Re: [Talk-us] Sevier Lake Anomaly
You're both right :) Check it out Toby: http://www2.jpl.nasa.gov/srtm/instr.htm On Thu, Feb 17, 2011 at 9:27 AM, Toby Murray wrote: > On Thu, Feb 17, 2011 at 7:57 AM, Phil! Gold wrote: > > The OpenCycleMap elevation data comes from the SRTM dataset, which was > > obtained by taking stereoscopic images from the Space Shuttle. > > I thought the R stood for Radar, not steReoscopic? But yes, SRTM data > is known for being flaky. > > Toby > > ___ > Talk-us mailing list > Talk-us@openstreetmap.org > http://lists.openstreetmap.org/listinfo/talk-us > ___ Talk-us mailing list Talk-us@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-us
Re: [Talk-us] Sevier Lake Anomaly
On Thu, Feb 17, 2011 at 7:57 AM, Phil! Gold wrote: > The OpenCycleMap elevation data comes from the SRTM dataset, which was > obtained by taking stereoscopic images from the Space Shuttle. I thought the R stood for Radar, not steReoscopic? But yes, SRTM data is known for being flaky. Toby ___ Talk-us mailing list Talk-us@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-us
Re: [Talk-us] Sevier Lake Anomaly
* Val Kartchner [2011-02-16 20:13 -0700]: > What I'm asking about is this anomaly in the area of Sevier Lake: > "http://www.openstreetmap.org/?lat=39.0035&lon=-113.0895&zoom=14&layers=C";. > What is up with this sudden change in terrain? The OpenCycleMap elevation data comes from the SRTM dataset, which was obtained by taking stereoscopic images from the Space Shuttle. There are all sorts of things that interfered with the data capture in individual locations, from highly-reflective things (like snow-covered mountain peaks) preventing their elevation from being determined, to the fact that the elevation data is treetop- or buildingtop-level, not ground level, to inexplicably large holes in the data (see http://flic.kr/p/82QGk7 ). My guess would be that this region's data was recorded in two passes and there was a dust storm or something that looked to the shuttle like a hill. Note that TopOSM, which uses the USGS National Elevation Dataset, doesn't show anything there (probably because NED is clipped to the surface of bodies of water): http://toposm.com/us/?lat=39.0035&lon=-113.0895&zoom=12&layers=B0TT (TopOSM also shows a lot of intermittent streams from the USGS National Hydrography Dataset.) -- ...computer contrarian of the first order... / http://aperiodic.net/phil/ PGP: 026A27F2 print: D200 5BDB FC4B B24A 9248 9F7A 4322 2D22 026A 27F2 --- -- You step in the stream, but the water has moved on. This page is not here. --- -- ___ Talk-us mailing list Talk-us@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-us
Re: [Talk-us] Sevier Lake Anomaly
On 2/16/2011 10:13 PM, Val Kartchner wrote: What I'm asking about is this anomaly in the area of Sevier Lake: "http://www.openstreetmap.org/?lat=39.0035&lon=-113.0895&zoom=14&layers=C";. What is up with this sudden change in terrain? Most likely the quality or method of creation of the data in this area changes at the 39th parallel. ___ Talk-us mailing list Talk-us@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk-us
[Talk-us] Sevier Lake Anomaly
What I'm asking about is this anomaly in the area of Sevier Lake:
"http://www.openstreetmap.org/?lat=39.0035&lon=-113.0895&zoom=14&layers=C";.
What is up with this sudden change in terrain?
I found it because I was going to trace Sevier Lake as a lake.
("http://en.wikipedia.org/wiki/Sevier_Lake";) After a while I decided
that since its levels varies so much, I would leave it to a local
mapper. I did leave what I had traced so far, just not as a lake.
There is an abandoned proposal to trace intermittent lakes.
("http://wiki.openstreetmap.org/wiki/Proposed_features/Intermittent_Lake";)
Should this be revived?
- Val -
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