nents.
scale
lax" T
1),and
y: 1:95
'esults
lificant
photos
alytical
Spatial
alytical
or and
'idging
plans
15mm
As for
graphs
t failed
mm),
sed for
survey
omer's
lay be
acy of
evision
e map
ore it is
with a
ined it
ans at
/ three
sion on
; to be
of air-
eferred
board
, and
ired for
for the
for a
st fully
ned 15
or") of
, errors
S Were
>curacy
on the
values:
ne map
)5 mm,
of the
reach
to the
ometric
>ript of
aneous
graphicali presentation on screen, and then -on
plotter. For accuracy estimation horizontal and
vertical positions of the identical points in the map
manuscript revised on the basis of survey data, and
those in the map manuscript compiled from
tacheometer survey of 1:500 scale, 1993, were
compared. ( Table 3).
Table 3
Scale | Numbers of points having Disc-
map |discrepances rep.
manus 10.3 o4 los [os [t0 |16]max
skript
in plan
1:500 |11 [2 1 1 1 1.6mm
1:2000 | 11 3 1 2 [1.3mm
in height
1:2000] 31 © [50502 To 1. J [0.9mm
XY errors were 0,4 and 0,5 mm for the plans of
scales 1:500 and 1:2 000 respectively, and the error
in relief was 0,3 m. The latter result means that it is
possible to detect and make corrections in the relief
having a contour interval equal to 1 m or mo- re.
Blue, black and double-side copies were used for
the revision procedure. Air-photo interpretation
should be carried out simultaneously with
compilations of the manuscript of changes, the
manuscript of left con tours, or together with
corrections of the revised map manuscript. New and
corrected contours were applied to the blue copy,
and the former ones were removed from the black
copy. Drawing of the revised map manuscript was
performed in accordance with the symbols adopted.
New elements were agreed with those that were left.
By means of simultaneous copying of "the map
manuscript of changes" and "the map manuscript of
the left contours" made on a transparent base, a
revised composite drawing was received. It was
checked basing both on 1:500 tacheometric survey
data, and on field interpretation of air-photos of
1:2000 and 1:10000 scales. Comparison results
have shown that interpretation of the air-photos
obtained from MDP survey is quite the same in its
fullness as that while we employ other carriers.
Percentage of in-door and on-board air visual
interpretations amounted to 80-85% in comparison
with the field interpretation. To meet customer's
demands the map manuscript is copied in a required
humber, or "the manuscript of changes" is prepared,
and then in-printed into a certan part of the map
issue, or multi-colour reproduction is provided.
3.CONCLUSION.
Instructing technical document has been
compiled on the basis of the MDP air survey
results. It included: a description of MDP design,
objectives and a branch of MDP applications, main
325
specifications, technical requirements to air survey
equipment and to an air vehicle employed as a tool
for expeditious map revisions: the consecutive order
of work stages, and some peculiarities of
preparatory work and air surveying process itself:
instructions and procedures of reconnaissance
flights and landings for obtaining data about terrain
changes in the field; description of procedures for
expeditious revision of topographic plans and maps
at scales ranged from 1:500 to 1:10 000 with using
MDP. There are some recommendations of the
Instructing technical document we are presenting
here. They are as follows: The first technological
variant i.e. when a new aerial survey takes place, is
suitable in cases where significant terrain changes
are revealed, and the map is up-to-date by less than
80%. Map revision on the basis of MDP air visual
observations and field measurements during MDP
landings (when there is not any new air surveys) is
needed when changes of the terrain elements are
less than 20% ( the second variant). Before
designing the project it is necessary to study
customer's requirements with respect to an accuracy
of map elements being revised, final view of a
cartographic product, work dates, the available
information on the area to be surveyed. If a user is
the Federal Service of Geodesy and Cartography all
the obiects of the |-category of importance are to be
corrected. As far as topographic objects of the 2-nd
and 3-d categories of importance are concerned
their changes can be partially interpreted according
to a users order. The MDP performance
requirements are as follows : maximum comfort
should be provided for an operators and
topographer's jobs during the flight; control and
operation of the air survey equipment should not
effect on the pilot's body position while air surveying;
a good view for a topographer should be provided,
as well as steady fixing of a tape recorder and a
camera. It is recommended to use AFA-TE as a
mapping aircamera (as no lighter camera is
available yet) with an image size of 18x18 cm, focal
lengths of 70, 100, 140 or 200 mm, relative lens
aperture not less than 1/17, and a central-type
shutter with exposures of 1/80 -1/240 c or 1/40 -
1/120 c (depending on the illumination of the terrain
area to be surveyed). AFA turns should be within
limits of + 20° . Recommended scales of taking
photographs with respect to AFA focal lengths are
presented iin Table 4.
Air survey should be completed at least 2 months
before the revision work starts. Optimum speed of
MDP flight for air surveys of 1:12 000 and 10 000
scales is 70 km/h, and 60 km/h - for those of 1:6
000, 1:4500, 1:3000 scales. The data obtained
during the flight is compiled in the form of booklets
(with a 20x20 cm sheet size). Before starting MDP
flights the terrain areas planned to be surveyed
should bestudied and zones requiring special
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B4. Vienna 1996
