--A tidal delta built up until it is partly above
water: Popes Creek, Virginia, on the right bank of the lower Potomac
River, 4 miles southeast of Colonial Beach, as seen obliquely from a
height of 4,000 feet at 3:30 P.M., August 31, 1920. The tidal currents
from the Potomac have built hook-shaped bars nearly across the outlet of
the creek, and the inflowing currents have built a delta from the mouth
of the creek upstream.]
It is fortunate for those engaged in the study of shore features and the
mapping of coasts that, being flat, shore features are particularly well
adapted to representation by air photographs, for on coasts exposed to
the wind and waves the channels, shoals and bars are continually
changing. Air photography offers a quick and convenient means of keeping
charts up to date. The intricacies of the water line in some places
makes accurate charting by the ordinary survey methods a slow, laborious
process. When bluffs or relatively steep slopes, like those of York
River, Virginia, near Gloucester Point, shown in Figure 60,
[Illustration: FIG. 66. (For explanation, see next page.)]
[Illustration: FIG. 66--A double tidal delta at Barnegat Inlet, New
Jersey, as photographed from a height of 10,000 feet. To the east
(right) the breaking waves and shadowy depths indicate the position of
shoals. West of the surf belt are the light-colored beach sand, shading
off from the conspicuous hook at the southern end of Island Beach into
underwater shoals and bars, and older surfaces made dark-colored by the
growth of plants. South of the hook are the inlet leading into Barnegat
Bay and the northern end of Long Beach, at the point of which stands a
lighthouse whose long shadow is to be seen across the beach sand. The
mottled appearance of the bay to the left is due to shoals slightly
submerged or perhaps exposed at low tide, where dark-colored drainage
lines appear, and shading off to deeper water, where the submerged land
forms have a shadowy appearance. The distribution of the shoals
indicates that this is a double tidal delta, an infacing part west of
the inlet and an ocean-facing part to the right. Scale, about 1:17,000.]
[Illustration: FIG. 67 FIG. 67--A tidal inlet through the barrier beach
south of Beach Haven, N. J., connecting the Atlantic Ocean to the right
(east) with Little Egg Harbor to the left. The beach sand south of the
inlet is little above water level and is frequently washed by waves,
which shift the sand and produce the clouded appearance of the sandy
surface. The light-colored ragged belt at the right is surf; the
continuous narrow belt, beach sand; the clouded areas, recently washed
wet or slightly submerged sand. (The ordinary tidal variation here is
4.2 feet.) This inlet does not appear on the 1914 edition of U. S. Coast
and Geodetic Survey Chart 1216, and sand hooks had little more than
begun to form then. Scale, about 1:14,000.]
[Illustration: FIG. 68. (For explanation see bottom of next page.)]
[Illustration: FIG. 68--Beach between Brigantine and Little Egg Inlets,
New Jersey, showing a variety of features characteristic of a wave-built
sand barrier. The upper (northern) part of the illustration shows
several places where waves have broken over the sand barrier and washed
the sand westward, where it was redeposited at the left in the quiet,
protected water. Farther south are older wash-overs, where the enclosed
bay is nearly filled with sand. At the left are numerous islands,
streams, and flats characteristic of the salt marshes west of the
barrier beach along the New Jersey coast. Scale, about 1:7,000.]
[Illustration: FIG. 69--A simple spit: Lower Cedar Point, Maryland, on
the left bank of the lower Potomac River, 6 miles north of Colonial
Beach, Va., as seen obliquely downward from a height of 4,000 feet. The
white line on either side of the point is sand at the foot of bluffs.
Houses and fields are seen at the left.]
occur along the shore, the water line varies little from year to year.
But on very low lands, like those along Chesapeake Bay south of the
mouth of York River, shown in Figure 59, the strand may migrate over a
broad belt between high and low tide. For this reason it is desirable
that photographs of areas affected by the tide be accompanied by a
record of the date and time of day at which the exposure was made, in
order that the height of the tide at the time of exposure can be
computed. As the shore on the Coast and Geodetic Survey charts denotes
the water line at high tide, a photograph taken at low tide might be
interpreted as indicating an error on the chart. Where the water
migrates over such a broad belt of sand or mud, the problems of
charting become very troublesome. Photographs of such areas could be
taken at both low and high tide, and from these the belt of daily
flooding could be charted.
[Illustration: FIG. 70--A hook, or recurved spit, south of Brigantine
Inlet, New Jersey, as photographed from a height of 10,000 feet, showing
the strong curving upstream characteristic of spits on this ocean-facing
coast. The growing end of the spit, resembling a lily bud, shows an
underwater extension beyond the light-colored beach sand. To be noted is
the filling in of the lagoon behind the reef and its pools and drainage
lines. This figure is practically a southern continuation of Fig. 68.
Scale, about 1:9.000.]
