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Coordinate System page

This is the Next >> page accessed in WizGen, Basic project mode from the Title page or by selecting the Goto... button for Specify the coordinate system containing the input data from the Contents page.

It allows the user to specify the layout of the input data, define the number of Columns, Rows and Layers in the model and optionally change the units of measurement in the project from the Metric default setting.



TransGen uses the Eclipse standard ordering by default, as shown above. The ordering of data in the Eclipse standard and RMS output is always in row order.  In the Eclipse standard,  the origin of the model (Row 1, Column 1) is at the top left of the model.  Rows increase downwards, and the XY coordinates which define the position of the COORD lines are given relative to the model origin, with Y increasing downwards.

However, in other models the position of the origin and the direction in which rows and columns increase may differ.  (RMS for example, provides many options to output the data in different ways.)  Also, the co-ordinates that defined the positions of the COORD lines may be given as a local coordinate system relative to the model origin (as per Eclipse), or relative to a geographic origin with Y increasing upwards (the RMS default). The appropriate system must be selected; if  incorrect, the model will either be mirrored or the cells will be inactivated as they have a negative volume.

A diagram in map view, showing the nature of the Coordinate system is shown for each of the options.

  • The position of the origin is shown by a blue diamond

  • Rows are shown by bold red arrows, row numbers increasing with the length of the arrow

  • Columns are shown thinner arrows, column numbers increasing with the length of the arrow

  • The directions in which the X and Y coordinates increase are shown by black lines.  These coordinates are used to define the position of the COORD lines.


    • HINT:- System 3 RMS with real world coordinates (with Y increasing upwards) is a common form of RMS output.

    Defining the Coordinate System

    1. Either retain the System 1 Eclipse standard (default) or select the relevant coordinate layout for the input data. This setting defines the parameters for the TGAXES keyword in the TGDATA run file.

    2. Input the number of Columns, Rows and Layers in the current Grid-block model for the current project - no defaults are supplied for these values in a new project - values MUST be entered by the user. These settings will define the parameters for the DIMENS or SPECGRID keyword in the TGDATA runfile.

    NOTE:- If you click on either the <<Back or Next>> button to leave this page before inputting values for the Cols, Rows and Lyrs, the following Error Pop-up will be displayed.



    3. Optionally change the default Units setting from METRIC (i.e. in metres) to either FIELD (i.e. in feet) or LAB (i.e. in centimetres). This sets the units of measurement assumed in the project and sets the METRIC, FIELD or LAB keyword in the TGDATA run file.



    To continue the workflow, click on Next >> to view/edit the Included Data page.

    Alternatively, click on the << Back button to return to the Title page to view/edit the title for the current project and/or whether the data is treated as a Basic Project or a Flexible Project in the current runfile.

    Or click on the Contents button to access the Contents page to view/edit any of the current TGDATA file settings, inspect the project's TGDATA file and/or inspect the log generated by last ViewGen calculation.

    Click on Save to save any modifications made to the current TGDATA runfile.
    Click on Quit to exit from WizGen with or without saving the any changes to the TGDATA runfile.


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