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7 votes
Accepted

Averaging shapefiles using QGIS

Use Join attributes by location and set the corresponding layers for 2009 and 2017 as input. The other settings depend on the data you have. Since you have layers from the same source that match ...
Babel's user avatar
  • 71.5k
7 votes
Accepted

Creating composite RGB images from Sentinel 1 channels

First of all, the RGB combination to achieve something similar to the map you showed is: red=VV green=VH blue=VV/VH if you work with linear data. If you work with log-scaled data (in dB) it is ...
AndyB's user avatar
  • 802
7 votes

Calculating water occurrence of Sentinel-1 images in Google Earth Engine

After some research and help, I finally have the solution to the described problem, which I also want to share with the community. https://code.earthengine.google.com/8b39abcdf63cd569ee09a6ac2eb68c93?...
Stephan Büttig's user avatar
6 votes
Accepted

InSAR processing: why can't we just compute distances directly from time delays?

I thoroughly edited the answer to give a more complete picture. The edited answer also reflects what I discussed in the comments. ====================================================== There is not ...
Michael's user avatar
  • 1,186
6 votes
Accepted

Radar Vegetation Index Using Google Earth Engine

You have issues with the collection you're working on because your RVI formula is not correct. By using the 'system:index' of following image in your error message: ...
xunilk's user avatar
  • 30k
5 votes
Accepted

Problem with Sentinel 1 images in Google Earth Engine

The issue is that some of the S1 images in your collection are completely masked after clipping to the geometry of your study area. To fix, filter out those images after creating your original image ...
Nick's user avatar
  • 1,613
5 votes
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SAR processing using Python

ESA's SNAP software does have a Python API which you can set up by following these instructions. Additionally, in your SNAP bin directory you'll find the Graph Processing Tool executable. This ...
Ali's user avatar
  • 4,055
4 votes
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Layers misaligned in QGIS

There seems to be something wrong with the axis orientation of the SAR file. If you run gdalinfo on it, you get: Corner Coordinates: Upper Left ( -84.0569550, 39.8130372) ( 84d 3'25.04"W, 39d48'46....
AndreJ's user avatar
  • 76.7k
3 votes
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Sun-synchronus orbit for SAR satellite

While I don't actually design / choose orbits for SAR satellites, my understanding is as follows. Fundamentally, it is a question of meeting a set of mission parameters. Parameters such as global ...
Mikkel Lydholm Rasmussen's user avatar
3 votes

Using coordinates to access GeoTIFF dataset

Note that your Sentinel-1 data isn't geocoded or orthorectified, so your data shouldn't have any geographical information. You could use higher-level libraries to manage this, like EOReader or xarray-...
remi.braun's user avatar
2 votes
Accepted

How to calculate an incidence angle raster for a radarsat 2 scene using gdal / python?

If you are working in range-Doppler (not projected), you can exploit the information contained in the calibration gains. RS-2 products are generated using an "Application LUT", which aims to correct ...
Benjamin's user avatar
  • 911
2 votes
Accepted

Error in orthorectification of Radarsat-2 scenes with GDAL and RPC + DEM information

With RS2 you need to point GDAL to either the parent directory or the product.xml file. From your code, you are pointing to the *.tiff file directly. So your modified code should be: gdalwarp -...
not_a_NaN's user avatar
2 votes

SAR spectral signatures for oil spill detection from different sensors

A critical point to keep in mind when looking at oil spills on water is wind speed. Oil has the effect of damping the amplitude of waves. Back in the day, when I used to process SAR imagery for both ...
Alexander Taylor's user avatar
2 votes
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Mosaicking multiple Sentinel-1 images in SNAP software

I would like to draw your attention to Mosaicing tool in Raster | Geometrical Operations menu. (*1) Start Mosaicing tool. There are several tabs (as below) in the dialog window; [I/O Parameters] Read ...
Kazuhito's user avatar
  • 30.9k
2 votes
Accepted

Calibration annotation data for Sentinel-1 images downloaded from Sentinel Hub?

