To Find the Highest Mountain (in Botswana)

It's not as easy as I thought it would be...

Aug 29, 2024

I’m back in Gaborone and feeling fine, thank you for asking. I’m taking a little break from the book to work on another project that’s caught my fancy. It turns out nobody knows what the highest mountain in Botswana is. There are three contenders: Otse Hill (1,491 meters), Monalanong Hill (1,494), and the tallest of the Tsodilo Hills, known as the Father Hill, (1,489). But those measurements are from Shuttle Radar Topography Mission (SRTM) data, and the margin of error is something like 16 meters.

Ouma, Puso, and me, University of Botswana, Gaborone, July 27, 2024.

So I emailed a geology professor at the University of Botswana, Boipuso Nkwae, to ask him if he had any advice on the best way to find out which is the tallest. Well, he went above and beyond the call of duty, inviting me to campus to meet with him and another geology professor, Yashon O. Ouma. Puso and Ouma, as they asked to be called, spent more than thirty minutes explaining the ins and outs of mountain measuring. It was essentially a free course in surveying! What they told me boiled down to this: I can either rent time on a satellite to collect topographic data and then have that data processed—which would cost a fortune—or I can climb to the top of each hill with survey-grade GPS equipment, which would cost slightly less than a fortune, assuming I could rent or borrow the equipment.

How to Measure a Mountain 101, courtesy of Puso and Ouma.

On Thursday (August 29), I stopped by the Botswana’s Department of Survey and Mapping in Gaborone to ask if anybody there knew how I could find the highest mountain. I was eventually escorted into the office of Mr. K. Selome, who explained that the data they have available probably isn’t precise enough to answer the question, but he told me how I can check, just to be sure. The maps the government produces are contour maps, which don’t measure vertically with the precision required for my purposes.

I thought the mannequins in the front of the building were a fun, quirky touch.

So, unless somebody out there has satellite time they’re willing to give me, it seems the only way to find out which hill is the tallest will be to get some sophisticated equipment, find somebody who actually knows how to use it, and convince that person to climb to the top of each hill with me. I will keep you all posted on my progress, and am always open to suggestions on how to proceed!