THE INTERNATIONAL HYDROGRAPHIC REVIEW

Finally, a detailed description of the challenges faced by the Chilean Navy Hydrographic and Oceanographic Service to update the chart of the Kirke Channel, located in the very southern extreme of Chile. [...] We wish everyone - the Editor, authors and readers of the International Hydro- graphic Review - to participate in the next 100 years of the International Hydro- graphic Organization with undiminished interest and in the spirit of international cooperation that has distinguished the centennial activity of IHO and its Review. [...] Presently, the HHM is implemented in ESRI ArcGIS with a 500 m resolution output and relies on the difference between the present and desired survey scores (or the hydrographic gap) to assess the quality of survey data. [...] 36 INTERNATIONAL HYDROGRAPHIC REVIEW MAY 2021 The HUG model, , is defined as (4) a measure of the difference (reported in meters) between the estimated present uncertainty, σpresent, and the maximum allowable uncertainty, σmax, each essentially taking the place of the PSS and DSS terms respectively, in the HHM. [...] Specifically, data were broken into three layers according to initial coverage of the study area and acquisition year (lower, middle, and upper) where the lowest layer includes any dataset that covers a portion of the study for the first time, the upper layer includes the most modern datasets, and the middle includes any data in between.