Measurement Dataset

Specifications Measurement Dataset

Background

The Covadem project (cooperative navigable depth measurements – Coöperatieve vaardieptemetingen) was launched in April 2013. The project is aimed at sharing real-time navigable depth measurements, that skippers can use to navigate more efficiently in the future and make maximum use of the navigable area provided by the waterway.

This is done as follows: Inland waterway vessels are provided with a basic on-board computer to read the data from existing sensors. Sensors such as the echo-sounder, loading gauge, GPS and fuel gauges. This data is combined into a message and send to shore. Based on these measurements, the real-time measured keel clearance is converted into the real-time water depth of the route being navigated. These real-time navigable depth measurements are made available to skippers so that, in future, this data can be used for predicting the water depths of the route to be navigated. Skippers can use real-time, accurate waterdepth to navigate a more efficient route. More efficiently, because sailing on deeper water consumes less fuel.

Measurement DatasetThe dataset consists of the following files:

grid-only-rotterdam-waal.kml: ASCII based file for the area containing the depth measurements as kml formatted file format.

measurementset.csv: ASCII based file with all the depth measurement data of sailing ships.

databaseSet.xml: ASCII based file in xml format describing the area and the containing measurements for each area.

The measurement dataset (measurementset.csv) consists of real-time depth measurements; data from existing sensors, such as the echo-sounder, loading gauge, GPS and the fuel usage. The measurement data set contains valid data of sailing ships only. Sailing ships are those ships with an average GPS speed over ground of over 1 km/hour for at least 10 minutes.

Measurement DatasetWrite

Processing Unitupload

MEMO

The measurement dataset measurement data is collected between August 1st 00:00:00 and August 31st 23:59:59. Measurements are recorded with a time period of 1 minute.

Each measurement is uniquely identified with a measurement id.Each measurement has a time stamp at which the measurement was taken.Each measurement has a GPS location where the measurement was taken.Each measurement has a ship id identifying the ship, being the source for the measurement.

The Measurement Dataset is an ASCII based file. Each depth measurement is on a single line. The depth measurement parameters are comma separated. The first line in the file holds the header line to identify the each depth measurement parameter.

Measurement Dataset ParametersParameter Description Typeid Unique identification for this

measurementLongexample: 870428521

shipid Identification number for the ship IntegerExample: 35

date The date and time of this measurement Date; formatyyyy-MM-dd-HH:mm:ssexample: 2015-07-31-23:55:23

lat GPS latitude position in decimal degrees, coordinate system is WGS84

float; format FF.ffffffexample: 51.833398

lon GPS longitude position in decimal degrees, coordinate system in WGS84

float; format FF.ffffffexample: 6.184142

sog Speed Over Ground, the speed measured by the GPS in km/hour.

float; format FF.ffexample: 10.59 km/hour

heading Heading measured by the GPS in degrees, range between 0 – 360 degrees. North = 0;

float; format FFF.ffexample 189.45 degrees

hdop Horizontal dilution of precision for this GPS measurement. The idea of Geometric DOP is to state how errors in the measurement will affect the final state estimation. See meaning of dop values for details.

float; format FF.fexample: 2.0

vdop Vertical dilution of precision for this GPS measurement. The idea of Geometric DOP is to state how errors in the measurement will affect the final state estimation. See meaning of dop values for details.

float; format FF.fexample: 1.6

stw Speed Through Water, the speed of the ship relative to the water, in km/hour.

float; format FF.ffexample: 9.75 km/hour

ukc The underkeel clearance in meters. The underkeel clearance is the vertical distance between the bottom of the hull

float; format FF.ffexample: 12.56 meter

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MEMO

and the bottom of the river.waterdepth Waterdepth is the calculated waterdepth

for this position. It uses the ukc, the ship’s draft and the speed through water to calculate the waterdepth, in meters

Float; format FF.ffexample: 5.67 meter

cargo The weight of the cargo loaded on this ship, measured in tons.

float; format FFFFF.fexample: 2543.5 tons

draftaft The draft at the aft of the ship. The draft of the ship's hull is the vertical distance between the waterline and the bottom of the hull (keel), in meters 

float; format FF.ffexample: 1.56 meter

draftforward The draft at the bow of the ship. The draft of the ship's hull is the vertical distance between the waterline and the bottom of the hull (keel) in meters

float; format FF.ffexample: 1.68 meter

fuelflow The amount of fuel flow measured in liter/hour

Float; format FFF.ffexample: 123.56 liters/hour

Additional informationMeaning of DOP values

DOP Value

Rating Description

< 1 Ideal Highest possible confidence level to be used for applications demanding the highest possible precision at all times.

1-2 Excellent At this confidence level, positional measurements are considered accurate enough to meet all but the most sensitive applications.

2-5 Good Represents a level that marks the minimum appropriate for making business decisions. Positional measurements could be used to make reliable in-route navigation suggestions to the user.

5-10 Moderate Positional measurements could be used for calculations, but the fix quality could still be improved. A more open view of the sky is recommended.

10-20 Fair Represents a low confidence level. Positional measurements should be discarded or used only to indicate a very rough estimate of the current location.

>20 Poor At this level, measurements are inaccurate by as much as 300 meters with a 6 meter accurate device (50 DOP × 6 meters) and should be discarded.

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MEMO

The measurement dataset contains measurements from ships within the boundaries of the measurement area.

Figure 1 Measurement Dataset Area

Figure 2 Example of the Measurement Dataset

Figure 3 Example of the Measuerment Dataset ASCII file

Figure 4 Example of the xml formatted Measurement Dataset

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