Following the discussion between Delft Hydraulics and CEH & Wallingford Software on Friday 2 May 2003 in Wallingford on providing an enumeration of quality flags as a part of the SIS, a proposed quality flag enumeration is given in the table below. As described in the timeseries XML schemas provided we have made allowance for a single quality flag. This is contrary to the EA XML interchange formats which provide for three separate quality flags. A single flag seems more appropriate to the level of communication we are dealing with and should avoid ambiguity. The flags are single byte values and are incorporated in the XML Schema for time series. Quality flags are provided for each data point.
Quality flags are constructed on a philosophy of two qualifiers. The first described the origin of the data and the second the quality.
Possible origins of data are:
1. Original: This entails the data value is the original value. It has not been amended by NFFS
2. Completed: This entails the original value was missing and was replaced by a non-missing value.
3. Corrected: This entails the original value was replaced with another non-missing value.
Possible qualifiers are:
4. Reliable: Data is reliable and valid
5. Doubtful: The validity of the data value is uncertain
6. Unreliable: The data value is unreliable and cannot be used.
Following this specification, the table below gives an overview of quality flag enumerations
Table D.1 Enumeration of quality flags
Enumeration |
Description |
|
0 |
Original/Reliable |
|
1 |
Corrected/Reliable |
|
2 |
Completed/Reliable |
|
3 |
Original/Doubtful |
|
4 |
Corrected/Doubtful |
|
5 |
Completed/Doubtful |
|
6 |
Missing/Unreliable |
|
7 |
Corrected/Unreliable |
|
8 |
Completed/Unreliable |
|
9 |
Missing value in originally observed series. Note this is a special form of both Original/Unreliable and Original/Reliable. |
Notes:
|