Questions tagged [remote-sensing]

Collecting and interpreting information about the environment and the surface of the earth from a distance, primarily by sensing radiation that is naturally emitted or reflected by the earth's surface or from the atmosphere, or by sensing signals transmitted from a device and reflected back to it.

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1answer
22 views

Google Earth Engine: memory error when calculating monthly average precipitation for a small region using GLDAS data

I am trying to calculate the total monthly precipitation rate using the Rainf_f_tavg band of the GLDAS-2.1 image collection on Google Earth Engine (https://developers.google.com/earth-engine/datasets/...
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1answer
14 views

Tried to Mosaic Sentinel 2 images but my final image appeared with some overlapping Null data

I'm working on an area that required me to use three sentinel images to fully cover it, I used the "mosaic to new raster" tool in ArcGIS to merge the three images and was surprised to find ...
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22 views

Spectral Indices: Division by zero?

I am trying to calculate spectral indices from Sentinel-2 reflectance values, the range of which I normalized to be in [0; 1]. I realize that in quite a lot of the products I downloaded, for many ...
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35 views

Training Deep Learning models in Colab (Python) by exploring Google Earth Engine dataset (independant variables) [closed]

I want to train some Machine learning models (Neural Nets) under Tensorflow where the predictor variables are [NPP, LAI, NRI and other vegetation indexes] imported from GEE platform and the dependant ...
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1answer
68 views

How to loop through each feature in a shapefile in Google Earth Engine?

I have written a script which calculates the mean NDVI, NDWI, and NDDI (Normalized Difference Drought Index) values for a given county in a specified time period. These values are then outputted to a ...
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1answer
17 views

Google Earth Engine - error in function to plot seasonal vegetation index for a region using MODIS data

I am trying to create a function to calculate the average Vegetation Condition Index ((mean NDVI of individual year)-(min NDVI from full period)) / ((max NDVI from full period) - (min NDVI from full ...
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18 views

Finding the angle between two GIS linestring features using R

I have two simulated linestrings, one that represents a satellite ground-track and the other representing a linear surface feature (e.g., sea ice lead, road or river). I'm trying to determine how to ...
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25 views

Cannot download Landsat 8 images from RGISTools R package

I've been having a hard time trying to automate some Landsat 8 image download and processing for my project. At first, I tried to use getSpatialData package to do what I need from R, but it seems the ...
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1answer
38 views

Remote sensing product's raster extent not agreeing with specified projection in R

I want to plot remote sensed sea ice concentration data for Antarctica, in Program R. The product website (http://cersat.ifremer.fr/data/products/catalogue) says the data are in Antarctic polar ...
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28 views

GEE NDVI time series extraction does not populate CSV file columns

I am trying to extract a time series of sentinel NDVI data. This script (below) takes a feature collection of points, buffers around them, and collects all available imagery 30 days before each ...
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1answer
36 views

What is name of dataset in GEE to estimate level of urbanization for each county (district) in a country /region?

I am epidemiologist, not remote sensing expert. I am interested to find association between disease incidence /reported cases with urbanization (hypothesis " more bigger cities , more incidence&...
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31 views

Google Earth Engine goes unresponsive during large extraction

What we are trying to do: We are trying to extract a NDVI time series for a large dataset of insect outbreaks. This time series needs to be associated with the observation date for each insect ...
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1answer
35 views

Exporting EVI image on Google Earth Engine with visual parameters between -1 and 1?

I am having an issue with exporting an EVI image with the visual parameters between -1 and 1. On Google Earth Engine (GEE), using the inspector tool, the values are between -1 and 1, but when I export ...
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44 views

Putting a point over pixels with highest DN values within grids in QGIS [duplicate]

I have a raster layer in greyscale, and a vector layer that is 3 x 3 m grid. One of the attributes within the grid cell layer is the value of the highest DN number within that grid cell. I just need ...
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30 views

How to mosaic two satellite images from two diffrent orbits?