EXPERIMENTS BY THE UNITED STATES, FRENCH, AND OTHER COAST SURVEYS
The use of photographs in charting the coast line was tested by the
United States Coast and Geodetic Survey.[11] A flight was
[Illustration: FIG. 71--A hook, or recurved spit, showing interference
with natural growth: The northern end of Ocean City. N. J., as
photographed from a height of 10,000 feet. At the right (east) appears
the curved body of sand, light-colored where dried, darker-colored where
bathed by the waves and fringed by surf. To the left certain
“improvements” seem to have interfered with the natural growth of the
spit, and a small bay of shallow water has been enclosed by the
formation of a bay-mouth bar across the outlet to the north. Scale,
about 1:14,000.]
made over the coast of New Jersey by Captain A. W. Stevens of the United
States Army Air Service, March 20, 1920, in a plane equipped with a K-1
camera of 10-inch focal length, which makes negatives 18 by 24
centimeters in size. During the flight the camera was maintained at an
altitude of about 10,000 feet. The course was covered by 183 exposures
made at such intervals of time that the prints overlap. Unfortunately
the exposures were not sufficient to give all the details desired for
marsh and water areas, but prints were made on developing paper suitable
for showing extreme contrast. These were matched together and a
continuous picture obtained. A part
[Illustration: FIG. 72--New Point Comfort, a complex recurved spit at
the tip of the peninsula enclosed by the York and Rappahannock Rivers,
Virginia. A vertical view taken from an altitude of about 10,000 feet,
showing in order from right to left (east to west): the wavy surface of
Chesapeake Bay; a light-colored band of beach sand curving westward in a
compound hook made dark-colored in some places by trees and brush; a
shallow bay west of the beach in which may be seen shoals, channels, and
sand bars under water; and low-lying areas showing woodland and
cultivated fields. The photograph was taken at a time of day when
reflected light from the partly enclosed body of water was dispersed,
allowing the submerged forms to appear. Scale, about 1:12,000.]
[Illustration: FIG. 73--Lines of growth in a sand spit: Tucker Beach,
New Jersey, as photographed from a height of 10,000 feet, showing the
growth southward by successive ridges, which probably began as sand
bars, grew to be barriers by wave action, were heightened by wind-blown
sand, and finally were added to the main body of the spit by the final
filling of the enclosed lagoons. To the right (east) is the Atlantic
Ocean, showing waves and surf near the light-colored beach sand. Farther
to the left are the ridges of sand made dark-colored by vegetation,
bordered by light-colored beach sand on Little Egg Inlet, which appears
to the south and west. Scale, about 1:14,000.]
of this picture, greatly reduced, is reproduced as Figure 22. Several
characteristic shore and salt marsh features are illustrated by this
series of photographs, and these are reproduced in separate figures
together with illustrations of special features in other places.
[Illustration: FIG. 74--An island developing toward the stage of being
tied to the mainland by a double tombolo, or connecting bar: Napatree
Point, as photographed from a height of about 10,000 feet, connected to
the east by Napatree Beach with the mainland at Watch Hill, R. I., and
approaching connection to the north with the mainland near Stonington,
Conn. On the outer side of the tombolos underwater shoals and bars are
seen dimly at the right (south, Block Island Sound side) and more
clearly at the left (west, Fishers Island Sound), where the boat landing
is situated at the edge of a submerged shelf. The surf appears as a thin
white line, the beach sand as a narrow light-colored belt, and the
higher land as dark-colored areas on which houses and other structures
stand. Scale, about 1:24,000.]
The main features illustrated in detail, all of which are continually
liable to change, making the keeping of a map of the area at all up to
date impossible by ordinary means, are as follows: coast of low-lying
mainland (Fig. 60); mud or peat-covered beach (Fig. 59); sandy beach
(Fig. 63); barrier beach (Fig. 67); beach cusps (Figs. 61 and 62);
recurved spits or sand hooks (Fig. 70 and others); compound hook (Fig.
72); lines of growth in the development of hooks (Figs. 73); tombolos
and tied islands (Figs. 60 and 74).
[Illustration: FIG. 75--Oblique view of the mouth of Powells Creek,
Virginia, on the right bank of the lower Potomac River, 5 miles west of
the Naval Proving Grounds at Indian Head, showing at the left the inner
channel winding through the slightly submerged shoals and fading out
toward the right where the channel crosses the submerged terrace of the
Potomac.]
Another experiment was made by the Coast and Geodetic Survey off the
coast of Florida, where the water is clear, in an attempt to photograph
“the small coral heads and pinnacle rocks” which may be disastrous to
boats. The report states that the results were unsatisfactory and
concludes that airplane pictures are useful in “aerial photo-topography”
but not in
[Illustration: FIG. 76--Channels, shoals, and terraces in a drowned
river valley: Roberts Creek, 9 miles southeast of Yorktown, Va., an
estuary tributary to Chesapeake Bay. Under the water in the drowned
valley is seen the channel, “braided” in some places, and extending out
through sand bars to the deep water of Poquoson River shown at the top
(north) of the illustration. At the left the dark-colored forest area is
fringed with a narrow strip of white beach sand, then with a belt of
shallow water at the outer edge of which the waves form an irregular
white line, and beyond this with a belt which represents a submerged
terrace. Scale, about 1:14,000.]
[Illustration: FIG. 77--The underwater channel in Quantico Bay. Quantico
Creek is a tributary of the Potomac River entering from the Virginia
side, about 28 miles downstream from Washington. The “Bay” is the
widened part of the stream at its entrance into the Potomac, which is
entered by the tide. Forested land appears at the right and left, with
light-colored fields at the left. The space between the wooded areas is
occupied by shallow water, beneath which appears the relatively deep
channel, which forks after the manner of streams. The branching channel
is wholly under water and differs in some respects from the channel of a
normal stream. Among the more obvious peculiarities is the “fanning
out,” of the headwaters. Photograph taken from a height of about 18,000
feet. Scale, about 1:21,000.]
