Common use of Data Quality Control Clause in Contracts

Data Quality Control. ODV facilitates quality control of multi-parameter datasets by providing a range of automat- ic and visual checks for easy identification and flagging of outliers and suspicious data. There is support for automated range checks of any basic variable (use option Tools>Find Outliers (Range Check)) as well as automatic statistical outlier checks for any data window currently applying the VG gridding method (use option Extras>Find Outliers (Field Check) of the data window’s popup menu). In both cases, ODV generates lists of suspicious data points and allows user controlled (point by point) or automatic flagging of the identified data. In addition to automatic quality control procedures, ODV also provides a wide range of easy-to-use visual and interactive methods for the identification and editing of outliers. For instance, you can plot all data from a given region or along a given section using data win- dows of SCATTER or SECTION scope, easily revealing outliers and questionable data in the entire dataset. Flagging or editing the numerical values of the spurious data is as easy as clicking on such a data point in one of the data windows and invoking the Edit Data option of the variable that you want to modify. Note that all changes made to a data collection are logged in the collection logfile. The log record includes information about the sample that was changed, the date and time of the modification, the user who made the change and the computer on which the operation was performed. You can browse the collection logfile at any time using option Collection>Browse Log File. In the example below, outliers for salinity and oxygen can easily be spotted in the plots showing the data of an entire cruise. Clicking on such an outlier point selects it as current sample, which can then be edited and/or flagged. You can hide and exclude bad or ques- tionable data from the analysis by establishing data quality sample filters. 7 Importing XYZ Data‌ Irregularly spaced or gridded data for some quantity Z at given X and Y coordinates are commonly provided in files using three-columns for the X, Y and Z values, respectively. Ex- amples of such XYZ datasets are (1) maps of a given Z variable (X represents longitude, Y represents latitude), (2) vertical sections (X=along section coordinate, Y=depth) or (3) time- evolution plots (X=some geographical coordinate, Y=time or vice versa). You can load all these XYZ files into ODV and you can analyze and display the Z data using the full suite of ODV functions. Note that the procedures described below can also be ap- plied to data files with multiple Z variables, e.g., files with more than three columns. Here is how to proceed if the XYZ file represents a map: 1. Create a new collection (choose a destination directory and collection name) with just two variables Depth [m] and Z-variable (use a descriptive label and appropriate units for the Z-variable), 2. Import the XYZ file by choosing Import>ODV Spreadsheet and selecting the XYZ file (note that you have to choose file-type All Files, if the extension of the XYZ file is not 3. On the Spreadsheet File Properties dialog specify (1) the column separation charac- ter (the items from the header line should appear on separate lines in the Column Labels list), (2) the line number containing XYZ labels (keep 1, if no labels are provid- ed), and (3) the line number of the first data line, 4. On the Metadata Variable Association dialog associate the X-variable with Longitude [degrees_east] and the Y-variable with Latitude [degrees_north], 5. On the Import Options dialog associate the Z-variable (source) with the second col- lection variable (target). Then click on the first collection variable (target), click on Use Default and specify the default depth value (use 0, if in doubt). ODV will import the data from the XYZ file, and lets you operate on the data in the usual way. To create a page with a map of the Z-variable create a data window with SURFACE scope. Modify the data window’s properties as usual, if this is necessary.

Data Quality Control. ODV facilitates quality control of multi-parameter datasets by providing a range of automat- ic au- tomatic and visual checks for easy identification and flagging of outliers and suspicious data. There is support for automated range checks of any basic variable (use option Tools>Find Outliers (Range Check)) as well as automatic statistical outlier checks for any data window currently applying the VG gridding method (use option Extras>Find Outliers Outli- ers (Field Check) of the data window’s popup menu). In both cases, ODV generates lists of suspicious data points and allows user controlled (point by point) or automatic flagging flag- ging of the identified data. In addition to automatic quality control procedures, ODV also provides a wide range of easy-to-use visual and interactive methods for the identification and editing of outliers. For instance, you can plot all data from a given region or along a given section using data win- dows windows of SCATTER or SECTION scope, easily revealing outliers and questionable data in the entire dataset. Flagging or editing the numerical values of the spurious data is as easy as clicking on such a data point in one of the data windows and invoking the Edit Data option of the variable that you want to modify. Note that all changes made to a data collection are logged in the collection logfile. The log record includes information about the sample that was changed, the date and time of the modification, the user who made the change and the computer on which the operation was performed. You can browse the collection logfile at any time using option Collection>Browse Log File. In the example below, outliers for salinity and oxygen can easily be spotted in the plots showing the data of an entire cruise. Clicking on such an outlier point selects it as current cur- rent sample, which can then be edited and/or flagged. You can hide and exclude bad or ques- tionable questionable data from the analysis by establishing data quality sample filters. 7 Importing XYZ Data‌ Irregularly spaced or gridded data for some quantity Z at given X and Y coordinates are commonly provided in files using three-columns for the X, Y and Z values, respectively. Ex- amples Examples of such XYZ datasets are (1) maps of a given Z variable (X represents longitudelongi- tude, Y represents latitude), (2) vertical sections (X=along section coordinate, Y=depth) or (3) time- time-evolution plots (X=some geographical coordinate, Y=time or vice versa). You can load all these XYZ files into ODV and you can analyze and display the Z data using us- ing the full suite of ODV functions. Note that the procedures described below can also be ap- plied applied to data files with multiple Z variables, e.g., files with more than three columns. Here is how to proceed if the XYZ file represents a map: 1. Create a new collection (choose a destination directory and collection name) with just two variables Depth [m] and Z-variable (use a descriptive label and appropriate ap- propriate units for the Z-variable), 2. Import the XYZ file by choosing Import>ODV Spreadsheet and selecting the XYZ file (note that you have to choose file-type All Files, if the extension of the XYZ file is notnot .txt). 3. On the Spreadsheet File Properties dialog specify (1) the column separation charac- ter char- acter (the items from the header line should appear on separate lines in the Column Col- umn Labels list), (2) the line number containing XYZ labels (keep 1, if no labels are provid- edprovided), and (3) the line number of the first data line, 4. On the Metadata Variable Association dialog associate the X-variable with Longitude Longi- tude [degrees_east] and the Y-variable with Latitude [degrees_north], 5. On the Import Options dialog associate the Z-variable (source) with the second col- lection collection variable (target). Then click on the first collection variable (target), click on Use Default and specify the default depth value (use 0, if in doubt). ODV will import the data from the XYZ file, and lets you operate on the data in the usual way. To create a page with a map of the Z-variable create a data window with SURFACE scope. Modify the data window’s properties as usual, if this is necessary.