topic Re: Slope Tool for Bathymetry in Data Management Questions

Slope Tool for Bathymetry

MShairah — Sun, 20 Nov 2022 05:10:54 GMT

Hello!

I was wondering if the Slope Tool can be used for bathymetry points (negative elevation values) ? What would the slope values look like? I was unable to find any related tool in the Bathymetry Toolbox.

Thank you.

Re: Slope Tool for Bathymetry

DanPatterson — Sun, 20 Nov 2022 10:35:47 GMT

You could always do a comparison to understand first hand.

First calculate slope using the original elevations/depths.
Second take the absolute values of the inputs to make the inputs positive, then calculate slope.
Take the difference between the two slope rasters.

What do you see?

Re: Slope Tool for Bathymetry

MShairah — Thu, 24 Nov 2022 06:56:32 GMT

Hello Dan,

Thank you for your response. I've done as you suggested and these are the results. The green areas (low slope) are more or less the same for both rasters. However , the red areas (slope values greater than 10) are more pronounced and cover a bigger area when using the absolute value of the depths. I wonder why this is so.....

Re: Slope Tool for Bathymetry

DanPatterson — Thu, 24 Nov 2022 10:01:41 GMT

Your mins and maxs are different. check that your raster properties were the same eg. raster type, cell size, alignment etc were the same and you may have to fine-tune your classification.

Also, subtract the two ... that is where you will see the differences and their magnitude