[Illustration: FIG. 78--Natural channels and shoals near Miami, Fla.: an
oblique view eastward to the ocean across Bear’s Cut, which is situated
between Biscayne Key and Virginia Key. Because of the greater depth of
water, the channels with a maximum depth of 17 feet appear darker than
the shoals. The photograph was taken at a height of 3,000 feet, April
20, 1918.]
[Illustration: FIG. 79--A dredged channel at Miami, Fla.: an oblique
photograph showing part of the city, the boat landing, the sandy beach,
and the shallow water, through which a straight ship channel has been
cut, which appears dark-colored in the illustration because of the
greater depth of water. The photograph was taken April 22, 1918, from 21
height of 3,000 feet.]
[Illustration: FIG. 80--A shoal in Hereford Inlet north of Wildwood, N.
J., as seen from a height of 10,000 feet. The breaking waves indicate
that the shoal is only slightly submerged. (Tidal variation is here
about 4 feet.) The sand spit north of the shoal, the south end of
Sevenmile Beach, like other spits of the New Jersey coast, is building
southward and may in time annex the shoal. Scale, about 1:13,000.]
[Illustration: FIG. 81--Sand bars at Cape Charles, Va. South of the town
at the right is the harbor, into which a tug-boat is towing a barge.
West of the town (left) is a belt of light-colored beach sand and sand
bars ending at the south against the breakwater, north of the harbor.
The sand bars appear somewhat dim because they were photographed through
water. They are under water 1 to 6 feet deep at low tide, or 4 to 9 feet
at high tide. Scale, about 1:6,000.]
“aerial photo-hydrography.”[12] On the other hand, Volmat reports the
successful use of air photography for similar purposes on the French
coast, where photographs of objects down to a depth of 17 meters (about
56 feet) were found useful in several ways--among others, the discovery
of points of rock which had
[Illustration: FIG. 82--Bars, channels, beaches, and marsh near Far
Rockaway, Long Island, N. Y., as photographed from a height of 7,000
feet at 11 A.M., September 15, 1920. In order from the bottom of the
picture upward are: East Rockaway Inlet with a shoal to the left and the
sand hook at the end of Long Beach to the right of it; the beach south
of Far Rockaway with streets and houses; a group of boats in the inlet
at the right of the beach; an area of salt marsh that is filling the
lagoon behind the barrier beach; and a small section of the village of
Far Rockaway. Scale, about 1:12,000.]
escaped attention during very detailed surveys. He states that with
proper plates and ray filters the presence of objects invisible to the
eye is revealed by the camera.[13] Similar use of air photographs has
been made by the English in charting reefs, shallows, and harbors.
Thomas says: “In 1917 aeroplane photography was successfully used for
charting the harbor of Rahbeg on the Arabian coast.”[14] It is a
well-known fact that, under proper conditions, objects submerged to a
considerable depth under clear water can be seen from points high above
the surface. During the war, submarines were detected and followed by
observers in airplanes, and sunken vessels, mines, and other submerged
objects have been located by observation from the air. Illustrations in
this paper show the possibility of using this method of observation, to
some extent at least, in detecting and mapping shoals, channels, and
other features under water.
Photographs of channels like those of the Potomac River and its
tributaries will be commercially as well as scientifically valuable. The
deep-water channel of the Potomac is well known and has been charted;
but very little is known of many of the small tributary channels, such
as that of Powells Creek (Fig. 75). Where the channels are not well
known, such a photograph could be used to advantage in avoiding the
shoals, and, by surveyors, first in exploratory work and later as a
general guide in charting. Small boats entering this channel could use
the photographs either for the original location of the deep channel in
case no chart were available or for detecting changes in its course
after the chart was made. For uncharted channels, like those of many of
the tributaries of the Potomac River, air photography furnishes a quick
and accurate means of location.
No amount of sounding, charting, or description could produce so
accurate a mental picture of a drowned valley as that produced by Figure
76. In Figures 78 and 79, both of which were taken near Miami, Florida,
is illustrated the difference in appearance between natural and
artificial channels. The straightaway course and regular outlines of the
dredged channel contrast sharply with the winding course and merging
outlines of the natural channel. To the student of physiography and
earth history the photographs furnish a means of observation of a
definiteness heretofore quite unthought-of. On them the actual shape of
the channels, submerged terraces, and drowned land forms are shown in
detail.
IMPROVEMENTS UNDER WAY POINT TO PROMISING OUTLOOK FOR AIRPLANE
PHOTOGRAPHY
There is, however, need of careful research to determine the conditions
under which the best results can be obtained. The height and time of day
for exposures with a certain lens, the emulsion and kind of ray filter
best suited under certain conditions, the effect of light as it enters
and emerges from the water, and the effect of polarization are subjects
demanding consideration. Chief among the experiments now under way is
the determination of the kind of emulsion and ray filter or color screen
that will give the best results. It is a demonstrated fact that, with an
emulsion sensitive to red light, objects in the air invisible to the eye
because of intervening haze can be photographed through a red filter. It
is possible that water can be penetrated in the same way and that
filters of other colors will prove advantageous.
