Questions tagged [sar]
Synthetic-aperture radar (SAR) is a form of radar
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Error when trying to collocating Sentinel 2 and Sentinel 1 Imageries in Google Earth Engine
I am trying to collocate Sentinel 1 and Sentinel 2 images for supervised classification in Google Earth Engine. Synergistic use of optical and SAR images. I am trying this code:
// Load Sentinel-1 and ...
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Practical difference between intensity and amplitude in SLC SAR Sentinel 1 data
In the SLC product, amplitude data is not explicitly provided by SLC Sentinel 1, only the real (i) and imaginary (q) bands of each polarization obtained, in addition to a band called “Intensity” for ...
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How to obtain coordinates of Sentinel-1 image
I’m a beginner in satellite image analysis. I want to know the lat/lon coordinates of some bursts of a sentinel-1 image. I looked at the file names of the downloaded zip, but couldn’t find any ...
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Regression model where N is greater than number of polygons
I'm trying to construct an analysis where 100 users record data for each polygon in the map below, a total of 17 values per user. Using the values from each polygon, I wanted to generate a model that ...
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Antenna pattern/illumination corrections in Google Earth Engine
I am using the analysis ready Level 2.2 ALOS-2 PALSAR-2 data available in Google Earth Engine. Here is an example provided by GEE: https://code.earthengine.google.com/?scriptPath=Examples%3ADatasets%...
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Overlaying Sentinel-1 collection scenes on Google Earth platform
I'm new to GEE and I need to create some code to estimate Soil Surface Moisture (SSM) in Google Engine. However, when generating the image on the map, the product has an issue with overlapping scenes ...
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Apply list to every row of image - raster calculator
I have a SAR image. I have a list of noise levels from the metadata. The list applies in the range direction of the image (across the image - perpendicular to the satellites flight path). The list ...
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How to estimate soil surface moisture using change detection algorithm (TU Wien Change Detection model) in Google Engine?
I would like to use ESA open science data from Sentinel 1 SAR images to estimate soil surface moisture using the change detection algorithm (TU Wien Change Detection model). I found this script on ...
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Applying code to to work with image collection
I found a code for Edge Otsu implementation to detect water body in Sentinel-1 SAR. However, this code only works with one image. I would like to adapt this for the whole image collection. Is there ...
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Using coordinates to access GeoTIFF dataset
I'm trying to read a tile from the Sentinel1 SAR data collection. I'm using rioxarray to open the .tiff data file.
rioxarray.open_rasterio(
path_to_data,
overview_level=...
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QGIS dzetsaka plug-in for satellite image classification error how to do?
When I used dzetsaka plug-in of QGIS to process the SAR image of Gaofen No. 3 satellite, I wanted to use Gaussian mixture model and random forest for classification according to the different ...
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Issues implementing data fusion in EO Browser
I am trying to implement this custom script for flood mapping in EO Browser. I have added the datasets using the additional datasets button, and specified the required timelines, but I keep getting ...
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DEM from Sentinel 1 C-band SAR
I have been using the standard protocol (ESA/ASF) to generate DEMs (actually DSM which is what S1 C-band gives) from Sentinel-1 C-Band SAR tiles. My locations are in the Eastern Himalayan foothills (...
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Radar Vegetation Index Using Google Earth Engine
I tried to calculate Radar Vegetation Index with Google Earth Engine using the code given below. The Value of RVI should range between 0-1. but I'm getting following error
Code:
var RVI= function (...
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Sentinel 1 stripping artifact
I am processing a S1 SLC image as follows: Read>Apply orbit file>S1 TOPS Split>Radiometric Calibration (complex)>S1 TOPS Deburst>Polarimetric Speckle filter>Terrain correction (Range ...
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Band used for deformation estimation using In-SAR
Which polarization of SAR data (C-band - Sentinel-1A) shall I use to get a better deformation map of a mountain terrain - VV or HH?
