Groundwater hydrology and groundwater simulation model, models, modeling, modelling software
Tabular Observation Point Files
Observation points are used for model calibration. Observation points can be created one at a time using the Create Point tool and the point attributes can be entered using the Attributes dialog. However, for sites with large numbers of points, this type of entry can be time consuming. In such cases, it is more efficient to organize the observation point data in a spreadsheet, export the spreadsheet as a text file, and import the points using the Import command in the File menu or through the Import button in the Coverages dialog. If an observation coverage already exists and is the active coverage, the points are added to the coverage. Otherwise, a new one is created. Once the file is imported, the Observation Coverage Options dialog appears and the general options for the coverage can be established.
Observation point data are imported using two files. The first file is the observation point file and it defines the locations of the observation points, the measurement types, and the confidence intervals. The second file defines the measurement types that are transient. The second file is not required for steady state observations.
Observation Point File
Before importing the observation point file to GMS, the file extension should be changed to *.tob. When importing files, GMS determines the file type from the three character extension. The file should be formatted as follows:
NODATA value
"name" "x" "y" "z" "layer" "mtype1" "int" "conf" "mtype2"...
"name" x y z id val1 int2 conf1 val2...
Sample tabular observation point file:
NODATA -999
"name" "x" "y" "z" "layer" "head" "int" "conf"
"OBS Q5" 234.3 44.2 323.2 1 567.5 1.2 95
"OBS Q6" 833.3 842.3 320.2 1 555.3 1.4 90
"OBS Q8" 855.3 898.3 322.2 1 -999 0 0
The file can be delimited using spaces, tabs, or commas. The items in the observation point file are as follows:
NODATA Record
The NODATA record is an optional record used to list a key value which is used to flag values which where not observed. For example, if a NODATA value of -999 is listed and one of the observed values in a measurement type column has a value of -999, the value is assumed to be not observed at that point. This is equivalent to turning off the Observed toggle in the Observation Point Attributes dialog.
Name Column
The name column is an optional column used to list the name or id of each point. If the column is missing, GMS will assign a default name to each point. For example, the first point would be named "point_1" by default. If the column is present, it must begin with a column header of "name" (case insensitive). The quotes on the column header are optional. The quotes on the point names are also optional but must be used if the name contains spaces.
X, Y, and Z Columns
The x, y, and z columns are required columns and should be used to list the coordinates of each point. The quotes on the column header are optional.
Layer Column
The layer column is an optional column which can be used for points associated with 3D grids. Each value in the column must be an integer. The layer id's are used to list the layer of the 3D grid each point is to be associated with. If this column is missing for a 3D grid, GMS uses the elevations of the points (z values) to determine the appropriate layer. If the column is present, it must begin with a column header of "layer" (case insensitive). The quotes on the column header are optional.
Observed Values Column
After the layer column (or the z column if the layer column does not exist), a column of observed values may be listed. The column header provides the name of the measurement type. The values should then be listed in the column. The NODATA value may be used to signify an unobserved value as explained above. Quotes must be used on the column header if it contains spaces but are optional otherwise.
If the observation point file is being used in conjunction with a transient data file, a dummy value may be entered for the observed value.
Interval and Confidence or Standard Deviation Columns
After the observed values column, the calibration target should be specified using one or two columns. If the interval and confidence option is used, two columns should be listed. The column header for the first column must be "int" and the column should contain the interval. The header for the second column must be "conf" and the column should contain the confidence values (0 - 100). If the standard deviation option is chosen, only one column should be listed. The column header must begin with the letters "st" and the standard deviation values should be listed. In each case, the quotes on the column names are optional. The quotes should be used if the name contains spaces.
Multiple Measurement Types
If multiple measurement types exist, they should be listed in subsequent columns using the value-interval-confidence or value-std. deviation sequence described above.
Transient Data File
The transient observation data file should only be imported after the associated observation point file has been imported. The transient data file contains transient observed values for the points defined in the observation point file. The transient data file has the following format:
"name" "date" "time" "head"
"OBS Q5" 12/3/1999 18:00:00 238.5
"OBS Q5" 1/30/2000 7:38:25 834.7
"OBS Q6" 3/27/2000 18:00:00 878.3
"OBS Q6" 12/3/1999 18:00:00 733.2
"OBS Q6" 12/5/199 14:48:32 838.2
&ldots;
The name column must be included. This tells GMS how to link the transient observation data to the points in the observation coverage. The dates use the MM/DD/YYYY format.
The last column in the header line defines the name of the measurement type. This measurement type should be marked as transient in the Observation Coverage Options dialog after the first file is imported.
As each line is imported, the matching observation point is found and the observed head is added to the time series for the point.
This file should have the extension *.tof. The file is imported through the Import command in the File menu or through the Import button in the Coverages dialog. When the file is imported, the active coverage must be an observation coverage.
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