Certainly, the air photograph is only in its infancy--but an infancy
full of promise. As a means of securing new and advantageous views of
subjects of interest, it is not only entertaining but scientifically
and commercially valuable. As an aid in mapping it can, even in its
present stage of development, serve an important purpose by supplying
accurate knowledge of otherwise inaccessible regions, by furnishing
details that are valuable but expensive to obtain, and by permitting the
frequent and inexpensive revision of existing maps.
INDEX
Accuracy, 1, 74
Acknowledgments, viii, xi
Aerial photo-hydrography, 99
Aerial photo-topography, 93
Air photographs, how to read, 4;
improvements under way, 102;
oblique and vertical, 1;
value in coast charting, 93, 99, 101
Air photography, application, ix;
development, ix;
elements to be recorded, 2;
outlook, 102
Air Services, co-operation, xi
Aircraft, x
Airplane photography. _See_ Air photography
Aliso Creek, California, 68
Amundsen, Roald, 71
Anacostia flats, D. C., 12
Anacostia River, 13, 22 (ill.);
land along, mosaic photograph, opp. 32 (Fig. 13)
Animal trails, 29, 39
Annapolis, 7. _See also_ United States Naval Academy
Arabian coast, 101
Architects, 7, 11
Architecture, 11
Arizona, southern, 71
Arroyos, 61, 65 (ill.)
Atlantic City, N. J., 32 (ill.)
Atlantic Coastal Plain, 27;
meandering streams, 50;
salt marsh areas, 32 (ill.);
submarine land forms, 45
Atlantic Ocean, waves and surf, 91 (ill.)
Back River, Virginia, 76
Bagley, J. W., xii, 74
Baltimore and Annapolis Railroad bridge, 9 (ill.), 10
Barnegat Bay, 85
Barnegat Inlet, 84 (ill.), 85
Barrier beaches, 41;
between Brigantine and Little Egg Inlets, New Jersey, 86 (ill.);
cities and surroundings, 32 (ill.);
inlet formation through, 81 (ill.);
Long Branch, N. J., 18 (ill.);
tidal inlet through, Beach Haven, N. J., 85 (ill.).
_See also_ Beaches
Beach Haven, N. J., cusps, 80 (ill.);
inlet formation through barrier beach, 81 (ill.);
tidal inlet, 85 (ill.)
Beaches, bluff and beach on shore of York River, 77 (ill.);
cusps near Beach Haven, 80 (ill.);
Far Rockaway, Long Island, 100 (ill.);
sandy, with cusps--Sandy Hook, 78 (ill.).
_See also_ Barrier beaches
Bear’s Cut, Florida coast, 96 (ill.)
Belmar, N. J., tidal delta, 82 (ill.)
Benning, Camp, opp. 26, opp. 50
Benning, D. C., 13, 22 (ill.)
Benning Road, 13
Benning Road Bridge, opp. 22 (ill. and map)
Bidwell, Lake, California, 62 (ill.), 63 (map)
Bluffs, 83;
beach and bluff on shore of York River, 77 (ill.)
Board of Surveys and Maps, 72
Boundary disputes, 26;
Texas-Oklahoma, 51 (ill.)
Braided channels, 50, 51 (ill.)
Brigantine Inlet, New Jersey, 86 (ill.), 87;
recurved spit, 88 (ill.)
Bridges, 11;
Baltimore and Annapolis Railroad, 9 (ill.), 10;
Benning Road, opp. 22 (ill. and map);
Hell Gate, 11, 15 (ill.);
Pennsylvania Avenue, opp. 22 (ill. and map)
Bronx Borough, Port Morris section, 15 (ill.)
Bronx Kill, 15 (ill.)
Brooks, A. H., 69, 71
Buildings, construction records, 11;
pictures from a new angle, 7
Calabasas, Cal., topographic sheet, 65
Cameras, adaptation, 2;
automatic data records, 2;
construction experiments, 35;
Eastman mapping, recording symbols, 2, 3 (ill.);
faithfulness, 23, 26;
human eye and, 5, 101;
panoramic, xii;
stereoscopic, 6;
use, x;
use in map-making, 72;
value in coast charting, 93, 99, 101
Camouflage, 5, 6
Camp Benning, Ga., opp. 26, opp. 50
Canyons, 57;
Pecos River, 70 (ill.);
Santa Monica Mountains, 66 (ill.), 67 (map)
Cape Charles, Virginia, 43;
sand bars, 99 (ill.)
Capitol, National, frontispiece, 7
Catawba “Island,” Ohio, 72, 73 (ill. and map)
Channels, Far Rockaway, Long Island, 100 (ill.);
Miami, Fla, 96 (ill.), 97 (ill.), 102;
Potomac River, tributary, 101;
underwater, 93 (ill.), 94. (ill.), 95 (ill.)
Chanute, Octave, ix
Charting, 72;
coast, 83, 88
Chattahoochee River, opp. 50 (ill. and map)
Cherry Point, Virginia, 46 (ill.), 47 (map)
Chesapeake Bay, xi;
Lambs Creek on, 48 (ill.);
low lands along, 87;
marshlands difficult to chart, 76 (ill.);
wavy surface, 90 (ill.).
