Velocity magnitude comparison between two models

I have run two models and I’m currently using the ViewGrid function to compare water elevations and bed shear stress between the two models. I would also like to compare velocity magnitude in each cell; however, when pressing Alt-M the velocity vectors for my compare model only show up. The velocity magnitudes of my compare model are not subtracted from the velocity magnitudes of my base model. I’m using EE 5.0 and this might be an issue because I’m using an older version. As I only have a manual for EE 6.0 I have not been able to confirm if this function is available in EE 5.0.

Please let me know if a velocity magnitude comparison can somehow be done in EE 5.0?


Hi Michael,

Currently it is not possible to compare the velocity magnitudes when comparing models in EE up to EE7.0. You can compare the velocity vectors as an alternative. However, comparing actual magnitudes is something we may consider for a later release of EE.


If you are interested to see the velocity distribution difference of the two models, you can do so using R. First of all, what you can do is to export the velocity magnitudes of one model and then velocity magnitudes of another model. Then you can compute the magnitude difference of these two models in an spreadsheet. You can find out how much difference is there. If you want to make a plot of the net velocity distribution then you can use mapping tools in R. The graph will look great. You will need the shapefile of the area and the velocity magnitude.

I don’t know whether you want to put extra effort on this thing or not. If you want to proceed, let me know I can offer more suggestions.


Hello John,
Thanks for the info. I’m having some difficulty exporting all the velocity data from the ViewGrid function. The xyz extraction tool seems to be limited to manual extraction, and as my model is quite large, that’s really not an option. Is there a way to select all the data and export them into a txt, csv or xyz file? I’m using EE 5.0.


Hello Michael,

I am not sure whether this procedure works for version 5 or not.
1) Go to View Plan
2) Under Viewing Opt’s select Velocities
3) Under Velocities just select Magnitudes
4) Go to Extract X, y and current value using mouse or Point
5) Model extraction tool opens and then you have 3 options.
6) Choose option 3rd i.e 2- Load Existing IJ Data file
7) Enter value 2 on the Model extraction tool
8) Then choose your lxly file when it asks for a Load IJ Data file
9) At first you may not see your lxly file, you may need to change the extension filter from IJ Filex(.dat) to All Files (.*), then select your lxly.inp
10) After you select lxly file, you will notice that model will automatically extract the velocities from all the cells. Then on the top of the viewplan window, you will see information from XY Extract tool i. e Read and extracted x points using current view settings !
11) Click on the model extraction tool again to save your extracted results to the file of your choice.

I think if you follow my instructions it should work .

Good luck.


This method works great. Much appreciated!



I am glad that it worked for you.