HEINESEN, Signar P. (À Oyrareingjum 114, Oyrareingir, FO-415, FO)
| P A T E N T C L A I M S 1. Method of providing a validity check of data sets obtained from measurements in a measuring environment, said measuring environment incorporating a number of observation stations each comprising at least one measuring instrument and an instrument controlling device for the controlling of the at least one measuring instrument and where said measuring environment comprises a processing device for storing, manipulating and displaying a data set comprising a plurality of observations made by an observation station deployed at an observation site, c h a r a c t e r i z e d in that the processing device stores templates each defining a setup of the observation stations, and procedure protocols defining a preparation procedure for managing the observation stations with a specific setup when preparing a measurement, and stores journal protocols logging the actual preparation of a measurement, the processing device adds a flag to an observation of a data set received from an observation station when the value of an observation exceeds a predetermined value, and the processing device displays a first graphical interpretation of data points determined from observations of the data set, which graphical interpretation comprises an indication of the relation between flags added to the data set and the corresponding data points. 2. Method according to claim 1, wherein the processing device in a second graphical interpretation of the data set displays the observa- tions of the data set used to determine the data points comprised in said first graphical interpretation. 3. Method according to claim 2, wherein the processing device simultaneously displays said first graphical interpretation of data points defined by the data set of a measurement adjacent to said second graphical interpretation of observation data defining the data points comprised in said first graphical interpretation. 4. Method according to claim 1 to 3, wherein information of the flagged observations of a data set is used to determine possible interpolations of observations in the data set. 5. Method according to claim 4, wherein the flags added to a data set is utilized perform a diagnosis check of an observation station. 6. Method according to any previous claim, wherein the processing device stores in a file a data set of a measurement including the provided template of the observation station used for a particular observation, the corresponding procedure protocol and journal protocol, the criterions for adding flags to a data set, a log of manipulations and interpolations made on the data set. 7. Method according to any previous claim, wherein the proce- dure protocol defining a procedure for managing an observation station is listed as a sequence of steps to be conducted when preparing a measurement or during maintenance and operation of an observation station deployed for the measurement. 8. Method according to any previous claim, wherein the journal protocol logging the preparation of a measurement is listed as a sequence of steps that have been conducted during the preparation of a measurement or during maintenance and operation of an observation station deployed for the measurement. 9. Method according to claims 7 and 8, wherein an electronic re- source associated with the steps of the journal protocol or the procedure protocol. 10. Method according to claim 7 to 9, wherein the steps of the procedure protocol is displayed in a first listing and the steps of the journal protocol is displayed in a second listing adjacent to the first listing simultaneously. |
The present invention relates to a method of providing a validity check of data sets obtained from measurements in a measuring environment, said measuring environment incorporating a number of observation stations each comprising at least one measuring instrument and an instrument controlling device for the controlling of the at least one measuring instrument and where said measuring environment comprises a processing device for storing, manipulating and displaying a data set comprising a plurality of observations made by an observation station deployed at an observation site.
In the technical field of conducting met-ocean measurements of for instance sea waves and sea currents, the interpretation of data qual- ity of data sets of a measurement and how such data sets are interpreted differ from the person conducting a measurement and providing a data set, to the person actually using a data set resulting from a measurement. The process of conducting measurements in itself requires detailed planning and documentation in order to certify the process of a measurement. As the physical requirements and the use of measuring equipment from different equipment vendors typically differs, it is difficult and time consuming to provide the documentation and guarantee the data quality of a measurement in a way that is readily accepted and understood by persons using data sets resulting from such measure- ments. Hence many different persons with a different focus on the process of planning and using measurements are involved as important players in a measuring process. When a measurement has been made it is necessary to make a validity check of the data set resulting from the measurement, i.e. to determine if the ranges of the values contained in the data set are within a predefined range determined on basis of inherent properties of the parameters, which are observed during the measurement, and the values that are expected to be measured during a given measurement of different parameters.
