Category Zone of Confidence (CATZOC) is the value used to highlight the accuracy of data presented on charts. Learn Marine’s Blog explains CATZOC in depth. Here’s an excerpt from that.
CATZOC in IHO S-4 standardBefore the ECDIS era, mariners used to assess paper chart accuracy via Source diagrams.
However, this was changed with the wider introduction of ENCs in the industry and the consequent introduction of CATZOC, which is described in the IHO S-4 standard.
The...