Showing posts from October, 2019

Streams of Tennessee

Longest Stream Segments Between Confluences All of the longest stream segments between confluences occur in areas of karst topography, interestingly enough. The implication is that there are actually other streams and confluences, but are underground as cave streams and springs, neither of which would appear in the National Hydrographic Dataset. Part of this 1) Calfkiller River†, White County , 12.12 miles 2) Collins River, Warren County , 10.69 miles 3) Falling Water River, Putnam & White County , 10.59 miles 4) Blackwater Creek, Hancock County , 10.23 miles 5) Duck River, Maury & Marshall County , 10.12 miles 6) Big Sycamore Creek, Claiborne & Hancock County , 10.03 miles 7) Hurricane Creek, Rutherford & Wilson County , 10.02 miles 8) Happy Creek, Sevier County , 9.53 miles 9) East Rock Creek, Marshall County , 8.82 miles 10) War Creek, Hawkins County , 8.56 miles †Calfkiller River is more likely 13.23 miles since the "confluence" measured

Loading Data into Locus Pro

Every TAG caver knows that Locus Pro is the best GPS program for you mobile device (sorry iPhone users it's only for Android). Locus Pro easily handles the ten thousand plus data points for the Tennessee Cave Survey's dataset of cave entrances, and can simultaneously display several other hefty datasets atop it. I'm running a Pixel 3 and it runs quite smoothly. So you've got a dataset, maybe it's the new TCS distribution, or maybe it's some other KML or GPX file and you want to load it to Locus Pro. Here's how you do that. We start with the screen above. My layout may be different than yours, so if it's unfamiliar don't sweat it. We're looking for the Data menu. Above I've circled its icon in red. You can also get to this menu by pressing the three bars in the upper left and going to Points . Your Data menu should look something like the above, perhaps without all the lines and the weird mosaic blur (don't ask). I can

Spring Creek Gorge

Spring Creek Gorge begins at Upper Waterloo Falls ( 36.302529,-85.475847 ) and ends at the confluence of Spring Creek and Roaring River. It's a rugged stretch of river best negotiated via canoe or kayak when the water is high enough to run. In other parts of the year, people access the gorge by alternating hiking and floating on inner tubes. Numerous cascades and waterfalls can be found along the course of Spring Creek as it drops down into the Nashville Basin. The map above shows in detail the path of Spring Creek, a designated State Scenic River, and the locations of its many waterfalls. Access to the gorge is through private property. An access easement appears to still exist, though access to Upper Waterloo Falls is now prohibited unless one comes in from Waterloo Rd before the bridge. The access easement hinges on respect of the land. Periodically it's necessary to clean up after the idiots who party there and trash the parking area and around Waterloo Falls. H

Creating a Noise Profile and using it as a Mask in Photoshop

I have a bunch of old photographs which are very noisy, but are still of interest to me. In the reprocessing of these images with better tools and a better eye I've developed a simple way to create a mask to apply noise smoothing to a portion of the image. My goal is to create the following image. Click the image to load its Flickr page and click the image again to magnify it. It's not a perfect image, but the noisy parts of the image have been smoothed, and the parts of the image which aren't noisy haven't been, which allows them to retain their detail. What I am calling the noise profile is simply the difference between the original image and a noise reduced version of the image with a little bit of modification. If you would like to follow along, find an image of your own with noise in it. I'm using the latest version of Adobe Photoshop CS for the PC (10/25/2019). First, let's load our image. Here's what mine looks like. I usually start by

Big Tennessee Sinkholes

Tennessee has perhaps millions of sinkholes, most of which are very small features. Based on data analysis from a 2013 sinkhole study (Dunigan/Sutherland 2013) I provide here a list of some of the largest features by dimension in the state. Below you'll find an interactive map, a table with this information, and photographs of some of the sinkholes. * No official place name, named for nearest GNIS feature if nearby. ** Multiple possible names for feature. Made best guess. Excluded from these lists is Montlake in Hamilton County. It may fit on the volume or depth list, but I cannot easily get at that information since it is flooded. It is a truly spectacular feature. More about Montlake here .

Delineating Sinkholes in GIS

A sinkhole, also known as a cenote, sink, sink-hole, swallet, swallow hole, or doline (the different terms for sinkholes are often used interchangeably), is a depression or hole in the ground caused by some form of natural collapse of the surface layer. Most are caused by karst processes – the chemical dissolution of carbonate rocks or suffosion processes. Sinkholes vary in size from 1 to 600 m (3.3 to 2,000 ft) both in diameter and depth, and vary in form from soil-lined bowls to bedrock-edged chasms. Sinkholes may form gradually or suddenly, and are found worldwide. Above language is borrowed and slightly modified from the Wikipedia page for Sinkholes. In order to have a tutorial showing my methods for delineating sinkholes, I'll need to define some vocabulary. This vocabulary isn't intended to replace any existing definitions so much as to clarify the context in which I'll be using them. Sinkhole : A closed depression through which water can only escape through