The person actually using a data set from a measurement for planning or research purposes needs a certainty that the obtained data set is suitable for the intended purpose and that the data set possesses a certain level of quality. However, there exist no common approach or standard of assessing data quality and providing a validity check of data sets from such measurements, and therefore the validity check of data sets from measurements is an ambiguous requirement, which is fulfilled by letting an experienced person, using individually developed routines and with years of experience, detect and correct errors in a data set. In practice, data quality is therefore based on prior experience and a per- son's reputation, and the standard for a validity check of data sets from measurements may differ over time and from person to person. Hence local standards of interpreting data sets and algorithms or routines for providing a validity check of data set are difficult to compare, as they are often not documented in detail or documented in different ways. Another aspect is the issue of providing documentation of the algorithms or routines used for conducting a validity check of a data set and how it was applied to the data set, when the data is delivered to the person to actually use the data set. Hence it is desirable to provide a tool that provides for a well-documented and structured utilization of prior experience and knowledge of how a validity check of a data set may be documented.
As the data sets from measurements comprise an enormous amount of data to be handled manually in order to provide a validity check, computerized control of the operation of measurement equipment in a measurement environment as well as subsequent processing of data measured by the measurement equipment as such are well known in the art. However, the above-mentioned problems of handling huge amounts of data in a structured manner, and ensuring quality and documentation throughout a measurement until the final result is delivered to the end user are not solved in the prior art. A typical example in the prior art is disclosed in CN101231167, which discloses a method for correcting submarine topography measurements comprising the steps of transmitting a measurement to a computer through a data wire, processing the data and displaying different visualizations of the measured data on a display so that data errors may be adjusted in a final step of the method. In JP2007333564 a sea wave measurement system for measuring wave heights and wave lengths is disclosed, where a filter removes noise components of the measurements before the data is processed and used to characterize the measured waves and their threshold val- ues.
The object of the present invention is to take the use of information and control technology in a measurement environment a step further by providing a method to be implemented as an information and observation system that will significantly improve quality management and control in a measurement environment by providing to the user of the system an overview of the excessive amount of data measured by observation stations in order to facilitate a manual data quality control and manipulation of the measured data, while the process of conducting measurements is being documented.
A further object of the invention is to facilitate exchange of data sets and prior experience between users of such measuring environment.
This object of the invention, as will appear from the following description, is accomplished by an information and observation system, which in its general aspect is characterized in that the processing device stores templates each defining a setup of the observation stations, and procedure protocols defining a preparation procedure for managing the observation stations with a specific setup when preparing a measurement, and stores journal protocols logging the actual preparation of a measurement, the processing device adds a flag to an observation of a data set received from an observation station when the value of an observation in a data set exceeds a predetermined value, and the processing device displays a first graphical interpretation of data points determined from observations of the data set, which graphical interpretation comprises an indication of the relation between flags added to the data set and the corresponding data points.
The kinds of measurements relevant to the present invention are made over relatively long periods of time, i.e. from months to years, at remote or not easily accessible locations. Therefore, planning and maintenance of a measurement are of utmost importance as a delayed or defective measurement may be crucial to the use of the data contained in a measurement of the conditions prevailing at a particular position or area where an observation station is deployed.
Planning and documentation of the preparation of a measurement are achieved by storing a template defining the particular setup of observation stations used in a measuring environment. Such templates may be delivered by manufacturers of the observation stations or by manufacturers of an instrument used in an observation station. Hence the templates may remedy the manufacturers to document the properties of the delivered equipment and to facilitate the documentation of the setup used for a measurement.
In relation to an observation station there are certain particulars that must be taken into account as a part of the normal operation and maintenance of a measurement. Such particulars may be defined by the equipment manufacturers or may be specified as a part of the requirements to the planned measurement. Such a particular may be a description of how an observation station is to be transported to the observation site for deployment and other facts relating the physical handling of an observation station or equipment deployed therein. Another particular of importance is how and when maintenance is to be conducted when an observation station has been deployed at an observation site.
A procedure protocol ensures that all such actions in relation to an observation station are described and it makes it possible to base a measurement on prior experience of how the practicalities of a measurement may be done and to fulfil requirements set forth by equipments manufacturers in order to maintain the properties of the equipment. Moreover, the orderer of a measurement may define actions of a procedure protocol to be fulfilled. A journal protocol serves to document which actions of a procedure protocol that have been conducted, including the particulars of how, when and by whom an action was conducted. This makes it possible to document that a measurement has been conducted in accordance with both the requirements of the orderer, the equipment manufacturers or to document the circumstances under which a meas- urement was conducted or an observation station was deployed.
As measurements are conducted over relatively long periods of time a data set resulting from a measurement comprises a very large number of observations. Moreover, an observation station does not only measure and log one single factor but several factors relating to the measurement of interest and it may log status information about the equipment of the observation station. Based on the nature of a particular measurement, and the equipment utilized for conducting the measurement and prior experience, the person planning an observation may de- fine a criterion, e.g. a threshold value or a range of values that are to be expected in a data set of a measurement. Alternatively, a flag may be added to a data set when an observation or a number of observations do not comply with a predefined criterion defined for the specific observation. If an entry in a data set lies outside the defined range a pointer may be added to that particular observation in the data set to allow for further investigation. This significantly improves the users overview of a data set and provides an indication of which details of the data set should be investigated in further detail and it furthermore serves as a data quality check as it ensures that all data in a data set lies within a certain range, which, in practice, is impossible by manual inspection of a data set. Hence more time may be dedicated to investigate and evaluate data points that lie outside a defined range. The observation of a data point in the first graphical interpretation is based on observations made during a period of time or alternatively on a number of observations, i.e. for instance by taking an average over a number of observations or of a period of time.
By displaying the data set in a graphical interpretation with an indication of the data points to which a pointer or a flag has been added, such data points are readily identified in relation to the whole data set and the particular data points of interest are seen in relation to adjacent data points. An indication of a flag in relation to a data point may simply be indicated by an arrow, a circle, a square or even a bar, which is indicated next to or on a data point of the graphical interpretation of a measurement. The graphical interpretation of a measurement in combination with the display of pointers or flags to data points to which the user's attention should be drawn provides for an optimum utilization of a computer screen in order to provide the user with an overview of excessive amounts of data, where only a minor fraction needs to be investigated in detail. Hence the method ensures a higher level of data quality by pin pointing the data points or observations that require some kind of decision or further attention by the user, but it brings the use of computers in relation to information and observation systems in a measuring envir- onment a step further in that it provides the user with an overview of which parts of the data set should be investigated and manipulated manually in order to ensure the same level or standard of data quality of the whole data set.
Preferably, the method according to the invention is imple- mented as an information and observation system to form part of a measuring environment. When implementing the method according to the invention on one or more processing devices in a measuring environment, it has the advantage that it may document and facilitate the measuring process from the initial planning and the manufacturer's specification of the equipment up to the subsequent study of a data set resulting from a measurement. Such an implementation of the method according to the invention entails that the end user of a measurement, without looking at the actual raw data, but by studying the documentation of the measuring process from the conduct of the measurement to the subsequent processing and manipulation of the data set which has been delivered to the end user, may determine if a given data set of a measurement is suitable for a specific purpose and if the measurement was conducted as specified.
Preferably, the processing device in a second graphical interpre- tation of the data set displays the observations of the data set used to determine the data points comprised in said first graphical interpretation. As the measurements are conducted over long periods of time a data point in the first graphical interpretation is normally an average over a shorter period of time or a number of observations, e.g. over half an hour, an hour or a day. Hence the observations of a data set may be provided with a indication such as a pointer or a flag to indicate that a threshold value has been exceeded or that a specific criterion pertaining the measurement is fulfilled or not.
