open TELEMAC-MASCARET The mathematically superior suite of solvers

I did a little googling... it seems that, according to a comment from 2016, this is a defect in the way that the ASC file is being written. See https://gis.stackexchange.com/a/192294

Ok. I'm in agreement with adding something into Blue Kenue to be able to override an incorrectly written ASC file header.

Stay tuned...

Kindly,
Alan

Notice that the ArcGIS Help 10.2 documentation clearly defines what xllcorner and xllcenter are supposed to do.

So, if I add an override, then people will have know that their header is incorrect and that such an override needs to be applied.

ok... reading the documentation is helping me to understand what is going on

First, Blue Kenue is wrong and needs to be fixed according to: this link

And I quote:

Hi!

Thanks for the googling.
We arrived to the same conclusion I think. A dialog box asking for overriding or not seems the best choice I think?

Kind regards
PL

The way I understand it, no dialog is needed because the values in the ASC grid must be for CELLs. So... Blue Kenue is wrong.

I'll create a new alpha this afternoon (today) and you can try it out... after I add something into the Blue Kenue reference manual about this.

I'm glad that you kept on persisting with this point and I apologize that it has been incorrectly implemented in Blue Kenue for so long!

Kindly,
Alan

No problem!
It will be very nice to skip do the manual shift!

PL

Using your example + one of mine for "center", this is now what is imported into Blue Kenue. I believe that is now the correct interpretation. I'll add this image into the Reference Manual too.



Kindly,
Alan

Probably this image is more clear for people. The ASC grid is the coloured bit, while the black dots are what is being imported into Blue Kenue. Blue Kenue is treating the black dots as a 2D Rect Scalar; hence the reason why interpolation can occur when using Blue Kenue.



Kindly,
Alan

Shoot... that visualization isn't quite right. AND changing the Rendering to "Fill Square" also isn't quite right. I will have to add another rendering type. I'll call it "Raster" to help make the rendering more clear.

Stay tuned...

Kindly,
Alan

Ok... I've added a new "Rastor" rendering for 2D Rect Scalar objects (and an ASC grid is imported into Blue Kenue as this type).



LEFT: A wireframe that is drawn from point to point. For an ASC grid this means from the center of the CELL to the center of the next CELL.

RIGHT: The point is centered on a CELL and a square (rectangle) is drawn around it based on the CELL's size. Therefore, the right image will be larger than the left image by 1/2 CELL width + 1/2 CELL width = 1 CELL width.

Kindly,
Alan