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Re: Remote Sensing C

Posted: May 4th, 2011, 4:28 pm
by zyzzyva980
I'd be happy to put it up. The problem might be with the underscores in your username, I've heard that those can cause problems.

Re: Remote Sensing C

Posted: May 4th, 2011, 9:10 pm
by tad_k_22
PM me your email address, I'll send it to you.

Re: Remote Sensing C

Posted: May 6th, 2011, 9:33 am
by haverstall
The first question on emissivity's wording mkes little sense. What does it mean by "total energy by an object"? Is there supposed to be an "emitted" after "energy"?
Also, is this the formula? http://en.wikipedia.org/wiki/Sakuma%E2% ... i_equation
The second question makes sense.

Although, these questions don't seem to be that relevant to Remote Sensing. Ideally, the questions are about satellite imagery, satellites, cameras, types of photographs, analysis of those pictures, etc. but these questions seem to be more related to black bodies...
Well based on previous posts, it looks like the nats test will most likely have a lot of info about satellites.

I guess you have a point that this stuff isn't really related to remote sensing; it does connect in that it's about light and wavelengths.

I don't really know much about emissivity, except the equations. I should probably care more. The Sakuma-Hattori equation doesn't look exactly like the one I posted, but if it gets you the same result :D.

Re: Remote Sensing C

Posted: May 8th, 2011, 6:03 pm
by The Eviscerator
Does anybody know how to calculate spatial resolution based on the band width and/or pixel size?
Also, what are the units for spatial, spectral, radiometric, and temporal resolution?

Re: Remote Sensing C

Posted: May 8th, 2011, 7:28 pm
by haverstall
Could you give an example? I don't think I've ever come across a question like that.

I found some info on wikipedia about calculating spatial resolution, but it was through trig, and using wavelength, and the diameter of the lens' aperture.

Re: Remote Sensing C

Posted: May 8th, 2011, 7:36 pm
by The Eviscerator
Could you give an example? I don't think I've ever come across a question like that.

I found some info on wikipedia about calculating spatial resolution, but it was through trig, and using wavelength, and the diameter of the lens' aperture.
I'll post the question after I see my state test (I don't remember it now). This should be in a couple days (Wednesday?).
Also, what are the units for spatial, spectral, radiometric, and temporal resolution?

Re: Remote Sensing C

Posted: May 8th, 2011, 8:05 pm
by bwy
Also, what are the units for spatial, spectral, radiometric, and temporal resolution?
Spatial- units of length, like m or in. Or it could be square meters, I guess
Spectral- basically how many different wavelengths it can detect (multi-spectral has higher spectral res)
Radiometric- units of intensity, measured in bits usually because it's a computer recording the light intensity, like 256 bits
Temporal- time, like s or days (it's how often the satellite can sample the radiation)

Re: Remote Sensing C

Posted: May 11th, 2011, 8:12 pm
by haverstall
Eviscerator, have you gotten your test back yet? Also, I thought you couldn't get states tests back?

Re: Remote Sensing C

Posted: May 11th, 2011, 8:54 pm
by The Eviscerator
Eviscerator, have you gotten your test back yet? Also, I thought you couldn't get states tests back?
Right, thanks for reminding me. I just got the test back today actually. In NC, the state director lets the teams that are going to nationals look at the state tests.

Here is the afore-promised question (as you can see, my memory of the question was a bit flawed):
If a satellite-based pushbroom sensor has a row of 9,000 CCD cells aligned perpendicular to the satellite's motion, and the swath width is 270 kilometers, what is the ground sampling distance (spatial resolution) in meters?
And I just realized how to do this question *facepalm* so I'll explain it if anyone needs me too.

Okay, here is a hard one: If the satellite in the previous question (the one above) is in a polar, sun-synchronous orbit at an altitude of 705 kilometers, how many minutes and/or seconds of its orbital ground track would be covered by a square image area covering 270km x 270km?
If anyone can explain this that would be great, since I have no idea how to do it. I'll post what the answer is after you guys try to figure it out.

The other questions we got wrong were stupid mistakes... Really stupid mistakes... *facedesk over and over again*

Re: Remote Sensing C

Posted: May 11th, 2011, 9:23 pm
by haverstall
Awesome. I never come across these types of questions before.

I don't really know about the first one, but I think I can make an educated guess about the second one.

A polar sun-synchronous orbit is 100 minutes long (AQUA is an example) and the circumference of the Earth is 6378 km (info from wikipedia). Now some simple division: 270/6378 should give the percentage of the Earth's circumference that the 270km square covers, and multiply by 100 minutes get you...4.23 minutes, or approx 254 seconds.

Don't explain question 1 just yet; I want to do some studying on my own to see if I can figure it out.

Btw, how did you do in Remote Sensing at your state competition?

EDIT 1: So, I'm pretty much coming up blank with the first question. Is it just 270km/9000? Meaning the answer is 30 meters?