Such information provided in a data set may be used to determine an average for a period of time and to determine if a further pointer or flag should be indicated in relation to such an average, i.e. as an indication in the first graphical interpretation. When the second graphical interpretation comprises a graphical interpretation of the ob- servations that makes up a selected data point in the first graphical interpretation, it readily provides an overview of the information inherent to the observations of a data set. This is very useful in order to determine if a particular observation is erroneous and possible why such error occurred. Advantageously, the second graphical interpretation of the ac- tual observation displays one aspect of the observed parameters as a graph in the frequency domain and another aspect of the observed parameters as a graph in the time domain. Preferably, at least two different representations of such details in the data set are displayed simultaneously. Moreover, the raw data adjacent to the measurement of inter- est, i.e. the measured value and a time stamp, may be displayed adjacent to the first and second graphical interpretations of a measurement. This gives a quick overview of a large amount of data and provides for a manual check and determination of the data quality since only a fraction of a large data set must be studied in detail.
The display of observations in a second graphical interpretation provides for a further utilization of a computer screen in a manner that is specifically adapted to analysing measurements where observations have been collected over long periods of time and in particular when analysing measurements where there is a need of displaying and analys- ing the observed parameters in different ways or on different scales. Hence it is possible to immediately analyse spectral data and burst data from a observation at a specific time, which may provide the information needed to determine the quality of a particular data point of a data set and understand if an observation is valid. When a range check of the values of a data set is conducted a pointer may be added to a data point being an aggregate of a number of observations or it may be added to a particular observation so that flags may be indicated on the second graphical interpretation and not only on the first graphical interpretation.
In a further development the processing device simultaneously displays said first graphical interpretation of data points determined from observations adjacent to said second graphical interpretation of the observations of the data set. This makes it possible to the user of an in- formation and observation system using the method according to the invention to flip through different data points of certain interest while seeing the underlying observation. Advantageously, the first and second graphical interpretations of a measurement are presented in different windows on a screen. This has the advantage that the resolution and size of a graph may be adjusted to specific needs and the hardware at hand for displaying graphs. For instance, it is useful and significantly reduces the time needed for subsequent manual study and processing of measuring data, if it is possible to drag a window displaying the second graphical interpretation to another screen next to a first screen while keeping the first graphical interpretation on the first screen.
In a further embodiment, the information of the flagged observations of a data set is used to determine possible interpolations of observations in the data set. This make it possible to remove data not being valid due to, for instance, data being logged before the entire obser- vation has been configured and deployed or if an instrument is fault but data is still logged. The actual manipulation of data may be made automatically but is normally made manually where prior experience and know how are utilized to obtain a complete data set fulfilling the specification set forth by the orderer of a measurement. Since such data sets of a measurement typically are used for making calculations or simulations, it is of great importance that all data points and observations of a data set are void and being usable as an interpretation of the real world. Therefore, a function making it possible to provide an interpolation between two data points or manually adjusting the data by activating the functionality in a program is very useful.
In a further development of the invention, the flags added to a data set is utilized to perform a diagnosis check of an observation station. Thereby the evaluation of the measurements not only serves to de- termine the validity of a data set, but also makes it possible to use the data of a measurement for the purpose of service and maintenance.
In a preferred embodiment, the processing device stores in a file a data set of a measurement including the provided template of the observation station used for a particular observation, the corresponding procedure protocol and journal protocol, the criterions for adding flags to a data set, a log of manipulations and interpolations made on the data set.
When all data relating to a measurement is stored in a single file, information and observation systems implemented according to the invention may serve as collaboration tool during the whole process of conducting and using measurements. As the process is documented along the different steps of the process, the end user of a measurement may be in a situation where there is no need to study actual data, but where the documentation of a measurement provides sufficient informa- tion. Preferably, the process is documented by writing the relevant data to a file having a standardized XML format.
An equipment manufacturer may, for instance, provide a template of the standard setup of equipment that readily may be read by a information and observation system according to the invention or in- eluded in a file from such system. A template, a procedure protocol and a journal protocol, and definitions of valid ranges of parameters observed during measurements, may also be used to exchange information from one user to another collaboration on a project. This further makes it possible to produce a report of a measurement comprising very de- tailed information about the individual observations and the specific configuration of an observation station, but also short status reports indicating the operation status of an observation station.
