1Seven operations turn a survey requirement into a usable map
Reconnaissance, Planning &
preparation, Horizontal control, Vertical control, Topographic
survey, Hydrographic
survey, Map preparation
2Reconnaissance steps
Reference marks, Water-level station, Access & routes, Hazards & conditions, Existing information, Feasibility
3Find existing monuments and possible new control locations.
1 Reference marks
4Identify a stable, accessible and representative gauge site.
Water-level station
5Check launch points, traverse routes, navigation constraints,
and permits.
Access & route
6Note obstructions, traffic, currents, exposure,
communications, and security
Hazards & condition
7Review prior surveys, charts, base maps, imagery, and local
knowledge
Existing information
8Confirm that the intended method, vessel, schedule, and
coverage are realisti
Feasibility
96 Planning Questions
Purpose, Extent, Method, Resources, Schedule, Risk
10What will the client decide, and what accuracy or
standard applies?
PURPOSE
11Where are the limits, depth range, access points,
and priority areas?
EXTENT
12How will positions, depths, water levels, shoreline,
and features be measured?
METHOD
13 Which vessel, sensors, software, personnel,
permits, and support work are needed?
RESOURCES
14What tides, weather, traffic, daylight, and
mobilization constraints control timing
SCHEDULE
15What can cause unsafe work, data failure, delay, or
cost overrun—and what is the fallback?
RISK
16Answers: Where is the sounding?
HORIZONTAL CONTROL
17Answers: Relative to what level?
VERTICAL CONTROL
18Field acquisition combines the _____
visible shoreline and unseen
bottom
19Map the adjacent land-water
interface
TOPOGRAPHIC SURVEY
20Measure the bottom and submerged
features
HYDROGRAPHIC SURVEY
21Quality depends on both the
accuracy and density of observations
22Before and during the acquisition process
PLATFORM, POSITIONING, DEPTH SENSOR, ANCILLARY SENSORS, CHECKS, BACKUPS
23Seaworthy vessel or suitable craft; stable
mounting; safe working space
PLATFORM
24GNSS or other method configured to the
required reference system.
POSITIONING
25Sounding pole, lead line, single-beam,
multibeam, lidar, or suitable technique.
DEPTH SENSOR
26Water level, sound speed, motion,
heading, draft, and time synchronization
as required.
ANCILLARY SENSORS
27Offsets, calibration, comparison
measurements, crosslines, coverage, and
daily review.
CHECKS
28Spare power, storage, cables, field
records, alternate instruments, and
recovery plan
BACKUPS
29Data Processing
INGEST, CORRECT, CLEAN, VERIFY, BUILD, ARCHIVE
30Preserve raw data, logs, calibration records, and metadata.
INGEST
31Apply position, water level, draft, sound speed, motion,
timing, and datum corrections as applicable.
CORRECT
32Review outliers and artifacts without deleting valid shoals or
significant features
CLEAN
33Examine coverage, overlaps, crosslines, uncertainty, feature
detection, and consistency.
VERIFY
34Create soundings, surfaces, contours, charts, profiles,
volumes, and reports appropriate to purpose
BUILD
35Package source data, processed results, metadata, quality
evidence, and limitations.
ARCHIVE
36Daily review prevents small field problems from becoming
survey gaps
CHECK, TEST, ACQUIRE, REVIEW, DECIDE
37Hydrographic surveying workflow
PLAN, CONTROL, MEASURE, VERIFY, DELIVER