If you want to get sigma-naught, you can use backscatter coefficient parameter (see https://docs.sentinel-hub.com/api/latest/#/API/data/Sentinel-1-GRD) or configure the Sentinel Hub layer accordingly:
Grega M.'s user avatar
  • 774
2 votes

What do horizontal (H) and vertical (V) polarization mean for satellite radar?

I think you have the gist of it. From Iain H. Woodhouse's text "Introduction to Microwave Remote Sensing" (a great resource on SAR and RADAR): For convenience, in remote sensing the horizontal axis,...
Charlie Parr's user avatar
  • 1,956
2 votes
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Manipulating Sentinel-1 SAR Imagery to get Pixel Information

If you only concerned with one scene, you can convert the image into geotif using SNAP and then you can use either GDAL or rasterio functionalities. If your concern is on large number of scenes, you ...
Getachew's user avatar
2 votes

Sentinel-1a real azimuth resolution

The formula that gives the azimuth resolution as being equal to half the antenna length is only true in Stripmap mode, where the satellite scans the ground as fast as it moves along its orbit. The ...
guampi's user avatar
  • 271
2 votes

What is the difference between InSAR and PolSAR?

PolSAR and InSAR are two fundamentally different parameters. PolSAR looks at different polarities within one observation, so whether the signal is 'vertical' / V, or 'horizontal' H, when the signal ...
Mikkel Lydholm Rasmussen's user avatar
1 vote
Accepted

Reprojecting raster changes pixel scale (makes it darker)

So the issue was with how QGIS was displaying the range of the raster. As stated in this answer, QGIS, by default does not calculate the range of the entire dataset but estimates it instead. This can ...
ashnair1's user avatar
  • 379
1 vote
Accepted

Steps to view SAR imagery (SICD) in QGIS

While not a perfect solution, the Raster Calculator functionality in QGIS can be helpful here. Typical SICD's are stored as in-phase and quadrature (I & Q) representations of complex values (...
user193695's user avatar
1 vote

Sentinel-1 image backward

Problem solved: it does not happen in the previous version 6 of the SNAP software. I was using the latest version 7. Fixed by uninstalling new software and installing a the older version.
Lizzie's user avatar
  • 21
1 vote

Using intensity of VV, VH, or combination of these for Sentinel-1 GRD

Normally, to reproduce the RGB image, you'd use different values for the different RGB bands: Red: VV Green: VH Blue: VH - VV There's a video worth watching on the subject by the ESA:
kevinxbrown's user avatar
1 vote
Accepted

Using intensity of VV, VH, or combination of these for Sentinel-1 GRD

The two intensities are indeed related to the polarization (V for vertical, H for horizontal; first letter for emission, second letter fo reception)I recommand you to use both and their ratio (not ...
radouxju's user avatar
  • 49.7k
1 vote

Complex SAR values in Interferogram

It's not completely different, but not entirely correct: Say you have two SLC's, each with an amplitude and a phase. When you cross-multiply SLC1 and SLC2*, the amplitude of the resulting ...
DetectionAndRanging's user avatar
1 vote

How can I filter my image collection based on incidence angle in SAR?

You can mask every image based on the angle band like this: var maskedAngles = collectionVV_desc .map(function (image) { var angle = image.select('angle') return image.updateMask( ...
Daniel Wiell's user avatar
  • 14.2k
1 vote

Using GDAL for reading calibration and annotation data set

I Think I found the answer to my question. GDAL says : Currently the (SAR) driver does not apply calibration information.
Sinooshka's user avatar
  • 391
1 vote

Google Earth Engine - Blend Sentinel-1 SAR Images?

Those strips look like the different overpass lines. In short, there were slightly different ground conditions on each of the three "before" days shown in your data which caused the sensor to record ...
ycartwhelen's user avatar
  • 2,402
1 vote

SAR processing using Python

You could use high level libraries such as EOReader to pre-process directly your data (with SNAP under the hood): from eoreader.reader import Reader from eoreader.bands import VV # Open the Sentinel-...
remi.braun's user avatar
1 vote

Using gdallocationinfo on a rotated SAR image to get pixel value at coordinates

Okay, I found the cause of the problem. I got the order of the geotransformation parameters wrong. the georeferencing transform takes the following form : adfGeoTransform[0] /* top left x */ ...
Yardood's user avatar
  • 21

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