In a further development of the invention, the procedure protocol defining a procedure for managing an observation station is listed as a sequence of steps to be conducted when preparing a measurement or during maintenance and operation of an observation station deployed for the measurement, and in an even further development the journal protocol logging the preparation of a measurement is listed as a sequence of steps that have been conducted during the preparation of a measurement or during maintenance and operation of an observation station deployed for the measurement.
The journal protocol or the procedure protocol may list the steps in chronological order by data or by prioritized order where urgent tasks are listed first. Alternatively, the steps may be listed by type such as transports tasks in relation to deployment of an observation station, service tasks during deployment or as tasks relating to data collection and data acquisition, which are relevant when an observation station is directly connected to an observation station and data collection/acquisition is conducted more or less automatically.
In a practical embodiment, an electronic resource may be associated with the steps of the journal protocol or the procedure protocol. Hence a link to a file storage on a local network or a link to the Internet may be associated with a step in a journal protocol or a procedure pro- tocol. Alternatively, a document may be attached to a step, which is a convenient way of documenting or disclosing steps conducted in such protocols. For instance, a receipt documenting the transportation of an observation station to an observation site or a report documenting that an instrument of an observation station has been calibrated could be at- tached to an item in the journal protocol in order to document the process in an efficient and practical manner.
In a practical embodiment, the steps of the procedure protocol are displayed in a first listing and the steps of the journal protocol are displayed in a second listing adjacent to the first listing, simultaneously. As disclosed in relation to the graphical interpretations of the data sets this embodiment also provides for a better overview of the data relating to the journal protocols and the procedure protocols. If, for instance, each displayed protocol is shown in different windows on a computer screen and they are adapted to be customized by the user, a more effi- cient system adapted to local needs and hardware is achieved.
The process of working with journal and procedure protocols is further improved when it is made possible to copy a part of a procedure protocol to the journal protocol.
In the following, the invention will be explained in greater detail with reference to the accompanying simplified schematic drawings, in which
Fig. 1 shows an observation and information system according to the invention,
Fig. 2 shows an observation station of an observation and information system,
Fig. 3 illustrates a procedure protocol displayed on a computer screen,
Fig. 4 illustrates a journal protocol displayed on a computer screen,
Fig. 5 illustrates a graphical interpretation of a data set of a measurement.
Fig. 1 illustrates a measuring environment 1 where a method according to the invention is implemented on a computer 2 as informa- tion and observation system. A number of observation stations 3 in this particular example being deployed for taking met-ocean measurements of wave heights. The communication between the observation stations and the computer 2 is achieved by a wireless communication link using, a satellite 4. Otherwise, an observation station 3 may be deployed at an observation site during a desired measuring period after which data is read out from the observation station 3 and loaded into the computer 2.
The observation and information system running on the computer 3 serves as a tool for planning a measurement as indicated by reference numeral 5 of Fig. 1. The observation and information system is used to document the planning process including details of which parameters are to be measured, what kind of equipment is to be used for building the observation station 3, but also the subsequent processing and manipulation of the observations made by an observation station 3 and gathered in a data set. An observation station 3 is an assembly of instruments controlled by an instrument controller. An observation station 3 typically comprises sensors, data loggers, a storage device and one or more communication device so that data sets and status information of the in- struments and the observation station may be communicated continuously to the computer 3. The instruments assembled in an observation station observe a number of parameters during the time period in which the observation station is deployed. Hence all aspects of planning measurements and the deployment of an observation station is made and documented in the computer 3.
In general, the setup of an observation station for a particular measurement may be defined by using a template, which at a first abstraction level may comprise the type of measurement, e.g. based on met-ocean measurements, the parameters to be observed and which in- strument type to be used for measuring such parameters, and finally a norm defining the expected range of the parameters to be measured. This level of the planning and the definition of a template is the most generic level that in general relates to the equipment manufacturers. Hence an equipment manufacturer may provide a template relating to an observation or a piece of equipment provided on an observation station.
On a second, more detailed level a template defining an observation station comprises the instrument model number, and the procedures relating to the particular instrument are defined, and specific details relating to a particular instrument are defined and disclosed.
