View source for Tutorials:6 Visualizing Stream Data

'''This tutorial is compatible with:'''
* '''WMS Version 8.1 and later'''
* '''GSSHA Version 3.0b and later'''<br><br>
<font color= "red">'''Disclaimer: GSSHA tutorial exercises do not represent real world conditions'''<br><br></font>

While the streams are connected to the overland flow plane they are separate models each having their own input files and data formats. The streams output data in a format is called the link/node data set format. These files hold a data value for every link and node at the same time step as that for the gridded output data. The two most common files in this format are the channel depth file (*.cdp) and the channel discharge file (*.cdq.)

The link/node data set files are read in with the other solution files and the data tree will place a reference to them in the solution folder under the 2D grid. Since they are not data to be visualized on the 2D grid there are a couple of steps to visualize the data. The link/node data sets are visualized on a TIN. The TIN is made from the stream arcs and the stream boundaries around the streams. The process of making the TIN also copies the link/node data sets to the TIN.

To make the TIN, a solution set must be in memory that has valid link/node data sets. If you are just starting this lesson:<br><br>
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	<li>In the 2D Grid module [[Image:Icon_2DGrid.png]] select GSSHA™ | Open Project File…</li>
	<li>Browse to the Finished_tutorial\streams_trap folder.</li>
	<li>Select the streams_trap.prj file and select Open.</li>
	<li>Select GSSHA™ | Run GSSHA™ and select OK to run the simulation</li>
	<li>After GSSHA is finished running click on the Close button and the solution will be read</li>
	<li>Verify that GSSHA™ has finished running and that the '''Read solution on exit''' toggle is checked.  Click the '''Close''' button to close the run and read the solution.</li><br>
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If you expand the streams_trap solution in the 2D Grid folder you’ll see a Depth data set as well as the summary file. We can look at the Depth file using the methods in the second chapter. You can also see the Stream Depth and Stream Flow data sets in the 2D Scatter Data folder.  The Stream Depth and Stream Flow data sets are stream link/node data sets.
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In order to visualize these we need to turn on the contours for the 2D Scatter Data.
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	<li>Select either the Stream depth or the Stream flow data set in the 2D Scatter Data folder in the data tree</li>
	<li>Open the Display Options dialog.</li>
	<li>Turn on the contours for the 2D Scatter Data.</li>
	<li>Select a radius and Z Magnification (try a radius of 50 and a Z magnification of 50).</li>
	<li>Click OK.  Select a time step other than the first one in the ''Properties'' window.</li><br>
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You should be able to see colored circles along the stream links. The color represents the value of the data point. If you rotate into 3D mode, you will see that the circles are actually the tops of cylinders. In the properties folder you will see the time steps. As you select individual time steps the data for that time step both the 2D grid data and the 2D scatter data will be contoured. If you switch to the 2D grid module, you can select Data | Film Loop... and create a film loop of the stream and grid data.
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