Cinder Cone, California, 57, 62 (ill.), 63 (map);
top, 64 (ill.)
City geography, 17 (ill.), opp. 26, 54 (ill.), opp. 74, 79
City planners, 1, 11
City planning, 12 (ill.);
Columbus, Ga., opp. 26 (ill. and map)
Clouds Rest, California, 60 (ill.)
Coast Charting, 83, 88
Coast surveys, experiments in mapping in United States, France, etc., 88
Coastal mud flats. _See_ Mud flats
Colonial Beach, Va., 83, 87
Color screen, 102
Columbus, Ga., opp. 26 (ill. and map);
meanders near, 50, opp. 50 (ill. and map)
Columbus, Ga.-Ala., topographic sheet, opp. 50
Construction records, 11
Controls, 74
Coral islands, 93
Corona, Cal., topographic sheet, 68
Corsons Inlet, New Jersey, 28 (ill.)
Cousaic Marsh, Virginia, 34 (ill.), 35 (map);
details, 31 (ill.)
Craters, 27, 57;
Cinder Cone, California, 62 (ill.), 63 (map), 64 (ill.)
Cusps, Beach Haven, New Jersey, 80 (ill.);
Sandy Hook, 78 (ill.)
Dayton, Ohio, 56
Deanewood, D. C., 13
Deltas, underwater, 33 (ill.), 45, 82 (ill.), 83 (ill.), 84 (ill.), 85 (ill.)
Depressions and elevations, interpreting, 4, 5
District of Columbia, Anacostia flats, 12
Drainage systems, 27;
Lee Marsh, Virginia, 30 (ill.).
_See also_ Marsh drainage
Drowned topography, 45;
terraces at mouth of Piankatank River, 46 (ills.);
valley--Lambs Creek, Virginia, 48 (ill.);
valley--Roberts Creek, Virginia, 94 (ill.), 102
East Rockaway Inlet, Long Island, 100 (ill.)
Eastern Shore of Virginia, 41;
mud-flat area, stream system, 42 (ill.), 43 (ill.)
Eastman mapping camera, opp. 74;
recording symbols, 2, 3 (ill.)
El Capitan, 60 (ill.)
Elevations and depressions, interpreting, 4, 5
Ellipse, Washington, D. C., 16 (ill.)
Eltham Marsh, Virginia, 36 (ill.), 37 (map), 39
Emulsions, 102
Engineering, 11;
projects covering large areas, 12, opp. 22 (ill. and map)
Erie, Lake, 72, 73 (ill. and map)
Erosion, headward, 57, 65 (ill.), 68 (ill.)
Everglades, 27
Exploration, 71
Exposure, 102
Eye versus camera, 5, 101
Far Rockaway, Long Island, 100 (ill.)
Filters, 102
Fishing Bay, Virginia, 46 (ill.), 47 (map)
Flats. _See_ Mud flats
Flood plain, 33 (ill.)
Florida coast, channels and shoals near Miami, 96 (ill.), 97 (ill.), 102;
coral heads and pinnacle rocks, 93
Flowerfield, Mich., 52 (ill.), 53 (map)
Forests, 23
Gardens, 12
Genesee River, opp. 74 (ill. and map)
Geologic maps, 69
Geology, 69
Glacial drift plain, 52 (ill.) 55
Glaciers, 57;
glacial gorge, Mt. Shasta, 59 (ill.);
Mt. Shasta, 58 (ill.)
Gloucester Point, Va., 77, 83
Goddard, G. W., 72
Gorges, 57, 61;
Genesee River, opp. 74. (ill. and map);
glacial gorge on Mt. Shasta, 59 (ill.);
San Joaquin Hills, California, 68 (ill.);
Yosemite Valley, 60 (ill.)
Grand Trunk Railway, near Schoolcraft, Mich., 56 (ill.)
Great Plains, 50;
river channel--Red River, 51 (ill.)
Gwynn Island, Virginia, 46 (ill.), 47 (map)
Half Dome, 60 (ill.)
Hampton, Va., small stream near, 33 (ill.)
Headward erosion, 57, 65 (ill.), 68 (ill.)
Hell Gate Bridge, 11, 15 (ill.)
Hereford Inlet, New Jersey, 98 (ill.)
Hill Marsh, Virginia, 34 (ill.), 35 (map), 38
Hooks. _See under_ Spits
Hotlum Glacier, Mt. Shasta, 58 (ill.), 59
Hudson River and West Point, 8 (ill.)
Ice cap, 57
Inclinometer, 2, 3 (ill.)
Index map showing areas photographed, 75
Inlets, formation through barrier beach, 81 (ill.);
Hereford Inlet, New Jersey, 98 (ill.);
River, New Jersey, 82 (ill.);
tidal--Beach Haven, N. J., 85 (ill.)
Introduction, ix
Iroquois, Lake, opp. 74
Islands, tied, 77 (ill.);
at Napatree Point, Rhode Island, 92 (ill.)
Ives, H. E., 6, 79
James River and Mulberry Island, 24 (ill.), 25 (map)
Jones, E. Lester, 74, 88
Jones, John Paul, 7;
mausoleum, 9 (ill.)
Kenilworth, D. C., 13
Kettleholes, 52 (ill.), 53 (map), 55, 56 (ill.)
Kilmarnock, Va., topographic sheet, 47
Lambs Creek, Virginia, 48 (ill.)