I have to satellite images on two diffrent orbits. My research area lies between these images. I would like to perform classification as well as an analysis of the condition of vegetation.I would ...
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28 views

Crop a satellite image to 32 by 32 pixel

I have a satellite image of resolution size 10 m. I want to get a cropped image of 32x32 pixels of that image using a polygon. I randomly generate a polygon no matter the size but to reduce the ...
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15 views

Color-correcting/matching 4-band PlanetScope imagery

I've been trying to color correct/match 4-band (R, G, B, NIR), 3m resolution Planetscope surface reflectance imagery in order to create a mosaic for land-cover classification. At this point, I believe ...
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1answer
104 views

Applying Otsu thresholding method to raster in QGIS

How can I apply Otsu’s threshold method to a Raster in QGIS for reduction of a gray level image to a binary image?
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1answer
36 views

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

How to define those two SAR Technologies?
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19 views

Using Photo Monitoring plugin in a macro in Fiji (ImageJ)

I am trying to run a macro that will automatically open my 8 band geotiff, stack it has an RGB(false color with Red, Green and NIR) and at the end use the Photo monitoring plugin to create the NDVI. I ...
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2answers
162 views

Computing Excess Green Vegetation Index (ExG) in QGIS [duplicate]

I have to process the image for Sugarcane row detection and extraction. Sample image is accessible from the link: https://github.com/AndresHerrera/croprows_generator_pa_v2/tree/master/droneimages I ...
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22 views

Spatial filtering technique for Image enhancement

In Spatial filtering, the output image has fewer rows and columns than the input image because it has an unfiltered margin corresponding to the top and bottom rows and the left and right columns of ...
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1answer
43 views

Designing a Low Pass Filter

How can I design a similar Low Pass Filter as given below which takes into account only 4-connectivity and ignores the pixels that complete 8-connectivity?
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2answers
86 views

Is Satellite Image Continuous Data?

I have a satellite image of one region. I perform interpolation on this image. However, I am not sure Satellite Image is continuous or discrete data.
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8 views

Need to change the histogram values in ERDAS Imagin 2014

Can I change values in a histogram column in the attribute table of continuous or thematic raster image in ERDAS Imagine 2014? If yes, please explain where and how!
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1answer
42 views

Problem dry fields- urban areas on supervised classification in QGIS, Landsat 7

I am trying to make a supervised classification on a Landsat 7 image using the QGIS 3.16.1 version. I am using the SCP plugin to do then classification. I am doing the classification using the RGB ...
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15 views

Spectral signatures difference between a raw image and an atmospherically corrected image

I did atmospheric correction of Landsat 5 image by Quick atmospheric correction method(QUAC), now I want to compare atmospheric corrected spectral signatures from ENVI QUAC with the input spectral ...
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1answer
62 views

Radiance and Raw Image difference after Radiometric calibration

I have done Radiometric calibration on Envi 5.3 and got the output of my input Landsat 5 image. What is the difference between the raw image and the radiance image and why is this value of radiance ...
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65 views

Difference between two atmospherically corrected Images

I corrected Landsat 5 image with two different methods, first atmospheric correction through calibration (means converting raw image into radiance), second atmospheric correction through QUAC ...
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23 views

GEE slope: Tile error: Reprojection output too large (29005x28882 pixels)

I am trying to do linear regression between sentinel-1 SAR backscatter and NASA SMAP soil mositure, here are a couple of doubts i have regarding my code SAR nominal resolution is 10m and SMAP is ...
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21 views

Finding optimal number of clusters for wekaKmeans unsupervised classification in the Google Earth Engine

I want to find the optimal number of clusters for wekaKmeans unsupervised classification in the Google Earth Engine. The reason is that I want to see which cluster division is the best. Here is my ...
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31 views

Calculate PV rooftop potentials in Berlin QGIS 3.16. (OS Windows 10)

I want to analyse PV potentials of roofing in QGIS (v. 3.16). I am experienced in vector data analysis but have barely worked with raster data sets. I therefore have no experience and am asking for ...
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1answer
16 views

Reasons for partial tiles in Sentinel

In many cases, when we download a Sentinel tile, it contains only a portion of the full tile. This information is contained as a metadata in the NODATA_PIXEL_PERCENTAGE. But why these tiles are ...
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6 views

Confusion about “alpha” band for MODIS Aqua

I'm working with modis:09:CREFL data for a harmful algal blooms paper, and I am trying to figure out how to call the chlorophyll-a band, which I believe is the "alpha" band, but I'm not sure ...
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54 views

