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Note:
Extraction of longitudinal profiles is not available for irregular grids, points and polygons. The profile sketch will be erased when switching to a plot that contains data of one of these data types.
Note:
If longitudinal profile data is displayed in the spatial display, then there is no need to draw a profile sketch. Just press the F2 key or right click and select 'Show Profile' from the pop-up menu to show the graph of the profile.
Extracting data for an area from a grid time series
It is possible to extract time series data for a specific part of a grid and show this in a separate graph. The specific part of the grid is defined by drawing an area sketch (a closed polygon surrounding the desired area). Start drawing an area sketch either by right clicking and selecting 'Start Drawing Area' from the pop-up menu or by Shift+left clicking on an edge for the desired area. A coloured dot will be drawn to indicate the selected point. Add additional line segments along the edge of the desired area by left clicking in the display. Finish drawing by double-clicking. The last point in the sketch will be connected to the first point automatically to create a closed polygon that surrounds the desired area. Each grid cell inside the area is marked with a green dot.
Once an area sketch has been drawn, extract the desired data by right clicking and selecting one of the following options from the pop-up menu: 'Show Volume Summation', 'Show Area Times Average Level' or 'Show Area Mass Balance'. The corresponding graph will show automatically.
- Volume Summation: shows the sum of the values inside the area. This uses all grid cells that are (partially) inside the area. The value of each grid cell is weighted using the fraction of the grid cell that is inside the area.
- Area Times Average Level: shows the average level inside the area multiplied by the size of the area. This uses all grid cells that are (partially) inside the area. The value of each grid cell is weighted using the fraction of the grid cell that is inside the area.
- Area Mass Balance: shows the net horizontal flow into/out of the area. This uses all grid cells that are for at least 50% inside the area.
The 'Area Mass Balance' option is only available for grids that contain horizontal flow data in the form of u,v vectors. The 'Volume Summation' and 'Area Times Average Level' options are only available for grids that contain scalar data (e.g. water levels or rainfall data).
To extract data for a different area just start drawing another area. This will erase the previous sketch. The area sketch can also be erased by right clicking and selecting 'Delete Sketch' from the pop-up menu.
When animating the grid display, a marker will move over the time series graph as well. Note that the same area sketch can be reused when switching to another plot (right clicking and selecting one of the relevant options will open a new window).
Note:
Even more essential then for scalars, it is wise to pause the grid animation when dragging an area for extracting data.
Note:
Extraction of data for an area is not available for irregular grids, points and polygons. The area sketch will be erased when switching to a plot that contains data of one of these types.
Note:
The green dots only mark grid cells of which the cell centre is inside the area. The actual calculations also use grid cells that are partially inside the area.
Setting the display time
The display time in the spatial display can be changed in the standalone system only . The use is similar to the setting the display time in the data display, but with less modification possibilities.
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