Land forms, submerged, 45
Landscape gardeners, 1, 11
Landscape gardening, 11, 12 (ill.), 13 (ill.);
Long Branch, N. J., 18 (ill.)
Langley, S. P., ix
Langley Field, xi
Lassen Peak, 57, 62 (ill.), 63 (map)
Lassen Peak, Cal., topographic sheet, 63
Lava, 62
Lee, Robert E., statue, 12 (ill.)
Lee Marsh, Virginia, 36 (ill.);
details, 30 (ill.)
Library of Congress, 7
Little Egg Harbor, New Jersey, 81, 85
Little Egg Inlet, New Jersey, 86 (ill.), 87, 91 (ill.)
Little Hell Gate, 15 (ill.)
Long Beach, Long Island, 100 (ill.)
Long Beach, New Jersey, 84 (ill.), 85
Long Branch, N. J., part, showing barrier beach development, 18 (ill.)
Long Island, East Rockaway Inlet, 100 (ill.);
Far Rockaway bars, channels, beaches, and marsh, 100 (ill.);
Rockaway Beach, 11, 17 (ill.);
Hell Gate Bridge to, 15 (ill.)
Los Angeles, 79;
map of region between Santa Monica and, 67
Lower Cedar Point, Maryland, 87 (ill.)
Ludlam Beach, New Jersey, 28 (ill.)
Map, index of photographed areas, 75
Mapping, city, 79;
from the air, 72
Mapping camera, opp. 22;
experiment with, 53, 56
Maps, air mapping and, 74;
air photograph adjustment, 35;
use of air photographs in revising, 79
Marsh drainage, 27, 29
Marshes, 27;
Chesapeake Bay, difficult to chart, 76 (ill.);
details of drainage, 30 (ill.);
details of frequently submerged, 31 (ill.);
Far Rockaway, Long Island, 100 (ill.);
salt marsh areas of coastal plain, 32 (ill.);
salt marsh features, 92;
stream development in tidal marsh, 28 (ill.)
Mathews, Va., topographic sheet, 47
Mattaponi River, 29, 36, 38
Meanders, 33 (ill.), 38;
abandoned, 50;
Chattahoochee River, opp. 50 (ill. and map);
marsh, 27
Menoher, C. T., xi
Mexican border, 71
Miami, Fla, channels and shoals, 96 (ill.), 102;
dredged channel, 97 (ill.), 102
Michigan, glacial drift plain, 52 (ill.), 53 (map)
Military Academy. _See_ United States Military Academy
Military observation, 4, 6
Mjöberg, Eric, 71
Monument Avenue, Richmond, Va., 12 (ill.)
Moraines, 52 (ill.), 53 (map), 55, 57;
Mt. Shasta, 59 (ill.)
Mosaics, 12, 20, 22 (ill.);
Anacostia River, D. C., land along, opp. 22 (Fig. 13);
Columbus, Ga., opp. 26 (Fig. 17);
Mulberry Island, Virginia, 24 (ill.);
Rochester, N. Y., opp. 74 (ill. and map)
Mountains, 22, 27;
features, 57;
of volcanic origin--Cinder Cone, etc., California, 62 (ill.), 63 (map)
Mud flats, 36;
coastal, 41;
stream channels and, 42 (ill.), 43 (ill.)
Mulberry Island, Virginia, 24 (ill.), 25 (map)
Mumfort Islands, Virginia, 77
Muskrats, 29, 39
Napatree Point, Rhode Island, 92 (ill.)
Naval Academy. _See_ United States Naval Academy
New angles, 7
New Guinea, 7
New Kent, Va., topographic sheet, 27, 35, 37
New Point Comfort, spit, 90 (ill.)
New York Connecting Railroad Bridge. _See_ Hell Gate Bridge
New York Harbor, xi
Newport News, Va., xi, 11;
shipyards, 14 (ill.)
Oblique photographs, 1
Ocean City, N. J., 32 (ill.);
hook, 89 (ill.)
Oil, prospecting for, 71
Ores, 69
Orientation, 61
Oxbows, 33 (ill.), 50
Pamunkey River, 29, 36, 38;
Cousaic Marsh, 31 (ill.);
Eltham Marsh, 36 (ill.), 37 (map):
marshes, 27;
Sweet Hall Marsh, 34 (ill.), 35 (map)
Panchromatic film, opp. 74
Paris, mapping, 79
Pecos River, 70 (ill.)
Pennsylvania Avenue Bridge, 13, opp. 22 (ill. and map)
Perry, Commodore, 72
Photographs, mosaic. _See_ Mosaics
Photography, airplane. _See_ Air photography
Piankatank River, Virginia, drowned terraces at mouth, 46 (ills.)
Pictures from new angles, 7
Plains, glacial drift, 55;
glacial drift, Michigan, 52 (ill.), 53 (map);
photographing from the air, 50
Popes Creek, Virginia, 83 (ill.)
Poquoson River, Virginia, 76, 94 (ill.)
Port Clinton, Ohio, 72, 73 (ill. and map)
Potomac Park, Washington, D. C., 16 (ill.)
