About References Included in Data
If you choose to use references to Sections within your data, Horizons validates these references against the Network Sections that are already present for your Network as it validates the data import operation. Errors are raised for any Sections that are referenced in the data that are not found on the Network.
Chainage Adjustments
If there is any chainage data present in your import, it is scaled to fit the digitized lengths of the Network Sections that are used by Horizons. Horizons holds two lengths associated with each network section:
- Section Length – the section length (m) of the section geometry as used in mapping, i.e. the Network Section Digitized Length
- PMS Length – the length (m) set as the measured length for that section for the purposes of surveying, i.e. the Network Section PMS Length
You can see the lengths in Explorer in the Information pane for a Section.
Chainages present in the data are assumed to be Survey Chainages and hence are expected to fit in the range given by the PMS Length for that Section. If your data has chainages that fit a different survey length, you can specify this length via a column in your data and identify it to Horizons as the Section Length (see Configuring Data Import Fields).
Chainage Validation
Horizons validates the Section Lengths in your data against the Network Section Digitized Lengths. Or if no data Section Length is specified, the Network Section PMS Length is validated against the Network Section Digitized Lengths. The validation operation flags errors for items out of tolerance. You can set the tolerances in the Configure Data Import window. See Importing and Configuring a Data Import.
A data item fails validation if the item’s Data Section Length (or if not specified, the Network Section PMS Length) differs from the Network Section Digitized Length by more than the distance defined by the Section Length Tolerance AND also by more than the Section Length Tolerance percentage.
You can also specify a Max Chainage Adjustment (optional). Setting this causes an error for the item if the conversion to digitized chainage requires an adjustment by more than the given absolute distance.