In a next step of the planning process the details of a template relating to an observation station equipped and assembled for a specific purpose are described. These relate to the actual parameters to be measured and their definition, the applied units and the format of the data logged and stored in the observation station 3. Parameters may re- late to both a specific observation in time of a physical entity in the environment where the observation station has been deployed, but it may also relate to specific parameters of the observation station and its components such as battery level, communication signal strength and storage capacity. Hence a parameter is the logical entity of a measurement such as 10 m/s for mean wind speed and should therefore in general be considered as a value and so, when a parameter is defined, it is also decided how many digits it should be represented by and how a time series plot of the data set of a measurement may be configured.
The definition of a template is used to define a procedure protocol, which defines the tasks to be conducted in relation to the deployment of an observation station 3 and a corresponding journal protocol that will be described in more detail in relation to Fig. 3 and 4.
Fig. 3 and 4 show an example of how a procedure protocol and a journal protocol, respectively, are displayed according to the method of the invention when implanted on a computer in an information and observation system. At the left hand side a first field 100 is used to display details of the particular observation station next to a second field with panes 101 that are used to select if either the procedure protocol or the journal protocol should be viewed next to the first field 100. The first field 100 at the left hand side is used to show details of the particular deployment of an observation station such as the position of the observation site, the date of deployment, the owner of the observation station, etc. Different types of tasks as shown in the field 102 define a pro- cedure protocol or a journal protocol, respectively, depending on which of the panes 101 have been chosen. If a task type is chosen in the field 102 the steps relating to the chosen task are displayed in the lower field 103. An electronic file or a link to for instance a web page may be associated with a task type or a step of a task type as indicated by 105.
The use of procedure protocols 110 and journal protocols 120 in a method according to the invention makes sure that is it possible to document the quality of the process of planning and conducting measurements, i.e. it may be used to obtain, for instance, a ISO 9000 certification of the measuring process, where the graphical interpretation of a data set of a measurement on the other hand relates to the quality of the data set that has been collected during a measurement, i.e. for instance if the physical value of a parameter in a data set makes sense as a representation for what has been measured.
Instead of using the panes 101 to choose between a display of the procedure protocol 110 or a journal protocol 120, one of the two protocols may be displayed in a separated window next to a window showing the other. The procedure protocol 110 is used to plan a measurement using a specific observation station at a specific observation site and the journal protocol 120 is used to document how the measuring process was conducted. Additionally, other panes may be used for displaying the parameters to be measured or the equipment installed on an observation station.
The type of instruments used in an observation station depends on which parameters are to be measured. The type of an instrument may, for instance, be a wind anemometer or an instrument detecting wave height and/or wave direction of sea waves, whereas an instrument model is a specific model from a given manufacturer.
Fig. 2 shows an example of an observation station 10 deployed as a buoy 11 for conducting met-ocean measurements of wave heights and wave directions. The buoy was deployed 61 18 " N, 6 17 " W south of the Faroe Islands at a depth of 240 m. The observation station is equipped with a Directional Waverider of the type s/n 30175-5S from the manufacturer Datawell for measuring the direction and height of waves and includes a HF-transmission system operating at 29.705 MHz, a Warec receiver of the type s/n 31217 and a Datawell computer system with a data logging programme. Initially the data logger had a memory of 10 Mb but was updated to 40 Mb in order to provide sufficient storage capacity. The observation station 10 communicates via a satellite link with a computer 2 positioned on land in order to transmit data sets comprising a plurality of observations made by the instruments of an observation station to the computer 2 with an information and observation system. For the purpose of redundancy a second communication link such as an Argos satellite system, for collecting data on another central server, may be used to ensure a continuous communication with the observation station.