Potomac River, xi, 16 (ill.);
channels, tributary, 101;
Lower Cedar Point, spit, 87 (ill.);
Popes Creek and, 83 (ill.);
Powells Creek and, 93 (ill.);
Quantico Creek and, 95
Potter, Lieutenant, opp. 74
Powells Creek, Virginia, 93 (ill.), 101
Put-in-Bay, 72, 73 (ill. and map)
Quantico Bay, 95 (ill.)
Quantico Creek, 95 (ill.)
Rahbeg, Arabia, 101
Railroads, 23
Randalls Island, 15 (ill.)
Ray filter, 102
Reconnaissance work, 69, 71
Red River, Texas-Oklahoma, 50, 51 (ill.)
Relief, means for showing, 5;
representation on maps, 66
Revision of maps, 79
Richmond, Va., Monument Ave., etc., 12 (ill.)
Rivers, 22;
Plains--Red River, 50;
miniature system, 33 (ill.)
Roads, 23
Roberts Creek, Virginia, 94 (ill.)
Rochester, N. Y., 2, opp. 74 (ill. and map)
Rochester, N. Y., topographic sheet, opp. 74
Rockaway Beach, Long Island, 11;
part, showing development, 17 (ill.)
Rocks, Florida coast experiment, 93;
sedimentary, 69, 70 (ill.);
study of, 69
Royal Arches, California, 60 (ill.)
San Joaquin Hills, California, 68 (ill.)
Sand bars, 45, 46 (ill.);
Cape Charles, Virginia, 99 (ill.);
Far Rockaway, Long Island, 100 (ill.)
Sandy Hook, N. J., 78 (ill.)
Santa Monica, Cal., 65, 66;
map of region between Los Angeles and, 67
Santa Monica Mountains, 57, 66 (ill.), 67 (map)
Santa Monica, Cal., topographic sheet, 67, 79
Scale in vertical photographs, viii, 74
Schoolcraft, Mich., 54 (ill.), 55 (map), 56, 72;
kettleholes near, 56 (ill.)
Schoolcraft, Mich., topographic sheet, 53, 55
Seashore, 22
Sedge grass, 29, 30, 38
Sentinel Rock, 60 (ill.)
Sepulveda Canyon, California, 66 (ill.), 67 (map)
Sevenmile Beach, New Jersey, spit and shoal, 98 (ill.)
Severn River, Virginia, 7, 9 (ill.)
Shadows, 5, 61
Shark River Inlet, New Jersey, 82 (ill.)
Shasta, Mt., 57, 58 (ill.);
glacial gorge on, 59 (ill.)
Shipyards, 11;
Newport News, 14 (ill.)
Shoals, 45, 84 (ill.), 85, 94 (ill.);
Hereford Inlet, New Jersey, 98 (ill.);
Miami, Fla., 96 (ill.), 97 (ill.), 102
Shore features, 83
Shrubbery, 13 (ill.)
Sierra Nevada Mountains, Cal., 62 (ill.), 63 (map)
Silt, 29, 36, 39
Simi Hills, California, 65 (ill.)
Simons, J. W., Jr., xi
Sky, cloudy and overcast, 49
Spa Creek, Maryland, 7, 9 (ill.)
Spits, lines of growth, Tucker Beach, New Jersey, 91 (ill.);
recurved, 88 (ill.), 89 (ill.), 90 (ill.);
Sevenmile Beach, New Jersey, 98 (ill.);
simple spit, 87 (ill.)
State-War-Navy Building, Washington, D. C., 16 (ill.)
Stereoscopic camera, 6
Stevens, A. W., opp. 74, 89
Stone Canyon, California, 66 (ill.), 67 (map)
Stonington, Conn., 92
Stove Point Neck, Virginia, 46 (ill.), 47 (map)
Stream channels and mud flats, 41, 42 (ill.)
Streams, development in tidal marsh, 28 (ill.)
_See also_ Rivers
Submarine geography, 45
Submarines, 101
Submerged land forms, 45
Submerged objects, detection, 101
Sunken mines, 101
Sunlight, 49
Surface, general aspects as seen from the air, 22
Swamps, 27
Sweet Hall Marsh, Virginia, 34 (ill.), 35 (map), 39
Swiss school of hill shading, 66
Terraces, underwater, 15, 94 (ill.)
Texas-Oklahoma boundary, 51 (ill.)
Thomas, H. H., 101
Thoroughfares, 34 (ill.), 35 (map), 39;
Eltham Marsh, 36 (ill.)
Tidal Basin, Washington, D. C., 16 (ill.)
Tidal deltas, 82 (ill.), 83 (ill.);
Barnegat Inlet, 84 (ill.), 85
Tidal inlet, Beach Haven, N. J., 85 (ill.)
Tidal marshes, stream development, 28 (ill.)
Tied island, 77 (ill.);
development--Napatree Point, Rhode Island, 92 (ill.)
Tombolos, 92 (ill.)
Topographic mapping, 72
Treasury Building, Washington, D. C., 16 (ill.)
Trees, 13 (ill.)
Tucker Beach, New Jersey, spit, 91 (ill.)
Underwater topography, 45;
best conditions for photographing, 47;
channel in Quantico Bay, 95 (ill.);
channels (natural) at Miami, Fla., 96 (ill.), 102;
channels, shoals, terraces--Roberts Creek, Virginia, 94 (ill.);
Chesapeake Bay, 90 (ill.)
