ENC Analyzer HVC Module
The challenge for ENC producers today is to ensure consistent encoding of features that span multiple ENCs. Features that are common to adjacent ENCs, and overlapping ENCs of different scale bands, are often encoded from different data sources, potentially leading to inconsistencies in the encoding of a feature’s spatial geometry and attributes.
The ENC Analyzer HVC module has been developed to assist ENC producers achieve a consistent presentation of their ENC data across cell boundaries and scale bands. It comes as optional module for ENC Analyzer.
Horizontal consistency refers to the consistent representation of features that span cell boundaries.
Vertical consistency refers to the consistent representation of features that appear in overlapping cells of differing usage / scale bands.
The ENC Analyzer HVC module performs horizontal and vertical consistency validation based upon the IHO S-57 Use of the Object Catalogue, chapter 2.1.8 Seamless ENC Coverage.
Horizontal consistency checks (applied to neighbouring cells of the same usage):
- Cells should not overlap by more than 0.125mm at compilation scale.
- There should be continuity of linear features between adjacent cells.
- There should be consistent encoding of attributes for adjacent features.
- There should be continuity of area features between adjacent cells.
- There should be no significant gap along the boundaries of bordering cells. Gaps larger than 0.25mm and less than 20mm at compilation scale are reported.
Vertical consistency checks (applied to overlapping cells of different usage):
- Check the positional consistency of overlapping or same real world features. Features more than a pre-determined distance apart, as determined by the Settings dialog, are reported.
- There should be consistent encoding of attributes for overlapping features.
- Navigable water of a small scale cell should not overlap non-navigable areas of a large scale cell.
- Navigable water of a small scale cell should be shallower or equal in depth to overlapping areas of navigable waters of a large scale cell.
- Check that same logical spot soundings are encoded at the same position.
- Soundings at the same (or near same) position, should have the same depth values and attributes defined.
- Small scale cells should not have areas of no coverage (M_COVR with CATCOV=2) where there is coverage available in a larger scale cell.
- Overlapping areas of a small scale cell should not have a higher CATZOC rating than that of a large scale cell.
- The coordinate multiplication factor COMF should be the same for all cells (also applies for overlapping cells)