selection in draw graph

by Nate Hekman on December 3, 2007

Graphing of results in CONTOUR was really showing its age in GeoStudio 2004.  In fact it had hardly changed since SEEP/W version 1 way back when Windows was first released, other than adding additional parameters you could graph.

I’m excited about how the graphing feature has changed in GeoStudio 2007.  I’ll take the next couple of weeks to describe it, but I’ll start this week with describing how you select data to graph, to continue the selection theme (see “selection in keyin lists“, and “mouse selection“).

Data Source

When creating a graph, one of the first things to do is to select where you want the data to come from.  You can graph data from nodes or gauss regions, convergence data, or other sources depending on what kind of analysis you’re performing.

The “Data from” selection

We’ll just take a look at Nodes today because I want to describe how to select nodes.  The other data sources generally don’t have any selection at all, or let you select from a list.

Set Locations

After picking “Nodes” you need to choose which nodes.  We call that the “Location” of the data, so you click the “Set Locations…” button.

The Graph window disappears to clear up room for you to select on your drawing, and is replaced by a smaller box.

The “Set Locations” dialog box

Here you can choose whether you want to select “Geometry Items” or “Custom Locations”.  “Geometry Items” is the simplest–it lets you pick regions, lines and points.  “Custom Locations” is the most powerful, letting you pick any coordinates you want.

Geometry Items

To pick geometry items, you use the same selection techniques we discussed last month:

  • Click on any point to select it.  The data will come from the node under that point.
  • Click on any line to select the entire line.  The data will come from each node under the line.
  • Click on any region to select the entire region.  The data will come from each node in the region.

And of course all the multi-selection techniques work too:

  • Drag a rectangle and any points, lines or regions fully contained in the rectangle will be selected.
  • Hold down Shift and click twice and any points or lines between the two clicks will be selected.
  • Hold down Ctrl while selecting something and it will be added to the current selection.
  • Hold down Ctrl and click on something already selected, and it will be removed from the selection.

Custom Locations

What if you want to graph data from a specific coordinate but there’s no point there to select?  Maybe not even a node?  Or what if you want graph along an arbitrary line, but you want to experiment with different mesh configurations?

Enter Custom Locations.

Custom Locations de-couple graphing from how the geometry is defined.  You can pick any point, line, rectangle, or combination thereof.  If a node exists at the location you want, the graph will use data computed at the node.  If no node exists data will be interpolated from the nearest nodes to get a reasonable estimate.

  • Click anywhere to graph at a point.  If you’re near (within a few pixels) a node, the node will be selected, otherwise the graph will interpolate from the nearest nodes.

Selecting an arbitrary coordinate

  • Hold down Shift and click two coordinates to graph along a line.  The graph will contain data for every point where your line crosses an element edge or a node.

Selecting an arbitrary line in space

  • Drag a rectangle.  The graph will contain data for every node in the rectangle.

Selecting an arbitrary rectangle

And again you can use the multi-selection techniques to combine the above.  Hold down Ctrl while clicking, shift-clicking, or dragging a rectangle and the new locations will be added to the existing ones.

Multiple selection

When you’re done selecting where data will come from, click the “Show Graph…” button to go back to the main Draw Graph view.  I’ll look more at what Draw Graph can do next week.

{ 4 comments… read them below or add one }


Alice Mason 11.17.08 at 12:46 pm

I am new to using Geostudio, in particular seep/w which I have just started using for a university project. I have the problem that although the contours and toolbar say that my pore water pressure is changing over time the graph function plots no change pressure for selecting a given node and pore water pressure v’s time. What am I doing wrong?


Nate 11.17.08 at 3:29 pm

Hello Alice. Welcome to SEEP/W. 🙂

The contours can only plot changes in pwp over distance, not over time. Contours show the state at a single “snapshot” in time. I’m not sure what you mean by the “toolbar” showing a change of pwp over time. If the graph shows a constant pwp over time for a particular node, I’m prone to believe it. You can double-check it by using the View Result Information command, click on the same node, then use the Time dropdown in the toolbar to change time steps and look at whether the values at that node change.


Alice Mason 11.17.08 at 3:40 pm

Thank you for the quick response. What I meant by the toolbar bit was, I was using the time drop down toolbar to look at the pwp for different sections of time and using the contours to see what the pwp was at each time frame. The pwp read from this did not respond to the graph. This is made more obvious by a dramatic change in the contours over the time period which does not appear to be picked up by the graph. This is what confused me.


Nate 11.17.08 at 3:42 pm

Hmm, that doesn’t seem right. Can you email me your file? I’d like to take a look.

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