Questions tagged [satellite]

In the context of spaceflight, it is an object which has been placed into orbit by humans.

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GDAL - NetCDF to colorized raster

I have a NetCDF file that is satellite imagery. I would like to convert it to a raster image, with color, using gdal on the command line. Here is what I have so far: gdal_translate -unscale NETCDF:&...
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Can we do soil analysis for Nitrogen using remote sensing without field data for validation? [closed]

Background: Remote sensing is used for monitoring land cover change and for monitoring vegetation etc. In addition to that, it is used for soil analysis (alterations in soil properties) as well. There ...
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Display preview of image in semi-automatic classification plugin in QGIS does not load in layers

I have being trying to load Landsat or Sentinel-2 satellite images into the map layers panel within QGIS v26.3 with the latest version of the semi-automatic classification plugin. The screen just ...
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How to automatically extract satellite images from a list of coordinates

I have a dataframe composed of 4000 lines of geographic coordinates of various types of infrastructures. I mainly work on Python. From each of theses coordinates I would like to automatically extract ...
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Detection of permanent changes in low resolution images

I want to detect permanent changes in lows resolution sentinel-2 satellite images, such as new buildings. Most research I found focuses on pair-wise change detection, which leads to many false alarms ...
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How to remove two pixels from the edge of masked raster

I have a raster file, which has empty/masked areas on the edges and then all data inside is not masked. Basically, a sub-swath of satellite data interpolated to rectangle. All is fine, except that ...
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1 answer
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How does a receiver locate with more than 4 satellites?

If it takes 4 equations to find x,y,z and t, how does one improve the accuracy by adding 5th equation or does it reuse any 3 previous equations and recalculate with the 5th equation?
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Image Strips are not showing properly when loaded to ArcGIS. They become Dark

I was working on Narrow Angle Camera (NAC) images of Moon obtained during LRO mission of NASA. I had georeferenced the images but when they are moved to another computer they all become dark means ...
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Is there a list of formats that GDAL supports range download?

I know that the format Cloud Optmized Geotiff (COG) GDAL driver is able to range download a given image using /vsicurl/. I see that GDAL shows in its documentation. I would like to know if there is a ...
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How calc FOV for satellite

I figured out satellite orbital from tle. How I can find fov of satellite sensor in proper time? I have formula, but in output I want x,y coords on map. May be polygon of x,y. • FOV = 2 H tan (scan ...
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Calculate nearest point in a orbital path to user (GPS)

TLDR: how do I go about determining the nearest point in an orbital path to a user's location? Longer version: This is gonna remain a bit vague, I'm uncertain of the terminology needed to ask/answer ...
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Linear data imputation conversion to bilinear interpolation in Python?

I have a project where the task is to impute missing data values from a modis TIF file using Bilinear interpolation. I tried to use linear interpolation to impute the missing values, but trying to ...
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Why does no one use MODIS data from 2000?

While MODIS Terra was launched in 1999 and has data covering the year 2000, no one seems to use this in their analysis but rather starts the data collection from MODIS by the year 2001. Why is that? ...
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Sentinel 2 satellite images API

I want to download or reach Sentinel 2 images as png, jpg. I used Copernicus Open Access Hub but it is not so clear, can someone explain how to download one satellite images with ROI and time?
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Convert Luojia1-01 DN values to radiance

I am trying to convert Luojia's DN values to radiance following the equation in the attached image. I am using the Raster Calculator in ArcMap for this conversion and the command I am typing is image^...
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Can I obtain NDVI mean value for specific point but multiple sites at the same time?

