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Questions tagged [sar]

Synthetic-aperture radar (SAR) is a form of radar

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Supervised classification ALOS-PALSAR Google Earth Engine

I need to create a supervised classification for flood detection with ALOS PALSAR in Google Earth Engine. How can I do this?
Paula Torres's user avatar
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How to retrieve Sentinel-1 data with specifying orbit direction (ascending or descending) using OpenEO

I am using Python's API for OpenEO. This is the code I have for the datacube: sentinel1_cube = con.load_collection( "SENTINEL1_GRD", spatial_extent={"west": 21.60, "south"...
Akhmad SW's user avatar
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1 answer
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Using band epoch to obtain date time stamp of data from a specific location

I would like to use JAXA/ALOS/PALSAR/YEARLY/SAR_EPOCH' V2 for HH HV backscatter values and have tried to use epoch band to display date of observation using: var obsdate = data.select('epoch') I was ...
gymo5FLG's user avatar
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Winter spikes in SAR GRD magnitude in Middle East

I've been looking at SAR images (GRD) of the Middle East using Google Earth Engine. I notice that in the winter time there is often spikes in the VV and VH measurements. Looking at the images ...
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Calculating NDFI for every week of the year

I wish to calculate the Normalized Difference Flood Index of every week in a year for a region using Sentinel-1 imagery in GEE. The NDFI equation is, I am confused about how to set the reference ...
Raihan's user avatar
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Sentinel-1 SAR Level 1 Data

From where I can find the satellite Metadata ( satellite position vector, velocity) for the corresponding SAR Level 1 image? I have tried to look but didn't find the source to download these files.
M D's user avatar
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In the official Sentinel 1 GRD product in SAFE format, where is the view/incidence angle?

As the title says, I am trying to figure out where in the metadata is the information on view angle stored. I can see it has information on min and max view angle, but I want a raster with the angle ...
Jose's user avatar
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1 vote
1 answer
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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 ...
Sakib Rahman Siddique Shuvo's user avatar
1 vote
1 answer
323 views

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 ...
wesleysc352's user avatar
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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 ...
Yuka Sashihara's user avatar
1 vote
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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 ...
Tony Almeida's user avatar
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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 ...
Tony Almeida's user avatar
1 vote
1 answer
206 views

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 ...
nicholaskr23's user avatar
2 votes
1 answer
238 views

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=...
Sina's user avatar
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342 views

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 ...
chiyi y's user avatar
1 vote
1 answer
82 views

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 ...
Opegraphy's user avatar
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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 (...
Kachra Dabba's user avatar
2 votes
1 answer
3k views

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 (...
Reflex_180's user avatar
1 vote
0 answers
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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 ...
Marlon Calispa's user avatar
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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?
Tirthankar Ghosh's user avatar
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117 views

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....
Nidhi Verma's user avatar
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129 views

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, ...
Na_Na_Na's user avatar
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1 vote
2 answers
647 views

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 ...
xanthi's user avatar
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1 vote
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103 views

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 ...
Nidhi Verma's user avatar
1 vote
0 answers
661 views

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 ...
vicemagui's user avatar
2 votes
1 answer
756 views

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",...
vicemagui's user avatar
1 vote
0 answers
48 views

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 ...
Celine's user avatar
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1 vote
1 answer
202 views

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, ...
Supriya Bhide's user avatar
4 votes
1 answer
271 views

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 ...
Stephanie Liefmann's user avatar
1 vote
0 answers
215 views

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 ...
Michael A.'s user avatar
4 votes
1 answer
4k views

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 ...
TCR's user avatar
  • 117
2 votes
1 answer
515 views

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 ...
ashnair1's user avatar
  • 379
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1 answer
573 views

What is the difference between InSAR and PolSAR? [closed]

How to define those two SAR Technologies?
ctrlcreep's user avatar
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1 answer
1k views

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 ...
mjldbr's user avatar
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1 answer
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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 ...
susanee_28's user avatar
2 votes
1 answer
758 views

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 ...
Gokul Anand's user avatar
3 votes
2 answers
241 views

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 ...
1milenac's user avatar
1 vote
1 answer
131 views

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 ...
Lizzie's user avatar
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0 votes
2 answers
3k views

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 ...
Petró Bálint's user avatar
3 votes
1 answer
73 views

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 ...
Lenn's user avatar
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1 vote
0 answers
496 views

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 ...
Siddeshwar Raghavan's user avatar
1 vote
1 answer
464 views

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 ...
elissavet_geo's user avatar
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1 answer
81 views

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 ...
elissavet_geo's user avatar
0 votes
1 answer
264 views

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, ...
underchemist's user avatar
3 votes
2 answers
3k views

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 ...
Stephan Büttig's user avatar
8 votes
1 answer
501 views

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. ...
jc711's user avatar
  • 83
2 votes
2 answers
534 views

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 ...
David B's user avatar
  • 53
1 vote
0 answers
210 views

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 ...
Slav's user avatar
  • 151
4 votes
1 answer
296 views

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....
Slav's user avatar
  • 151
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1 answer
172 views

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 ...
Sinooshka's user avatar
  • 391