Format

Each GESLA-3 text file contains 41 lines of header information, followed by the data itself. The data itself is comprised of five columns, separated by spaces. These are: 

1. Date;
2. Time;
3. The observed sea level (m);
4. The quality control flag; and
5. The flag indicating wehther the data should be used for analysis or not.

Each data value has been assigned two flags. The first flag (in column 4) indicates the quality control undertaken by the provider. For this we use the following flags: 

• 0 for no quality control;
• 1 for correct value;
• 2 for interpolated value;
• 3 for doubtful value;
• for isolated spike or wrong value; and
• 5 for missing value (set to -99.9999).

Where available, we matched each of the provider flags to our system. The second flag (in column 5) is a 1 or 0 indicating whether that value should be used for analysis, or not, respectively. All values whose quality control flag was 0, 1 or 2 were set to analysis flag 1 (use), and all values whose quality control flag was 3, 4 or 5, were set to analysis flag 0 (do not use).

The name of each file is made up of the (lower case) site name, site code, country code, and an abbreviation of the contributor name, separated by a hyphen (e.g., brest-822a-fra-uhslc).

A example of the 41 header lines from a GESLA-3 data file (brest-822a-france-uhslc) is shown below:

# FORMAT VERSION 5.0 Web: https://gesla.org Email: gesla.help@gmail.com

# SITE NAME Brest

# SITE CODE 822A

# COUNTRY FRA

# CONTRIBUTOR University of Hawaii Sea Level Center

# CONTRIBUTOR WEBSITE https://uhslc.soest.hawaii.edu

# CONTRIBUTOR CONTACT philiprt@hawaii.edu

# ORGINATOR Systeme d’Observation du Niveau des Eaux Littorales (SONEL)

# ORIGINATOR WEBSITE Unspecified

# ORIGINATOR CONTACT Unspecified

# LATITUDE      48.38300000

# LONGITUDE     -4.49500000

# COORDINATE SYSTEM Unspecified

# START DATE/TIME 1846/01/04 00:00:00

# END DATE/TIME 2018/12/31 23:00:00

# NUMBER OF YEARS 165

# TIME ZONE HOURS 0

# DATUM INFORMATION Unspecified

# INSTRUMENT Unspecified

# PRECISION Unspecified

# NULL VALUE -99.9999

# GAUGE TYPE Coastal# OVERALL RECORD QUALITY No obvious issues

#

# CREATION DATE UTC 2021/11/01

#

# COLUMN 1 Date yyyy/mm/dd

# COLUMN 2 Time hh:mm:ss

# COLUMN 3 Observed sea level (m)

# COLUMN 4 Observed sea level QC flag

# COLUMN 5 Use-in-analysis flag (1 = use, 0 = do not use)

#

# Quality-control (QC) flags for column 4

#

# 0 – no quality control

# 1 – correct value

# 2 – interpolated value

# 3 – doubtful value

# 4 – isolated spike or wrong value

# 5 – missing value

#