As shown in Fig. 2 the observation station 10 comprises a buoy 11 comprising the above-mentioned equipment and the buoy 11 is deployed by means of two rubber cords 14 of each 15 meters, which are used at the specification of the manufacturer Datawell. By means of a float 12 connected to a foundation 13 resting at the seabed, the rubber cord 14 is moored to the observation site. The foundation 13 is connected to the float 12 by a first chain 16 of approximately 10 meters, which is connected to a 22 mm cod line 17, which at the other end is connected to a second chain 17 connected to the float 12, which is positioned at a depth of approximately 40 meters. The foundation 13 is anchored to the seabed by anchors 15. An additional float 19 has been used during some periods of the deployment of the observation. It served to collect the mooring without straining the rubber cords. The above description of this particular observation station illustrates some of the requirements for planning and documentation of measurements and which are fulfilled by the method according to the invention.
Typically, the observations made by an observation station are stored in different file formats defined by the manufacturers of the equipment installed, but also a raw data format may be used to store observations. An example of parameters stored by an observation station for a single observation is shown in Table 1, which illustrates some examples of parameters observed and stored by an observation station or which parameters may be derived from an observation.
Table 1
Parameter value Parameter tvoe Unit
<86> significant wave height [cm]
<4,210526> mean period time (Tz) [sec]
<,4156937> maximum spectral density [m 2 /Hz]
<24,95> reference (dummy) temperature [C]
<8,45> sea surface temperature [C]
<6,125> battery condition (0-7) [0 - 7] < l,005> vertical accelerometer offset [m/sec 2 ]
<,005> X-accelerometer offset [m/sec 2 ]
<-,4325> Y- accelerometer offset [m/sec 2 ]
<239,0625> compass heading [deg] <73,21289> magnetic field inclination [deg]
< l,130608E-03> normalized spectral density S(f)/S(m) [1]
<60,46875> mean direction [deg]
<72,06731 > directional spread [deg]
< 1,959184> skewness [1]
<2,222419> kurtosis [1]
< 100> data coverage [%]
< 156> highest wave Hmax [cm]
<7,7> period of highest wave Tmax [sec]
< 105> l/10 th mean H 1/10 [cm]
<6,7> l/10 th wave height mean period Ti / i 0 [sec]
<83> l/3 rd mean H 1/3 [cm]
<5,9> l/3 rd wave height mean period J 1/3 [sec]
<53> mean wave height Havg [cm]
<4,4> mean wave period Tavg (=Tz) [sec]
<0,71 > spectral width EPSl [1]
The first column represents the observed value of a parameter or the value of parameter derived from other parameters. The second column in the middle indicates the type of parameter relating to an observation and the column at the right hand side indicates the unit used for each of the parameter types. The observations of the measurements conducted by the observation station 10 is received and stored at the computer 2 for further analysis and validity check of the received data sets. As seen from the example in Table 1 the observations may be represented in both the time and frequency domain and additional parameters may be derived from the raw data.
In a measurement of waves as the one disclosed above an observation is typically made every half second for a period for about 20 minutes. Such series of observations is normally considered as a burst, which is used to determine an average for the measured parameters. When conducting a measurement of for instance wind speed an observation of a period of about 2 seconds may be made every 10 minutes in case of what is considered as a simple measurement. However, when using an acoustic anemometer several observations per second may be made. Hence even a relatively simple measurement with a relatively low number of observation per time unit will result in hundreds of thousands of observations when a measurement, as often is the case, is conducted over several years, and these observations are to be investigated in order to provide a validity check of the observed parameters.
In order to provide an overview of the received data, the data sets are displayed as a graph on a computer screen as shown in Fig. 5 showing a preferred embodiment of the invention. This is done after a data set of a measurement has been processed and provided with pointers as described above. On the left hand side is shown a first graphical interpretation 20 of the data set resulting from a measurement. This graphical representation consists of three graphs 21, 22, 33, where the first graph 21 for instance shows the variance of the wave height over time, the second graph 22 for instance shows the mean period of time and the third graph 23 for instance shows the maximum spectral density of the measured waves. The content of these graphs and the data to shown in the left hand side of the graph may be chosen manually by using the menu bar 30. The three graphs comprise data points, which are derived as an average of a period of time where several observations have been made.