United States Army Air Service, viii, xi, xii
United States Coast and Geodetic Survey, 74;
coast line charting, 87, 88;
Florida coast experiment, 93
United States Geological Survey, co-operation, xii
United States Land Office, 56
United States Military Academy, 8 (ill.)
United States Naval Academy, 7, 9 (ill.)
United States Naval Observatory, 13 (ill.)
United States Navy Air Service, viii, xi, xii
Vertical photographs, 1;
scale, viii, 74;
horizontal control, 74
Viewpoint, 1
Village, prototype, 54 (ill.)
Virginia, Eastern Shore mud-flat area, stream system,
41, 42 (ill.), 43 (ill.);
tidewater portion, 38
Visibility under water, 102
Volcanic craters. _See_ Craters
Volmat, J., 99, 101
War and Navy offices, new, Washington, D. C., 16 (ill.)
Wards Island, 15 (ill.)
Warwick Creek and Mulberry Island, Virginia, 24 (ill.), 25 (map)
Washington, D. C., Capitol, frontispiece, 7;
Library of Congress, 7;
mapping, 79;
part showing White House, Treasury, and many familiar features, 16 (ill.);
topographic map, part, opp. 22;
United States Naval Observatory, 13 (ill.)
Washington Column, California, 60 (ill.)
Washington Monument, 16 (ill.)
Wash-overs, 81 (ill.), 86 (ill.)
Watch Hill, R. I., 92
Water, Visibility under, 102
West Point, N. Y., United States Military Academy at, 2, 8 (ill.)
West Point, Va., 36 (ill.), 38;
marshes, 29, 30 (ill.)
White House, Washington, D. C., 16 (ill.)
Wichita Falls, Tex., 51
Wildwood, N. J., 98
Wintun Glacier, 58 (ill.)
Wright, Orville, ix
Wright, Wilbur, ix
York River, 38, 76, 83, 87;
shoreline, 77 (ill.)
Yosemite and Mt. Lyell topographic sheets, 61
Yosemite Valley, 60 (ill.), 61 (map)
FOOTNOTES:
[1] Cf. his The Use of the Panoramic Camera in Topographic Surveying,
With Notes on the Application of Photogrammetry to Aerial Surveys, _U.
S. Geol. Surrey Bull. 657_, Washington, D. C., 1917.
[2] H. E. Ives: Airplane Photography, Philadelphia, 1920, pp. 328-350.
[3] The Pamunkey gets its name from a tribe of Indians famous in the
early days of Virginian history but now reduced to a few families
living on a reservation situated on the banks of the river near
Lester Manor. Mattaponi is a combination name. The Mat and the Ta
unite to form Matta Creek. The Matta and the Po unite, and Ny Creek
is a tributary to the Po. The waters of these streams unite to form
the river, and the names Mat, Ta, Po, and Ny unite to form its
name--Mattaponi.
[4] A. H. Brooks, personal communication.
[5] Eric Mjöberg: A Proposed Aërial Expedition for the Exploration of
the Unknown Interior of New Guinea, _Geogr. Rev._, Vol. 3, 1917, pp.
89-106.
[6] The Use of Aerial Photographs in Topographic Mapping: A Report of
the Committee on Photographic Surveying of the Board of Surveys and
Maps of the Federal Government, 1920, _Air Service Information Circular
(Aviation) No. 184_, War Department, Washington, D. C., 1921.
[7] What can be done, however, by photographing obliquely from a
high altitude, thereby increasing the area in the field of vision,
is illustrated by Figure 54, which encompasses Lake Erie from one
shore to the other and, in its representation of the main features
of the region, is akin to maps on a relatively small scale, such as
1:1,000,000.
[8] J. W. Bagley: The Use of the Panoramic Camera in Topographic
Surveying, With Notes on the Application of Photogrammetry to Aerial
Surveys, _U. S. Geol. Survey Bull. 657_, p. 84. “The scale of the
photograph is given by the relation _f_/H, _f_ being the focal length
of the lens and H the height of the camera above ground.” (_Ibid._)
[9] E. Lester Jones: The Aeroplane in Surveying and Mapping, _Flying_,
June, 1919, pp. 438-441, 472, and 476.
[10] H. E. Ives: Airplane Photography, 1920, pp. 407-408.
[11] E. Lester Jones: Surveying From the Air, _Science_, Vol. 52, 1920
(Oct. 17), pp. 574-575, and _Engineering News-Record_, Dec. 16, 1920,
pp. 1184-1186.
[12] E. Lester Jones, _op. cit._ (_Science_), p. 575.
[13] J. Volmat: Application de la photographie aérienne aux levés
hydrographiques, _Comptes Rendus de l’Acad. des Sci. [de Paris]_,
Vol. 169, 1919, Oct. 27, pp. 717-718; _idem_: Rapport sur la mission
photohydrographique de Brest (1919), _Annales Hydrogr._ (publ. by
Service Hydrographique de la Marine, Paris), 3rd Series, 1919-20, pp.
191-220, with seven air photographs and corresponding sections from
French coast charts.
[14] H. Hamshaw Thomas: Geographical Reconnaissance by Aeroplane
Photography, With Special Reference to the Work Done on the Palestine
Front, _Geogr. Journ._, Vol. 55, 1920, pp. 349-376; reference on p. 369.