I found myself revisiting photos from a 2009 Grand Canyon trip when I had an early point-and-shoot digital camera. I got a dozen or so good photos of flora and fauna that I would like to upload to iNat. I had a really good map atlas of the whole 220- mile trip and kept enough notes to figure out where the photos were taken, some to the near-exact river mile. But I don’t think I can come up with lat/long coordinates on the location maps in iNat without hours of cross-checking. Is there any way I can make these observations usable with just river miles?
(I’m contacting a couple people who may know.)
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If you go to the actual maps.google.com website, it has a distance ruler function in the (right click) context menu that you could use to trace your way down the river with. If you do that and supply the locations with an accuracy circle to match your confidence, that’s probably a much better result than not having those obs posted :)
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I don’t have GPS. I use satellite view as my default for iNat maps.
Yesterday for a Kirstenbosch upload, I can see that actual plant on the map!
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This could be done in GIS by plotting points along the river course which cumulate the distance and then using your river miles to match/interpolate the coordinates. River lines might suffer from the coastline paradox but you could use the relative distance based on your starting point, end point and total distance (according to your reckoning).
Same thing I do!
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I think if you are close and don’t just put everything as “Grand Canyon” they are still valuable. Probably the most important things in that particular situation are that you get the SIDE of the river correct (some things are only found on one side or the other). Elevation is something else that is important in that canyon, so as long as you can get close to the actual distance from the river then you’re probably fine. What will create more of a challenge (meaning less helpful) is if you have an “accuracy” bubble that is so large that it incorporates both sides of the river or the entirety of the area below the rim.
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None of my actual cameras have GPS (and if they did I’d leave it off as that drains batteries fast), so I do most of my observation placing using the map instead. I have a pretty good spatial memory, but even for folks who don’t have that kind of mind it’s usually not difficult to get close enough to be useful using the map and the memories the photos trigger.
If you’re feeling uncertain about any of them, add a note in the description portion when you post saying something like, “Uncertain about exact location, but was on X side of the river before/after/next to/near Y landmark.”
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Aren’t river miles standardized values established by some agency?
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I’d think the rafting companies that run the Grand Canyon have the lat-long for each river mile segment. You might be able to contact one and get that info. There are also regular fisheries surveys there by Fish & Wildlife or their contractors and I’d bet they have the same. You might have to do some internet searching to find the right contacts.
See: https://grandcanyon.usgs.gov/portal/home/item.html?id=ce7a7c62bb0c401c87fd8cc7bf64085b
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For the Grand Canyon/Colorado River they are. Here’s one of the USGS river mile maps. This one is marked every 20 miles, but hunting around there are others that are marked tighter.
And a few years ago the Grand Canyon Trust came out with a nice new map of the region, but I don’t know if it’s still available.
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For many years I have used the technique of carrying a small GPS logger while taking photos and using a geotagging utility like Picmeta Phototracker to set the set the coordinates in the image from the GPS data. It works by matching the photo time to the time on the GPS track so your camera clock needs to be fairly accurate.
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Thank you but I can’t see how this would work in practice, mainly because the section of the river that we floated was 220 miles long and it meanders back on itself in myriad loops. I’m not sure it would be worth it for a just a dozen or so observations! But I’ll take a look and see if I could make that work.
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Diana, I’ll see if I can make that work. I usually use satellite view too, but the river section we floated is 220 miles/354 km and it all pretty much looks the same when you drill down. I mean, I can pick out a few landmarks on the river, like some of he major rapids and side canyons, but it’s hard to distinguish most of the tiny sandbars where we camped and where I took photos.
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Hi pdwhugo, welcome to the Forum and thank you for your input! jnstuart, in a comment below, provided a link to this very thing from the U.S. Geological Survey. it might work for what I need.
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Thank you for your input, petezani! I don’t have that many observations but I do remember, for most of them, whether I was on river-right or river-left. Elevation, I’m not sure; most were at or close to river level but some were on hikes. It’s funny you should mention this because I’m 3/4 through a great book, “Brave the Wild River” (Melissa Sevigny 2023) about 2 women botanists who ran the river in 1938. They recognized that slope, aspect, and elevation of the plants they collected were all important variables. The plants they pressed are housed in several major herbaria in the U.S. As to the accuracy bubble, I often wish it could be a rectangle instead of a circle!
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This map might work for my situation – thanks for the link! It’s still going to be a challenge but I’ll try a couple of observations (the easy ones, at obvious landmarks). Then I’ll report back (might take me awhile, though).
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Yes that link of @jnstuart has done all the work already, the miles and coordinates are tabulated in the file. So for example:
- Mile 0 = 36.864880056313204, -111.58786147269528
- Mile 10 = 36.751386720288174, -111.67516720573164
Etc. The table has 297 entries from mile -15 to 281. Does that cover your trip?
It also goes into fractions of miles but if your best estimates are whole numbers then this would work fine, with an accuracy circle of 1 mile I suppose.
I can convert the file to a different format or if you share the list of miles you need information for I can just send you the output?
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The tool lets you measure multi-segment distances along complex shapes by adding as many vertices as you like. So it might take you 200-odd mouse clicks to trace the centerline of the river from your starting point, but that still seems like a job that ought to take minutes instead of hours, and will give you distance marks all along the route you traced.
I’ve used it to measure river and trail lengths before. The biggest inaccuracy probably comes from how well the satellite images are mapped onto their actual locations to place the waypoints.
But that said, if there is an existing easy to use source mapping the mile posts to locations, as someone has since indicated - that’s probably the easier and more accurate way.
Sounds like a good use case for a cone-shaped accuracy bubble: I know it was on this side, but not exactly where on this bank, so I place the point of the cone at the center of the possible area and expand it inland from there.
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