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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37 views

How can I compute confusion matrix using Python

My project is about "Extracting water and urban features from satellite images". I have extracted urban and water features using Python code. Now, I want to do accuracy assessment. I know two primary ...
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18 views

What are the bands available in MODIS aerosol product? [closed]

I just downloaded a hdf file as MODIS aerosol product (MOD04), after extracting I got 46 files. What are these files?While browsing aerosol product they refer two bands basically?
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1answer
26 views

Do I need to perform any corrections on Level-2 Landsat imagery?

My objective is to perform a land cover classification with multiple scenes over historical imagery (one year every decade). Most of the imagery I have downloaded is level-2 imagery. From my ...
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40 views

Understanding Digital Globe imagery? [closed]

How can we programmatically find GeoTiffs that correspond to same geographical area in pre event and post event capture in Digital Globe or is there meta information available about the images which ...
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10 views

Registration of a panchromatic satellite image to a multispectral image

I have a multispectral satellite image (RGB and NIR band) which will serve as the reference image. I also have several panchromatic (PAN) satellite images which I need to register to the multispectral ...
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1answer
35 views

How to increase or decrease the spatial resolution of a band in Google Earth Engine?

In LANDSAT var mndwi = ee.Image("LANDSAT/LC08/C01/T1_RT_TOA/LC08_148044_20130425").normalizedDifference(['B3', 'B6']).rename('MNDWI') gives us MNDWI Band In Sentinel 2 the resolutions of Green ...
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1answer
53 views

Computing MNDWI for Sentinel 2 Images in Google Earth Engine?

MNDWI is the normalized difference of Green Band and SWIR Band. In LANDSAT both are of a similar resolution i.e. 30m. In the case of LANDSAT var landsat8 = ee.Image("LANDSAT/LC08/C01/T1_RT_TOA/...
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20 views

ALOS PALSAR resampling

I want to combine Landsat bands with the backscatter coefficients of ALOS PALSAR. I used the following code to resample and combine. However, the HH, HV bands in combine image showed with 'masked'. I ...
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1answer
46 views

Sentinel-2 range of values, Level 1C (2A)

Is it correct that images (TIFF 8-bit, B2, B3, B4 bands, sentinel-2 L2A, high resolution) downloaded from sentinel-hub have very poor range of values? Min value is about 30 and max value is about 60 ...
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2answers
33 views

Earth Engine casting bands

I am trying to calculate mean reflectance values across landsat 5 and 8 images using the following code: var point = /* color: #d63000 */ee.Geometry.Point([-133.49, 69.18]); var l5 = ee....
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2answers
27 views

Feature space selection for river sand classification using multispectral imagery

I want to perform supervised classification for river sand detection. I have 3 m spatial resolution Surface Reflectance multispectral imagery with B, G, R and NIR bands (Planet data). Which all ...
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22 views

sen2cor BOA output

I have installed all of the necessary programs for this process (Anaconda, Step SNAP, Sen2cor, etc). I have installed the plugin for sen2cor in SNAP. When I run the Level1-c product through Sen2cor, ...
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1answer
45 views

How do I add multiple indices as bands to an image?

I want to be able to classify my image using bands for prediction (B2, B3, B4, etc.) but I also want to use indices as "bands" (B2, B3, B4, NDVI, EBBI, MSAVI2, etc.). Unfortunately, I can't seem to ...
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0answers
32 views

Smoothing MODIS LAI? [closed]

I am trying to smooth 8 days LAI data from MODIS and managed to work around it with several algorithms such as loess, Savitzky–Golay, smooth.spline etc. This is pretty much going well if the level of ...
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77 views

Determining extra seed for SNIC segmentation algorithm

Here is a part of a program that do segmentation based on SNIC algorithm and indeed compute some statistics based on the resulted clusters to determine the worst outlier for each clusters in order to ...
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1answer
18 views

Does per-pixel viewing zenith angle (VZA) is identical between landsat sensors for a common path/row?

Due to the distance from the nadir viewing vector of the satellite, variation in viewing zenith angle (VZA) is observed from the center to the outer edges of the scene (as shown in figure one). ...
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59 views

Aster L1T: Radiance -product to surface reflectance

Earth Engine provides access to Aster level 1 Precision Terrain Corrected Registered At-Sensor Radiance -product (Aster L1T). I would be interested to reach the surface reflectance values of the image ...
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21 views

How do I remove the black background of ASTER in Envi Classic 5.3 “display window”?

I want to change color or remove black bacground of my aster imagery when "save image as" from display window (that loaded as RGB to display.. is there a quick way to do it? here is the what i ask in ...
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47 views

Getting error running GRASS GIS 7.6.1

Here is the error notice I receive after starting GRASS GIS 7.6. I am not sure what is the source of these errors. I had reinstalled the application but it didn't fixed these errors. What are ...
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25 views

Algorithm(s) for Sensor Footprint at limbs

Is anyone aware of algorithm(s) that have been developed for computing remotely sensed image footprints that handle body limbs? The limb is the edge of the body / atmosphere where only the blackness ...
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1answer
24 views

How to modify MODIS subset function to download product for a specific region and time period?