The pointers added to the data set to specific data points in the data set to which the user's attention and focus should be drawn are indicated by squares 24 along an axis of the graph. An indication of a flag may vary in shape, size and colour and may be added only once in relation to the first graph 21 or in relation to the graphs 21, 22, 23 of the first graphical interpretation 20 as necessary. It is also possible to provide more than one indication in relation to a data point. In order to check the quality of a data set of a measurement and thereby ensure that they are suitable for the intended purpose and that a measurement has been conducted as planned, i.e. the equipment of the observation station has been functioning properly and measured parameter values are valid, the data points which are to be studied more thoroughly are provided with a flag to indicate that a further investigation is needed. An indication in a data set such as a pointer or a flag should be understood as graphical indication on a graph or as administration data used to handle and process specific parts of a data set before displaying the data set in one or more graphs.
As the data points of the graphs 21, 22, 23 are calculated as the average over a longer period of such as 20 minutes or an hour or alternatively over a number of, for instance, waves measured at the observation site, the individual observations used to determine the average for such periods inherently contain a lot information that is of interest to the skilled person analysing a measurement and ensuring the data quality of a data set. This is done in an efficient manner by displaying the observations used to determine a data point in a graph 21, 22, 23 of the first graphical interpretation 20 in a second graphical interpretation 40. Hence the observations in a first graph 41 and a second graph 42 of the second graphical interpretation 40 are the data that makes up a data point in a graph of the first graphical interpretation and corresponds, for instance, to a specific number of observations or observations made during a period of time. The first graph 41 is a representation of the observation in the frequency domain, whereas the second graph 42 for in- stance shows the measured wave height over a period of 20 minutes. Such different graphical interpretations of the observation making up a data point in the first graphical interpretation is used to analyse the validity of a data point or an observation that has been flagged. The content of the second graphical interpretation 40 may be adjusted using programme functionalities found in the menu bar 30 if another parameter of a data set should be shown in one of the graphs 41, 42 or if yet another graph displaying detailed information should be shown.
When a user for instance by a click selects a particular flag in the first graphical interpretation 20 by using an input device such as a mouse or a keyboard attached to the computer 30, the observations making up the data point of the chosen flag is presented in the second graphical interpretation 40. Hence the user may simply click on a flag to see the relevant observations needed to determine the reason a flag has been added or simply shift between the flags using a tab or arrow key of a keyboard. To provide the user with an overview of the screen and the displayed observations, an additional bar 50 may be added to the first graphical interpretation to indicate which among the flagged data points are shown in detail in the second graphical interpretation 40. The indica- tion flags in combination with the display of the second graphical interpretation 40 have the advantage that only a fraction of a data set of a measurement has to be studied manually in order to check the validity and ensure the quality of a data set.
Moreover, the flags may be combined with a diagnostic check of an observation station, which check normally is made by utilizing the flags added to a data set. Hence, the result of a diagnostic check, which may indicate that a battery level of an instrument is below a certain threshold value or that a communication procedure failed due to insufficient signal strength for the communication link, may be indicated on the first and/or second graphical interpretations 20, 40 of the data set. This may, for instance, be done by changing the colour of a square indicating a data point that should be investigated further or letting such indication flash or change size.
As the experienced person in the present field of technology may also have an interest in viewing the raw data as clean text, a further data field 45 may be added to the screen displaying a data set. This field serves in combination with the first and second graphical interpretations 20, 40 to provide an overview of the data set so that the needed information is ready at hand. Again, the data shown in the data field 45 may be adjusted to specific needs by using the menu bar 30. Alternatively, F-keys and short cuts may be used to access or obtain the required functionality in the system.
When a validity check of a data set has been made the computer stores in a file a data set of a measurement including the provided template of the observation station used for a particular observation, the corresponding procedure protocol and journal protocol, the criterions for adding flags to a data set, a log of manipulations and interpolations made on the data set. This has the advantage that if the method according to the invention is implemented at both equipment manufacturers, the measurement planner, the data provider analysing the data sets of measurements and the final user of a measurement, and if a common format such as XML is used to document the process, the method facilitates the exchange of data and information between players involved in a measuring environment.