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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25 views

What is the appropriate input scale factor for EVI?

I am trying to calculate the Enhanced Vegetation Index using Landsat surface reflectance data. The formula for EVI using standard constants is: EVI = 2.5 * ((NIR – Red) / (NIR + 6 * Red – 7.5 * Blue + ...
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12 views

Terra MODIS MOD09GQ Preprocessing [closed]

What is the pre-processing step needed before using Terra MODIS Level 2G (MOD09GQ)?
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1answer
12 views

Conversion of UAV DN values to reflectance

My aim is to carry out fusion between Sentinel 2 and UAV images. Sentinel images are already converted to reflectance values but UAV images are in DN number format. How can I convert UAV DN values to ...
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14 views

Planet SkySat - Differences between image strips

I'm trying to understand why i'm seeing variations in the analytic (surface reflectance) imagery brightness values in Planet SkySat imagery between image strips that were collected around the same ...
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2answers
63 views

Issue with scaling factors for Landsat Collection 2 Level 2 data when calculating NDVI

I'm trying to calculate the NDVI for a scene, and I've downloaded Landsat 8 OLI/TIRS Collection 2 Level 2 data, which means it has already been processed to surface reflectance. The scaling factors ...
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1answer
48 views

Intake-STAC: KeyError: 'open_stac_item_collection'

I downloaded the AWS Earth search notebook from the intake-stac examples and whithout changing anything. Just run the cells... But I've got everytime the error: KeyError: 'open_stac_item_collection' ...
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11 views

Computation Time Out in Complex Multi-Band Normalization of Sentinel 2 Image Composite

I am trying to implement Pseudo-Invariant Feature Normalization for Sentinel 2 image in 2015 based on the median composite acquired in 2019 (script can be found here). I once ran the script without an ...
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27 views

Process large ROI in GEE

I am calculating the VCI for Europe, but the ROI is too large for a single run in GEE. How can I divide it and process it in chunks so that when downloaded they fit into a single image/composite? var ...
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1answer
35 views

Mapping paddy rice fields with PMI(Paddy rice mapping index) with Google Earth Engine

I would like to perform mapping paddy rice with the Google Earth Engine for large scale. I came across with an article which proposed method for mapping paddy rice with special index related to ...
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0answers
16 views

Extracting shorelines from BW aerial photos using ArcMap

I'm currently trying to analyze rates of shoreline change for an estuarine reserve by extracting & vectorizing shorelines from historic aerial photos, and then comparing those to the modern ...
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21 views

Set axis in Google Earth Engine Chart

I'd like to compare LAI (Leaf Area Index) data from the same region over different times using ui.Chart.image.series in Google Earth Engine. I'm trying to set the axis to the same range, in order to ...
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0answers
45 views

Removing cast shadow from Landsat 8

I've got Collection 2, level 2 Landsat 8 dataset which contain mountains. The problem is the cast shadows from the mountains, so that I can't classify these pixels well. These pixels have much lower ...
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34 views

Smile Random Forest / computation timed out /Computed value is too large

I want to make a binary clasificación (1 = burned area, 0 = non burned area) using smile random forest, to train Sentinel 2 SR (12 band included NDVI and DBR) and get new burned trained areas. I try ...
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1answer
21 views

Filter by bound on Google Earth Engine not covering the whole of bound feature

I tried to filter Sentinel-2 image collection by bound, then I visualized the first in the collection after clipping to the bound feature. The problem is that the returned images does not cover the ...
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35 views

RS & GIS (QGIS Plugin) not producing Land Surface Temperature Layer

Recently I downloaded this plugin as it has demonstrated capability to produce Land Surface Temperature Calculated layer. I tested this plugin using the Landsat 8 contents straight from USGS Earth ...
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4answers
643 views

What is lost when converting 12 bit imagery to 8 bit?

SPOT 6/7 satellite imagery is captured with a dynamic range of 12 bits per pixel per channel (ref). However almost all of the SPOT imagery I have seen in use has been 8 bits per channel, and split ...
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0answers
11 views

How to estimate the land surface temperature using ASTER image in ENVI 5.3?

I am doing research about land surface temperature using ASTER image. I have read literature but i cannot do it in ENVI 5.3. Could you provide step-by-step to calculate land surface temperature using ...
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0answers
40 views

Resampling Sentinel-2 ImageCollection on GEE having the bands with the same spatial resolution

I'm a beginner at Google Earth Engine. I've seen on previous topics that resampling can be made on single images, like in this topic on downscaling raster images. I have an ImageCollection of Sentinel-...
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10 views

Satellite image is cut, when the composite tool is run on it- ArcGIS

Hi I am using satellite imagery in my project. The images come in squares, after using composite to join the bands, one square shrinks or is clipped somehow. Does anyone know the solution? Thanks. ...
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2answers
14 views

How can I have the ground sampling distance from the images?

I have some aerial images and I need to know how if I can have the ground sampling distance value from the image without calculate it from the plane fly's parameters.
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30 views

Predict continuous variable (forest biomass) using trained Tensorflow model

I want to predict forest biomass over my study region. To do that I have trained Tensorflow model using field data (70 Temporary forest plots) and some remote sensing variables that i've extracted ...
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1answer
47 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
25 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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1answer
112 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
39 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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0answers
26 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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37 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
49 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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0answers
31 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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54 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
42 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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0answers
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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31 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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0answers
28 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
180 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
40 views

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

How to define those two SAR Technologies?
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0answers
23 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
277 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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0answers
24 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
49 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
111 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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15 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
46 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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0answers
17 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
82 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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0answers
70 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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0answers
46 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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0answers
33 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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0answers
37 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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