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Geocoding Moon SAR image using corner latitude and longitude
I have tried geocoding the SAR image of the Moon.
I have the latitude and longitude information for the four corners.
In Python, I am using the GDAL command to geocode.
!gdal_translate -a_ullr -1....
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Magnitude and Amplitude in SAR are different?
Are these two terms, amplitude and magnitude of radar signal, the same? If they are different what are each one?
I have been reading some papers and some authors seem to use them interchangeably, ...
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Calculate water area of SAR images of Google Earth Engine
I use this link to extract surface area of water bodies from SAR images
Google Earth Engine ROI area falling outside/partial coverage by Sentinel 1 Tile
But now I would like to calculate the area of ...
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Terrain correction in SAR image
I am new to the gdal utility. Using DEM data of the Moon, I am trying to perform terrain correction on SAR images. I have a DEM file and SAR data into tif file format. Both DEM and tif file are in ...
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Create GeoTIFF from data array using the original file metadata
I received a .mat file which is the processed data from a Radarsat-2 scene. My goal is to transform this data array into a GeoTIFF file, onto the same projection as the original Radarsat-2 image.
I ...
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The nature of SAR pixel value VS. of panchromatic pixel value
When we compare sentinel-1 SAR orthorectified 8-bit image vs a very high resolution panchromatic 8-bit image, the panchromatic cells are a resemblance of signal amplitude in an 8-bit scale (0-255). ...
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Plotting GeoTIFF using Cartopy
I am trying to plot a SAR image, in TIFF format and containing the following projection arguments, using Cartopy.
PROJCS["WGS 84 / EPSG Norway Polar Stereographic",
GEOGCS["WGS 84",...
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Identifying rectangular structures on SAR image
I'm looking through SAR images and I found this (see SAR image below).
And here's what it looks like on Google Satellite.
As you can see, there's no similarly shaped structure found on the satellite ...
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How does one geocode 2 points with same Lat-Long but different heights?
I am working with Ground-Based SAR (radar) data. My task is to geocode the image. I am new to Geocoding. I was reading through various geocoding approaches that explain how to convert latitude, ...
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Averaging shapefiles using QGIS
I am working with the shapefiles from the OSPAR on fishing intensity. I have the shapefiles from 2009 to 2017 I would like to "merge" them in order to obtain a mean value for all the ...
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SLC IW Visualization in Python/Matplotlib
I'm hoping to add Sentinel 1 data to a tool I'm building. Preferably I would like to use GDAL to load the image, and extract the pixel values from the image. I realize that the pixel values are ...
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Creating composite RGB images from Sentinel 1 channels
I would like to create a RGB image using Sentinel 1 data. It appears the standard way is to assign VV, VH, and VV/VH for the R, G, and B channels. I do, however, have a two questions.
One. It is ...
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Reprojecting raster changes pixel scale (makes it darker)
I have an HH polarised SAR image as follows:
This is how it looks in QGIS in the default EPSG:4326 projection.
Now I would like to reproject this raster to ESRI:102020 (South Pole Lambert Azimuthal ...
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What is the difference between InSAR and PolSAR? [closed]
How to define those two SAR Technologies?
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Steps to view SAR imagery (SICD) in QGIS
I would like to view SAR imagery in a SICD file in QGIS. I am able to load the file and view it as a singleband gray image, but the image does not look correct - features are not detectable and the ...
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Error in visualising MDPI band
I am trying to stack a 3 band image (2 NDVI bands and 1 MDPI band). There is some error when I am trying to visualise the MDPI band (which is appearing as masked in the Inspector) and hence the ...
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Problem with Sentinel 1 images in Google Earth Engine
I am trying to apply Otsu algorthm to S1 images starting from its launch to till date on my study area for waterbody mapping. I perform otsu without applying any date filter for Satellite pass so I ...