I'm trying to get multiple site at the same time from LANDSAT 8. The next error appears when I run it. ImageCollection (Error) Error in map(ID=20210906): Image.reduceRegions: The default WGS84 ...
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Incidence angle meta-data for Sentinel 1 GRD on AWS

I have seen how incidence angles can be obtained for Sentinel 1 sigma-0 backscatter when processing from the SLC product with SNAP. However, I want to use the pre-processed GRD product. I couldn't ...
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Unique product name for Sentinel-2 products, which does not change after re-processing by the distributor

Currently, I use the names of the Sentinel-2 space imagery product archives as a unique image identifier in the database. It turns out that this identifier contains processing data and time, which ...
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1 vote
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GPM monthly data is inconsistent with the half hourly data aggregated to monthly

I wrote a code in GEE to first aggregate half-hourly GPM data into cumulative daily precipitation and then aggregate daily data into cumulative monthly data. In the next step, to ensure that my code ...
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1 answer
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Downloading recent GRACE data

I have been doing GRACE data processing in GEE, but from what I can tell - only the first mission's data (dating from 2002/04 to 2017/01) is accessible through the library for import. Can I access ...
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EarthPy plot scatterplot on top of plot_rgb

I am using earthpy.plot_rgb() for some satellite image because it works very well. However, I have the coordinates of a line that I'd like to plot on top of it with scatterplot, but I can't make it ...
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Python Rasterio Writes JP2 without Colors

When opening a JP2 image in rasterio, the image seems to have the width and height dimensions flipped. So, I correct by changing the transform and Affine manually: src = rasterio.open("img.JP2&...
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Getting the real pixel size from scan and track

I'm using FIRMS's Fire data, and in the datasheet, they note two values per reading: Scan and Track. They say that those two values reflect the actual pixel size. How to use them to obtain the "...
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Seeking QGIS Tile / Basemap Options

We have been using QGIS to collect and produce maps for fiber optic deployment to areas where there is no fiber. We use OpenStreetMap as the base tile map, for streets and building structures. We ...
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2 votes
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How can we know that a random satellite image is atmospherically corrected or not using python?

If a satellite image in .tiff format was given. what are the values that can be obtained from a satellite image using python to see whether it has atmospheric errors or not? I am expecting what values ...
3 votes
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Projection best practices for applying ML to large scale Earth Observation imagery [closed]

I come from a data science background, rather than GIS, but work in a domain where remote-sensed imagery is widely used; so I'm still learning some of the do's & don'ts when it comes to the 'right'...
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MODIS MCD18A2 (PAR) reproject via rasterio vs. via HDF-EOS

I downloaded MODIS L3 PAR data (https://lpdaac.usgs.gov/documents/750/MCD18_User_Guide_V61.pdf, https://e4ftl01.cr.usgs.gov//DP128/MOTA/MCD18A2.061/2014.07.04/MCD18A2.A2014185.h18v04.061.2021258072101....
1 vote
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What transformation of raw sensor values from Sentinel-2 is GEE using?

What transformation of raw values obtained from Sentinel-2's sensors is Google Earth Engine using? When accessing the data from the Sentinel Hub directly, the values that I get are a bit different ...
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1 vote
1 answer
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Brush up satellite image coloring

I have received the following satellite image. Unfortunately, the color grading is really poor and makes working with this image very tedious (see screenshot below). I am rather new to QGIS. How can ...
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How feasible is it to scan CORONA satellite imagery in the National Archives?

I'm building a dataset of several hundred historical CORONA satellite images for a research project. I know that one can request these images from the US Geological Survey, but new scans cost $30 ...
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GRASS GIS i.sentinel.mask Error

I am trying to run i.sentinel.mask in GRASS GIS 7.8.5 I am having the following Error: ERROR: Option <input_file> is mutually exclusive with all of <blue>, <green>, <red>, <...
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Seeking FREE satellite images than ones provided by MapBox [closed]

I have made a desktop map system for myself with NW.js, MapBox GL JS and MapBox.com's free satellite pictures. I don't have money to pay anyone. While it's cool and fun to use, it's largely ruined by ...
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Satellite sun-synchronous orbits and local acquisition time

I have two questions about sun-synchronous satellite orbits. Firstly, I know that equator crossing time for a particular platform is approximately 10:30 – 11:00 local time (descending node). My study ...
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5 votes
1 answer
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Noisy lines in all scenes for Landsat 7?

