Applying unit conversion and rounding rules

Unit conversion allows data values to be stored as different units without the loss of information when imported and/or edited in the geodatabase. Once unit conversion and rounding rules have been configured, the system needs to know how to use the rules. Different products can have different rules applied. A set defines a rule base for a product defined by a given product.xml file. For example, a charting product might require detailed rounding rules to produce sounding labels in a specific format, while for an ENC product, you might simply need to output values truncated to a certain number of decimal places.

To define how the unit conversion and rounding rules are applied for a given product definition (product.xml), the rules need to be associated for each HUNI, DUNI, and PUNI field (source field) and its associated converted unit fields (destination fields). When converting from each source unit to a destination unit, the system needs to know which rules to apply. For example, the source field DEPTH has four destination fields: DEPTH_M (meters), DEPTH_FT (feet), DEPTH_FM (fathoms; fathoms and fractions), and DEPTH_FF (fathoms and feet).

When converting from meters to feet, the system uses the METERS2FEET unit conversion rule.


By default, all products supported by the ESRI Nautical Solution will have N/A defined for all unit conversion fields. If your agency requires specific unit conversion or rounding rules, they will need to be set before importing or compiling S-57 data.

  1. Start ArcMap.
  2. On the main menu, click Customize > Production > Production Properties.

    The Production Properties dialog box appears.

  3. Click Nautical Properties.
  4. Click the cell next to Unit Conversion.
  5. Click the ellipsis (...) button.

    The Unit Conversion and Rounding Rule Configuration dialog box appears. Values for all supported nautical products are set to N/A by default, meaning no specific values are set. You can proceed with importing, editing, and exporting S-57 data with this preconfigured setting. However, if your agency has specific unit conversion values and rounding rules, you need to set them properly.

  6. If you have previously defined unit conversion and rounding rules, you can click Automatic Populate to set those values within the dialog box.

    To remove a set of unit conversion and rounding rules for a given product, choose the product from the Current Set drop-down list and click Delete.

  7. Click OK when you are finished configuring unit conversion and rounding rules.