Tidal harmonic analysis

TASK - Windows Edition 

A complete tidal analysis and prediction suite of software


What is TASK?

TASK (Tidal Analysis Software Kit) is a complete software solution for the harmonic analysis of data from tide gauges right through to the prediction of tides into the future and the production of fully formatted tide tables.

The original version of TASK was developed about 15 years ago and was based on the harmonic analysis techniques developed at the National Oceanography Centre (then the Proudman Oceanographic Laboratory) and used throughout the world.  However, TASK-2000 was based on an old command line interface (DOS for those that remember such things) and was not the easiest of programs to use (you had to precisely modify input configuration files in a text editor) and had no internal quality control. There was also no internal quality control which meant it was up to the user to spot any potential problems with the data that could lead to errors in output with no assistance from the software.

TASK – Windows Edition is a completely new version of the software.  There is little in common between TASK – Windows Edition, and TASK-2000 other than a very accurate mathematical harmonic analysis engine and the name.

In September 2015, NOC launched TASK - Windows Edition ver. 2.0 with numerous enhancements including a completely new plotting module (which replaces the old Microsoft Excel based template). This makes visual inspection and quality control of the data far easier.

The Philosophy behind TASK – Windows Edition

  • Produce a harmonic analysis package that is easy to use for the experienced tidal analyst and the beginner alike.
  • Create software that is robust and configurable yet quick to get the results you need.
  • Build in some intelligence so it can assess its own results to see if they look sensible.
  • Create a complete tide gauge to tide table solution.
  • Provide a set of tools to be able to deal with problematic data.
  • Create a documented workflow which can be followed to get consistent results.
  • Create a professional product suitable for both commercial use and academic research.
  • Uses only plain text files giving the user complete flexibility to choose their own supplementary tools and integrate the software into existing systems.

The Approach

TASK is a suite of individual programs which, although they can be used independently, are designed in such a way that they work together in an integrated manner.  The main components are:

  • TASK – Windows Edition   Use for launching the separate modules as required
  • TASK – Toolkit                      For processing, resampling and QA of data
  • TASK – DMT                         A separate data manipulation module
  • TASK – Analyse                   The main harmonic analysis module
  • TASK – Graph                      A simple Excel template for looking at data and quality control
  • TASK - Plot                            A dedicated plotting tool to inspect and flag data easily
  • POLTIPS•3                            The Prediction Component with full tide table production

All programs are written to run under Microsoft Windows (XP, Vista, 7, 8, 10).  Apple users will need to dual boot to Windows, use a Virtual Machine (e.g. VMWare Fusion) or Windows Emulation (e.g. CrossOver).

The Basic Workflow

  • Get your data into a comma separated format (NOC-CSV, UHSLC or TASK format).  A basic level of knowledge in programs like Microsoft Excel makes this very easy.
  • Run the data through TASK-Toolkit which will carry out QA, resample the data and convert to the TASK file format.
  • View the TASK format file in the TASK-Plot module for an initial inspection to identify potential problems in the data.
  • Use TASK-Analyse to carry out a harmonic analysis of the data.  If you are happy with the results you can select to have the POLTIPS prediction software automatically update itself so that you are ready to produce fully formatted tide tables.
  • Alternatively check the data in the TASK-Plot module – it will now show the gauge data, the prediction made from the computed harmonics and the residual.  You can flag any data that looks bad if you wish, save the file and reanalyse.
  • Use POLTIPS to produce your finished tide table if required, or compute interval data, turning points, graphs etc., for any date and time period required (subject to the license purchased).

A Few of the Features

  • Reads in simple CSV file formats (including data directly downloaded from University of Hawaii Sea Level Centre)
  • Native file format is plain text with tools for simple manipulation and checking. This format has a data quality flag and supports 5 data channels (three are usually used for observation, prediction and residual)
  • Data quality control is automatically carried out (e.g. gap detection, clock jumps).  Potential problems are highlighted with an advisory flag and the analyst can choose to include/exclude these in the analysis or manually inspect each one using TASK-Graph.
  • Intelligent quality control in the analysis engine - the software carries out hundreds of checks throughout the analysis process to see if the data looks sensible and the results it computes are reasonable.
  • Data resampling and format conversion.
  • Data manipulation can shift and scale data (Dnew = m.Dold + c  ;  m and c set by user).
  • Time shifting to correct for time zone issues, daylight saving etc.
  • Handles data in any time zone.
  • TASK-Plot for easy viual inspection of large amounts of data along with tools to flag data to be excluded from the analysis. 
  • TASK-Graph template works in Microsoft Excel (2007 onwards) – data is imported by the single click of a button. Graph can be zoomed and scrolled easily using the scroll bar and zoom buttons.
  • A selection of preset harmonic constant sets for different data lengths, but custom configurable for the more experienced analyst.
  • Automatic calculation of daily, monthly and annual means if required.
  • Sensible auto file naming and overwrite protection.
  • Drag and drop input files straight intoany of the modules.
  • Automatic blocking of data is done completely behind the scenes – no need to fill gaps.
  • Over 100 harmonics if required.
  • Quality control statistics are output as part of the analysis process.
  • POLTIPS•3 prediction software can produce complex tide table layout and graphs etc.  Complete integration means the TASK-Analyse module will automatically update the POLTIPS database and your new analysis appears instantly in the list of ports.
  • Comprehensive documentation.
  • Automatic double analysis for tidal currents (east-west and north-south going-currents both contained in a single .t2kc file.
  • E-mail support for commercial users and academic users.

Contact the Marine Data Products Team for more info and prices.

Screenshots from TASK - Windows Edition

Last updated: Sept 2015


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