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Error occurring when converting to dB during the python-based classification
I am trying to perform an object-based classification using a python-based script with rsgislib. Although, when converting to dB, an error is appearing. Any ideas why is this happening?
Create and ...
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Sentinel-1 image backward
I have this problem with my images of the Ross Ice Shelf:
This is an image that has been Radar - Radiometric- Calibrate- Amplitude_HH - Gamma0
followed by Speckle Filter.
This is what happens when I ...
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Using intensity of VV, VH, or combination of these for Sentinel-1 GRD
I have Sentinel-1 IW GRD images; for each capture date, one GeoTIFF with the VV and one with the VH values. I assume these are intensity values for the co-polarization and cross-polarization bands.
To ...
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Complex SAR values in Interferogram
By what I understand, a "standard" slc from a SAR has complex values for each pixel. Here the phasor consists of the magnitude and the relative phase. What I don't understand is the complex nature of ...
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Changing contrast of GeoTIFF using Python
I have a GeoTIFF image that I can split into the 4 layers. Now I wish to increase the contrast of the layers and stitch them back together. However when I use numpy to do this, I am unable to increase ...
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How can I filter my image collection based on incidence angle in SAR?
Im completely new to SAR, and Im trying to understand the basics.
Im studying a small area in Google Earth Engine, and Im making timeseries of water pixels with SAR imagery. However, I observed ...
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The image collection doesn't correspond to my interactive map (Sentinel-1 in Google Earth Engine)
I want to classify water pixels with Sentinel-1 in Google Earth Engine, and I'm using this code I found here: https://mbonnema.github.io/GoogleEarthEngine/07-SAR-Water-Classification/
However, in my ...
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QGIS view raster with no CRS without on the fly reprojection
I have RADARSAT-2 imagery which is georeferenced with Rational Polynomial Coefficients (RPCs), but is not orthorectified. QGIS will reproject/resample the raster to a defined CRS like EPSG:4326, ...
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Calculating water occurrence of Sentinel-1 images in Google Earth Engine
I would like to derive the occurrence of surface water bodies from Sentinel-1 image collection in the Google Earth Engine.In my example I could already compute the water mask using Otsu’s method for ...
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Layers misaligned in QGIS
I have two National Imagery Transmission Format Standard (NITF) files loaded into QGIS 3.10 and they should be the same coordinate system but for some reason I cannot figure why they are not aligned.
...
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Manipulating Sentinel-1 SAR Imagery to get Pixel Information
For S1 SAR imagery data, how would I go about accessing the data of individual pixels? I need to analyze pixel intensity based on their lat and lon coordinates. I know this information is viewable in ...
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SAR calculating distance between 2 points
I am playing around with ESA's SNAP software and Sentinel-1 data and I was curios if it is possible to measure the ground distance between 2 points in a radar image. For example let's say that I am ...
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Sentinel-1a real azimuth resolution
I was exploring this satellite's payload characteristics on ESA's website and I saw that it's azimuth resolution varies a lot. For example azimuth resolution for IW mode is 22m (https://sentinel.esa....
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Using GDAL for reading calibration and annotation data set
I have a Sentinel-1 .SAFE data which provides a wealth of information through .tiff images and also .xml files containing annotation and calibration information.
Following the instructions in the ...
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Synthetic Aperture Radar data format
I'm trying to learn about the SAR image formation process. From reference such as Carrara's Spotlight Synthetic Aperture Radar book, it appears that after various compensations, a direct 2D fft can ...
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Google Earth Engine - Blend Sentinel-1 SAR Images?
Does anybody know why I am getting these strips across my Sentinel-1 images and how to fix it?
I am using multiple images over Mozambique between January 1st and January 13th.
I want to use this ...
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Histogram matching in Google Earth Engine?
Does anyone know if there is a more GEE-friendly way of achieving this? I'm experimenting with S1 SAR image histogram matching in GEE and was wondering if foremost the code can be improved. Read here ...
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