I'm seeing patterned lines in all Landsat 7 images that clearly are image artifacts. There are lines that jet in from the edges (the center looks better) Does anyone know what it is and if there are ...
1 vote
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Image Plane or Object Plane Scanning Satellite Instruments

Scanning systems can be classified as either Image Plane or Object Plane, depending on where the light rays converge, as shown in the following figure. I would like to know if the Terra MODIS, ...
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Are Landsat satellites exactly sun-synchronous?

Sun-synchronous satellites are known to pass over any given point of the planet's surface at the same local mean solar time (link-to-wiki). Landsat is one of these sun-synchronous satellites. I'm ...
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3 votes
1 answer
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Why are there no Sentinel-2 images in northern latitudes from November to January?

I have found that there are no Sentinel-2 images in northern latitudes from November through January (near 64.11837149, 67.75836280 coordinates). Number of scenes around the point with coordinates 64....
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Latitude, longitude, elevation and altitude of satellites on a specific GPS receiver

I am currently working on calculating the GPS receiver's latitude and longitude coordinates by using three satellites above the earth. I have used the website https://www.n2yo.com/ to get information ...
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Improve ALOS World 3D vertical precision with GPS data from fieldwork

I'm working on sport topo maps in Russia, european part (Pskov region, near Estonia/Latvia border), typical map is from 1 to 10 km2 in size. The most precise source of DEM for generating relief lines ...
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Shouldn't albedo be determined by surface reflectance?

I am new to this field. I'd like to look up albedo in a small area (about 1 sq km), but I don't know much about how to do it. I was hoping to use surface reflectance with landsat correction, but it ...
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Sentinel-2 L2A metadata XML

I am trying to select Sentinel-2 L2A scenes that have low cloud cover. How should I interpret the difference between these three types of cloudy pixel % values captured here? I made this image based ...
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Understanding resolution of multispectral satellite imagery (EuroSAT)

I am trying to understand the data that is provided in EuroSAT : Land Use and Land Cover Classification with Sentinel-2. It is comprised of "Sentinel-2 satellite images covering 13 spectral bands ...
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I couldn't find Landsat 5 scene starting from 2002-08-04 to 2008-06-01

I am searching for Landsat 5 TM image from 2000 to 2012 in Earth Explorer Web site (https://earthexplorer.usgs.gov/). However, I couldn't find any scene in my study area starting from 2002-08-04 to ...
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1 answer
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How to align set of satellite images?

I have a problem my set of four satellite images (4 different years of observations) of the same area are not aligned and more than that I see that there is a distortion problem also. I found this ...
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1 vote
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Reconstructing satellite sensor swath polygon (multiple orbits, antimeridian crossing)

I'm currently working on a project that involves displaying a given satellite's sensor coverage of Earth, with one of the objective being to count how many swaths overlap a given point on Earth over a ...
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-1 votes
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Seeking free satellite imagery basemaps to be used in webapps with frequent updates

I am looking for satellite imagery base maps to be used in my web application. I have been using Google satellite base maps, but they are very old. I need something which has frequent updates, weekly ...
2 votes
0 answers
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Why does rasterio compression reduces image size with single band but not with multiple bands

I downloaded Sentinel-2 data. This data have 13 files one for each band as jp2 format. I am reading this images the writing them as GeoTIFF format on python using rasterio. These images are large so I ...
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1 answer
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Sat data spatial resolution, where does the XY refer to in the grid?

I have downloaded some NetCDF data. Using R I can obtain the following information for the dimensions > bio_nc$dim$latitude$vals [1] 48.00 48.25 48.50 48.75 49.00 49.25 49.50 49.75 50.00 50.25 50....
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1 vote
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Normalising raster comprised of lots of areas with different MinMax values using QGIS

I've got a raster which is provided to the company I work for on a monthly basis. However, the raster has lots of little areas which have different MinMax values, which give it a pretty bad look, as ...
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Seeking open access 10-30 m spatial resolution imagery?

The data from Landsat-8 and Sentinel-2A&B satellite missions is available at no cost. I am curious to know if there are other sources of freely available multi-spectral moderate resolution ...
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