Jump to content
TUFLOW Forum
paulevano

Depth Grid Comparision

Recommended Posts

Dear all,

I have been asked to run a sensitivity run using a smaller grid (4m) to assess the difference in flood extents against the original grid (10m). The model is a relatively large tidal model which has been run both with and without a breach in an earth embankment.

I would like to compare the difference in flood extents using the grid difference batch file, however, when I run this an error message occurs (see attached) stating that the ASCII grids differ.

Does anyone know how to compare two grids of different sizes?

Cheers,

Paul

Share this post


Link to post
Share on other sites

Paul

You could import the peak water level grid for both cases into MapInfo (Vertical Mapper), and use Vertical Mapper to calculate the difference between the two grids.

Share this post


Link to post
Share on other sites

Hi Paul

Yes, often easiest to use something like Vertical Mapper to subtract two grids of differing size. There are also lots of other options for analysing multiple grids.

You may have already done this, but when you create the .asc grids using TUFLOW_to_GIS use the -grid option with the same grid size (eg. -grid5). The two grids will have to have the same origin and dimensions (this information is at the top of the .asc file if you need to check this).

Cheers

Bill

Share this post


Link to post
Share on other sites

Hi,

I created a difference grid using asc to asc.exe utility. Wiki says that if any of the input files are having NULL values, then the difference grid will take NULL value. Thats not right is it?

The difference grid should not return NULL right. While comparing Baseline scenarios with proposed scenarios, it gets difficult to justify the existence of NULL values, when there has to be either a postive or negative value.

 

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...