Reading the nautical charts number elevation notes

Other things you should take notice of when looking at the nautical chart are:
The chart number. The chart numbers differentiate charts of the same area.
Elevations note, which describes the datum used to indicate the clearance of bridges and overhead cables and the elevation of constructions.
Notes and warnings In the title block you may find notes and warnings
concerning the nautical chart. By reading them carefully you will decide if they are applicable to your voyage.
Datum note This datum note may reed ” WGS-84 (World Geodetic System 1984)” , “WGS or “Positions obtained from satellite navigation systems referenced to the WGS-84 can be directly plotted on this chart.”.
It is crucially important that your GPS is set to use the datum of the chart that you are using!
Chart corrections and edition. In the bottom left corner of the chart you will find the chart corrections by year and number, which were applied on the chart. Corrections are published several times a year in the notices to mariners.
Chart Abbreviations and symbols. There is a book named Chart Abbreviations and symbols, where you may find an entire index of abbreviations, a key to all of the chart symbols, and an explanation of the IALA buoyage system. In addition you may find general features, topography, hydrography and aids to navigation.