How to rotate orthographic projection using basemap

I'm working with the python basemap library and am plotting data over Greenland using an orthographic projection. However I find that due to the location of the coordinates, basemap auto plots the ...
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1answer
20 views

Sensing data Sentinel-3 time zone

I have a question about sensing data time zone from https://scihub.copernicus.eu/dhus/#/home. In which time zone copernicus provide for us data ? For example on image we can see Sensing Date Is it CET ...
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37 views

How to convert large size hyperspectral from tif to lan

I tried to convert hyperspectral from .tif to .lan format. There are three file with size about 1.5GB , 750MB and 200MB respectively. I use this code from osgeo import gdal src_fname = 'file.tif' ...
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1answer
78 views

Correcting Worldview-3 data to ground reflection/bottom of atmosphere with open source?

I have some worldview-3 imagery that needs to be corrected from digital numbers to actual reflection values (preferably bottom-of-atmosphere). But the tricky part is I am looking for open source ...
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1answer
71 views

Optimal Sentinel 2 Bands combination for NDMI

I want to calculate NDMI (Normalized Difference Moisture Index) using Sentinel 2 bands on QGIS. I am not sure if right formula is B8-B11 or B8A - B11. Band 8 seems to give better results but on the ...
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1answer
54 views

Time Series Extraction of Modis LAI product (every 3 days a new satellite image) in small study area

At the moment I am struggling with a time series and the extraction of MODIS LAI data. I am using the band "Lai" from MODIS/006/MCD15A3H. My study area is small, so presumably, since the ...
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0answers
29 views

Calculate and plot the feature importance of the input dataset of a random forest classification within Google Earth Engine (GEE)

I run a random forest classification for agricultural land use and other land cover classes (12 classes). My dataset for 2019 consists of a Sentinel 1 and Sentinel 2 monthly time series, statistical ...
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17 views

Sentinel-2 active fire detection service

I'm looking for a Sentinel-2 analogue of the FIRMS service (Fire Information for Resource Management System), which provides the location of active hotspots. The low spatial resolution of MODIS and ...
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1answer
50 views

Fulfilling removed cloud area with free cloud data in Google Earth Engine

I have completed doing cloud removal with Landsat image (in this case is Lansat 8) in the Google Earth Engine. Of course the result of this process is the cloud pixels become no data, consequently the ...
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27 views

SNAP Sen2cor Correction

While applying sen2cor correction in SNAP on sentinel-2 L1c product i receive this error "cannot find L2A data strip directory" how i solve this error
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1answer
32 views

Why are my forest areas orange and non-forest areas green in Google Earth Engine?

I'm doing GEARS' 3rd lab tutorial on Remote Sensing in Google Earth Engine. I calculated the NDVI of an area in Batchellor, Australia. The result is a black and white image so I added a color palette. ...
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2answers
32 views

Data for Sentinel-2 L2A product (suddenly) missing in GEE for certain dates

This code returned imagery for two date ranges previously. It suddenly stopped working for the 2nd date range (2018-06 to 2018-09). I explored setting the cloud cover threshold up to 99 and searching ...
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1answer
46 views

How can the maximum temperature (tmmx) band in the TerraClimate GEE dataset be interpreted?

This question was already asked here. But there was no correct answer. link I'm using the precipitation, maximum temperature (tmmx) and soil moisture in the TerraClimate dataset in GEE. I cannot find ...
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23 views

Identification of cloudy days based on Net Radiation data

How can I identify that a particular day is cloudy or clear sky based on the daily time series of Net Radiation (calculated at FluxNet/AMERIFlux sites)? I read somewhere that clear sky radiation has ...
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33 views

Landsat imagery corrections

I have downloaded Landsat collection 1 Level 1 imagery (Landsat 4,5,7 and 8) from https://earthexplorer.usgs.gov/. I would like to know that do we have to apply some conversions or corrections before ...
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1answer
43 views

Issue while creating dataset mask for Landsat 7 ETM+ band data by using rasterio

I am trying to create dataset mask of a particular band of Landsat-7 (B2) & Landsat-8 (TIR) data and then plot the same using the following code: For Landsat-7 Band-1:- import rasterio import ...

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