The NOAA Mean High Water (MHW) files (mhw.gtx) and the corresponding TSS files (tss.gtx) can be used to create GeoCue vertical datum grid files that support the Mean High Water Tidal datum in GeoCue. One MHW/TSS pair exists for each of the thirty eight NOAA defined coastal project areas. This note describes the GeoCue workflow for creating and inserting the necessary files into GeoCue so that the MHW tidal datum is available in the set of GeoCue vertical coordinate systems. By following through this process using the other NOAA provided files one may also make MLLW and the other tidal datums available:
DTL – Diurnal Tide Level: The arithmetic mean of mean higher high water and mean lower low water.
MHHW – Mean High High Water: The average of the higher high water height of each tidal day observed over the National Tidal Datum Epoch. For stations with shorter series, comparison of simultaneous observations with a control tide station is made in order to derive the equivalent datum of the National Tidal Datum Epoch.
MHW – Mean High Water: The average of all the high water heights observed over the National Tidal Datum Epoch. For stations with shorter series, comparison of simultaneous observations with a control tide station is made in order to derive the equivalent datum of the National Tidal Datum Epoch.
MLLW – Mean Low Low Water: The average of the lower low water height of each tidal day observed over the National Tidal Datum Epoch. For stations with shorter series, comparison of simultaneous observations with a control tide station is made in order to derive the equivalent datum of the National Tidal Datum Epoch.
MLW – Mean Low Water: The average of all the low water heights observed over the National Tidal Datum Epoch. For stations with shorter series, comparison of simultaneous observations with a control tide station is made in order to derive the equivalent datum of the National Tidal Datum Epoch.
MTL – Mean Tide Level: The arithmetic mean of mean high water and mean low water.
Read the full article: CueTip – Creating Tidal Datum Grid Files
