Data Format Export Options Explained
There are a lot of data formats which can be exported from Hydrosurvey software. Please see below for further explanations.
1. X, Y
X,Y is under local Geographic coordinate system, X represents for N, Y represents for E, it is under
Geographic coordinate system but not Cartesian mathematical coordinate system so not X represents for E,
not Y represents for N.
2. B, L
They are under the WGS84 Geographic coordinate system, B represents for Latitude, L represents for
Longitude.
3. Water Level Elevation
It is the water surface elevation under local Geographic coordinate system, so if you work in the environment
with flat water surface, it would be almost a fixed value.
4. Depth(High depth and low depth)
Basically there are two kinds of echo sounder for simple bathymetric survey, that is dual frequency echo
sounder(DFES) and single frequency echo sounder(SFES), the frequency of transducer for DFES is 20KHZ and
200KHZ.
200KHZ is high frequency for echo sounder to conduct the survey, so the exported data measured via the
200KHZ transducer will be add a high title like high depth, meanwhile, 20KHZ is a low frequency, so exported
data using 20KHZ transducer would be added low title like low depth.
As USV Aapche series equip with 200KHZ transducer, so we basically export the data with High title like high
depth, high seabed elevation etc.
5. Seabed elevation
It is the elevation of bottom water under local Geographic coordinate system.
6. Seabed height
It is the height under WGS84 Geographic coordinate system.
7. Mud Thickness
It is the value that depth measured with low frequency transducer minus depth measured with high frequency
transducer, so this data is mainly used for dual frequency echo sounder.
8. Speed
It is the speed of boat.
9. Flow Velocity
We can get the water flow with USV real time, it is mainly developed for Hydrological survey, in order to get an
accuracy data from ADCP, we need to make automatically change the speed of boat in real time based on the
water flow, we call it adaptive water flow technology.
10. Flow direction
Flow direction is the direction of water flow.
11. Line Distance
Line Distance is the distance between the current position of USV and 'Home' point.
12. Track Distance
Tack Distance is the total distance of trajectory of USV
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