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Re: Amazing picture of Half Dome?

Posted: Wed Mar 11, 2009 1:16 pm
by ERIC
A simple viewshed analysis using ArcGIS or equivalent would put this debate to rest. You'd need the x,y,z of where the photo was taken, and USGS elevation datasets (DEM) for the specific peaks in question. The only limiting factors would be standard dataset error (7.5-minute DEM's are 15-meter or better, which is acceptable for analysis at this scale), obstruction from air particulates, and any vegetation or man made objects in the immediate foreground and line of sight.

If you give me the x,y coordinates, I'll see if I can find the time to put something together.

Re: Amazing picture of Half Dome?

Posted: Wed Mar 11, 2009 1:19 pm
by STRETCHMAN
I did not think it was possible,now I believe! ](*,)

Re: Half Dome from Denair CA

Posted: Wed Mar 11, 2009 2:27 pm
by Steve_C
Quoting Eric:
> A simple viewshed analysis using ArcGIS or equivalent would put this debate to rest.

Not sure there is a debate, Eric. There may be doubters, but all they need to do is look more closely at the maps

> If you give me the x,y coordinates,
...of the camera location? Use this in Google Maps: 37.5447 -120.73726

> I'll see if I can find the time to put something together.
It takes more time than you might expect. :smirk:

Re: Half Dome from Denair CA

Posted: Wed Mar 11, 2009 2:46 pm
by ERIC
Steve_C wrote:It takes more time than you might expect. :smirk:
Nah. Easy with ArcGIS. I've made hundreds of viewshed maps over the years. :)

Re: Amazing picture of Half Dome?

Posted: Wed Mar 11, 2009 2:55 pm
by Steve_C
Hikin Mike wrote:Honestly I didn't believe it either, but I kept seeing the location from different people and cameras....so I had to try and find the place. I'm going to see if I can see it from Atwater. I tried this evening but I couldn't find any landmarks.
Mike, to find the camera location, take Shaffer Road north to Oakdale Road. Left on Oakdale, about 10 miles, you will come to the grain elevator in the picture -- it is on the left of the road (which is named Montpelier Road at that point). A half mile north gets you to Keys Road. Go Left to Hall Road, then left again (south). Drive about .6 miles south on Hall Road.

It would probably be 30 minutes from Atwater -- 18 miles. Take your best zoom camera. ;)

Re: Half Dome from Denair CA

Posted: Wed Mar 11, 2009 2:57 pm
by Steve_C
ERIC wrote:Nah. Easy with ArcGIS. I've made hundreds of viewshed maps over the years. :)
Sounds great. Can you post an image of the output?

Re: Amazing picture of Half Dome?

Posted: Wed Mar 11, 2009 3:14 pm
by Hikin Mike
Steve_C wrote:
Hikin Mike wrote:Honestly I didn't believe it either, but I kept seeing the location from different people and cameras....so I had to try and find the place. I'm going to see if I can see it from Atwater. I tried this evening but I couldn't find any landmarks.
Mike, to find the camera location, take Shaffer Road north to Oakdale Road. Left on Oakdale, about 10 miles, you will come to the grain elevator in the picture -- it is on the left of the road (which is named Montpelier Road at that point). A half mile north gets you to Keys Road. Go Left to Hall Road, then left again (south). Drive about .6 miles south on Hall Road.

It would probably be 30 minutes from Atwater -- 18 miles. Take your best zoom camera. ;)
Steve, I know where the "camera" location is, I went there yesterday (twice) and I posted my own picture there yesterday. :D

What I haven't seen yet was Yosemite Valley/Half Dome etc from MY location....Atwater.

Re: Half Dome from Denair CA

Posted: Wed Mar 11, 2009 3:41 pm
by ERIC
Steve_C wrote:Sounds great. Can you post an image of the output?
Sure.
I need to download a couple DEM swatches I don't currently have and then mosaic them to the others before running the analysis.

Attached is similar to what I'm going to try and produce for that location. The observation point is my boss' house in Madera. You're tax dollars at work, folks. :p

EDIT: I just saw the 3D model posted to the SummitPost thread. I was additionally going to do something similar using 3D Analyst, but guess it's not necessary now. I'll save my energy. :smirk:

Re: Amazing picture of Half Dome?

Posted: Wed Mar 11, 2009 4:12 pm
by Steve_C
Hikin Mike wrote:Steve, I know where the "camera" location is, I went there yesterday (twice) and I posted my own picture there yesterday. :D
Oh yeah. Duh. :retard: Sorry.

> What I haven't seen yet was Yosemite Valley/Half Dome etc from MY location....Atwater.
I would be surprised if you could see Half Dome. It has a very narrow view to the west. But you can probably see the highest peaks in the picture.

I agree. That's why I was having a heard time seeing it from Atwater. Still, I have plenty of free time so I'll be on the look out! :nod:

Re: Amazing picture of Half Dome?

Posted: Wed Mar 11, 2009 7:01 pm
by Allyn
ERIC wrote:A simple viewshed analysis using ArcGIS or equivalent would put this debate to rest. You'd need the x,y,z of where the photo was taken, and USGS elevation datasets (DEM) for the specific peaks in question. The only limiting factors would be standard dataset error (7.5-minute DEM's are 15-meter or better, which is acceptable for analysis at this scale), obstruction from air particulates, and any vegetation or man made objects in the immediate foreground and line of sight.

If you give me the x,y coordinates, I'll see if I can find the time to put something together.
Using a very crude version, I plotted out the view, distance and mountains along the way in AutoCAD and in fact you would be able to see a significant portion of Half Dome from where the photo was taken. I used Topo to find the distance and then found the mountains along the way that might block the view and in fact saw that there was a good angle.

But I still think that Hikin Mike photoshopped his picture too! :wink: