Earth Science Stack Exchange
Earth Science Stack Exchange

Questions tagged [remote-sensing]

Questions about measurements which are taken from remote locations / are not taken in situ.

Prominent remote sensing methods use electromagnetic and acoustic waves to measure properties at a distant location.

108 questions
14
votes
2 answers

What color is the Sahara desert, as seen from orbit?

In images of the Earth taken from spacecraft (or composite images thereof), the color rendering seems to be really inconsistent. Examples (Source: NASA,…
John
  • 865
  • 5
  • 10
14
votes
1 answer

GOES Visible Channel - asymmetry between morning and afternoon

In the GOES-13 Visible channel, there seems to be a morning/afternoon asymmetry in the data. I'm wondering what might cause this. In this example data, the morning is the lower branch, and the afternoon is the upper branch. The y-axis is the pixel…
John
  • 865
  • 5
  • 10
11
votes
1 answer

Are the elements of an averaging kernel matrix always centered on the diagonal, or can they be exclusively off-diagonal in rare cases?

According to Rodgers (2000) equation 2.80 $$ d_s = \mathrm{tr}(\mathbf{A}) $$ where $d_s$ is the number of degrees of freedom for the signal, tr denotes the trace, and $A$ is the averaging kernel matrix. I'm trying to properly understand this. For…
gerrit
  • 11,704
  • 2
  • 37
  • 87
5
votes
1 answer

Should Modis & LandSAT NDVI composites agree and why not?

Modis takes daily images at coarse resolution (500m?) that are then lumped into 16-day composites. LandSAT, let's say 8, takes roughly bi-weekly images at 30m (100m resampled to 30), and those are then lumped into 32-day composites. Clouds aside,…
J Kelly
  • 273
  • 1
  • 4
4
votes
2 answers

What are the differences between down-looking and side looking radar?

In Radar concept the SAR-Synthetic Aperture radar performs as side-looking to collect information, why it is not downlooking? There are down-looking radar also. So what are the differences between them
Gokul Anand
  • 153
  • 4
3
votes
0 answers

Planetary Reflectance vs Relative Spectral Response

I am confused between a Planetary Reflectance and the Relative Spectral Response (RSR). What I know/guess is that RSR is a response/function of an Instrument band's reflectance against a spectral range. Isn't that reflectance the Planetary…
Nikko
  • 141
  • 2
3
votes
0 answers

Pansharpening of Spot 6 image

Would the pansharpening of Spot 6 work on the NIR band? Since the wavelengths captured by the panchromatic band does not overlap with the NIR band. The band designations are in the attached image.
Chayan Lahiri
  • 395
  • 1
  • 8
2
votes
1 answer

Landsat 8 acquisition time and date

The the meta data text file that comes with Landsat scenes, contains an acquisition date and a scene center time in successive lines. I wanted to know if the image is recorded at the scene center time on the date of aquisition.
Chayan Lahiri
  • 395
  • 1
  • 8
2
votes
1 answer

Using NASA's radiance calculator to make a graph to find the where the peak radiation emission are?

I am trying to graphically show the radiance emissions of both the Sun and Earth. I am using NASA's radiance calculator then going to graph it on paper. Here is what I typed in: Low wavelength: 0.1μm high wavelength: 100.0μm Plot 1: Temp: 5778k <-…
yre
  • 485
  • 1
  • 4
  • 11
1
vote
0 answers

How we convert TOM

TEMIS NO2 tropospheric Data by KMNI Netherland is retrieved in TOMIS (ASCII) format. My issue is to convert the said format in to ESRI Gird format or any other Raster format to analyze the retrieved data file in ArcGIS format. Thanks
Arjan Das
  • 11
  • 1
1
vote
0 answers

Remote sensing and GIS

Please how can I get landcover landuse data from landsat 4 or landsat 5. Please can anyone help me and provide me the details?
Ramson kabenla
  • 11
  • 1
1
vote
0 answers

DEM coordinates do not align other data layers

I recently downloaded Original Product Resolution (OPR) Digital Elevation Model (DEM) data for some analysis. The DEM do not align with any of the other data sets I have for the area. How can I rectify this problem?
Chayan Lahiri
  • 395
  • 1
  • 8
1
vote
0 answers

NDWI from Landsat 8

I have layer stacked Landsat 8 image, how can I calculate Normalized difference water index (NDWI) from it? I would have been able to calculate it easily using the raster calculator, if I had the green and NIR bands individually.
Chayan Lahiri
  • 395
  • 1
  • 8
1
vote
0 answers

Google earth historical imagery date

I am working on a small creek in Colorado using historical imagery via Google earth. I want to know if the imagery date at the bottom of each image on google earth is the date the google acquired the image. Or, is it the date the satellite recorded…
Chayan Lahiri
  • 395
  • 1
  • 8
1
vote
1 answer

What is the most real-time method of determining SPI?

For drought monitoring related to vegetation, I need to calculate Standardized Percipitation INdex for a given area. Where can I find the most real-time percipitation data to do this? The best I've found is CHIRPS data, which has a latency of one…
Maarten
  • 11
  • 1
1
2