Surface Parameters Tool (Spatial Analyst)

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05-21-2021 12:07 AM
JoanaWiese
New Contributor II

Hi all,

I am working on an analysis on Mars using MOLA MEGDR gridded raster datasets with a horizontal resolution of 300 m along-track and 40 cm vertically. 

I want to apply the Surface Parameters Tool (Spatial Analyst) to determine areas of convex curvature and steep sloped on selected mountains in the South Polar region. My raster data is in a planetocentric coordinate system based on the IAU2000 catographic standard and in ArcGIS Pro I use the Mars2000 geographic coordinate system with a custom Albers Equal Area projection of my 2D map.

In the description of the Surface Parameter Tool it states that the tool performs all its calculations in a geocentric 3D coordinate system—also called the Earth Centered, Earth Fixed (ECEF) coordinate system. Which for my application on Mars might result in conversion errors and inaccurate outputs.

1. I was wondering is there are some guidlines how this tool can be used on Mars, specifically how I can avoid that this internal coordinate tranformation to ECEF affects my results and whether I can make it an Mars Centred Mars Fixed system for the calculations.

2. The input surface needs a vertical unit and my raster elevation data have meters as vertical unit stated in the source. Nevertheless, the tool complains that the input raster dataset does not have a vertical unit defined and I was wondering why this is happening. Even when I use Define Projection to specify a vertical coordinate system for the data it complains.

I am thankful for any tips or references on using ArcGIS Pro on Mars.

I am working in ArcGIS Pro 2.7 on a Windows 10 operating system. More info on the MEGDR data can be found here

Best wishes,

Joana 

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1 Reply
Steve_Kopp
New Contributor

Regarding use on Mars, it should be correctly using the a and b axis lengths of the Mars coordinate system you are using. We'll revisit the doc to make it clear this is designed to work with any coordinate system regardless of planet.

Steve

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