I am trying to assess the land cover change that has occurred over East Asia over last 18 years only in winters (Oct-Jan) for which I want to use MOD13Q1 dataset of modis from 2000-2018. I am using ...
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21 views

Filter Date From FeatureCollection

I want to filter my crop data table on the basis of dates. I uploaded my file in the assets and call it. Now I am unable to filter this data accordingly datewise. The date column is added in the file ...
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1answer
34 views

Moisture Stress Index - how important is seasonal influence in a deciduous forest?

I want to calculate moisture stress index for a deciduous forest using the formula from the article 'Detecting vegetation leaf water content using reflectance in the optical domain' (Ceccato et al. ...
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27 views

Ground Control Point Experience

I have a number of aerial images that do not align with where my GPS says I am. For example, I am standing at the intersection of two roads with a Trimble R10 and a handheld IOS device with the ...
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1answer
47 views

Downloading Sentinel 2 imagery using Semi-Automatic Classification Plugin?

I have been following this video (https://www.youtube.com/watch?v=FcETq8OWM0k) to download Sentinel 2 imagery using the Semi-Automatic Classification Plugin in QGIS 3. However, when I click run and ...
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23 views

Statistic validation for spectral trajectories/trend from ground truth dataset

I'm doing an extraction of spectral trajectories for disturbed forest pixels using multitemporal (single scene for 20 years) Landsat Surface Reflectance products. Usually, forest disturbances are ...
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0answers
32 views

Calculating MODIS 8-day composite GPP product as yearly [closed]

I want to use MODIS GPP 8-day composite product for an annual time series analysis. How to calculate the annual GPP from the 8-day composite? Since the fractions represent the daily average rates of ...
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1answer
39 views

Computing the harmonic mean of an image collection in the Google Earth Engine

How can I compute the harmonic instead of arithmetic mean for a series of images in Google Earth Engine? There is a build-in function to compute the arithmetic mean and median, but there is no ...
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1answer
53 views

Extracting atmosphere opacity using Google Earth Engine?

I met some doubts when I try to extract Landsat surface reflection product's atmosphere opacity. the code is : var inCollection7 = ee.ImageCollection("LANDSAT/LE07/C01/T1_SR").filter(ee.Filter....
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2answers
50 views

Hansen Global Forest Change - Forest Loss Year - Dates Clarification

I have scoured both the GFC website, research papers and Stack Exchange, but haven't been able to find a clear and reliable explanation of what the "Year of gross forest cover loss event" pixel values ...
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29 views

Clip a Mask (NDSI) from another Mask (NDWI) in GEE

I have created a mask of Normalized difference Snow Index (NDSI) in the late winter using a combination of Landsat 5,7,8 imagery and I would like to only keep a remaining land features by clipping out ...
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2answers
156 views

Landsat 8 - Reflectance Values

I downloaded some Landsat 8 OLI/TIRS C1 Level-1 images from EarthExplorer. I was hoping to get reflectance data out of the blue, green and red band; however, when I opened those images in ArcMap, the ...
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2answers
1k views

Why is short-wave infrared portion of electromagnetic spectrum so sensitive to fire?

After attending a remote sensing workshop and using Copernicus data to monitor natural disaster scenarios, my question could not be fully answered by the instructor. All that was said, was that is in ...
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1answer
36 views

Make Level-2 Landsat images comparable with Level-2A Sentinel-2 images

Is there a way to make Level-2 Landsat images (e.g. Landsat-5 images ordered from EarthExplorer) comparable with Level-2A Sentinel-2 images? The objective is to calculate water or vegetation indices (...
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1answer
175 views

How big is a MODIS 250m pixel in reality?

How big is a MODIS 250m pixel in reality? This appears to be a question that contains its own answer, but I have several reasons to doubt that the pixel size is actually 250m x 250m: I downloaded ...
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1answer
60 views

Landsat 8 Level 2 products. Converting Pan & Thermal bands to spectral reflectance

We have downloaded around 20 Landsat Level 2 Surface Reflectance scenes for our AoI. The processed bands available in the downloaded scenes are, as you people know - Aerosol,B,G,R,NIR,SWIR,Cirrus. ...
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34 views

What is the 4th band in a 16 Bit 4 Band RGB TIFF? [closed]

I am using TIFF files in a project, all of which are plain RGB imagery. When imported into the software program that I use they are just automatically shown as being three bands, Red Green and Blue. ...
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31 views

Labeled training data for water extraction/classification

I'm working on a small project to extract water features from satellite images. In particular, I plan to use Landsat 7 ETM+ satellite images of a particular lake (it's on plain land). I have decided ...
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3answers
86 views

Bare Soil Detection

I try to find bare soil areas. Those which are bare over the whole year and those which are fresh harvest and remain bare over a certain time. I try to do this with sentinel-2 data. But the Problem is ...
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10 views

Normalizing a single band of landsat 8 imagery w.r.t an adjacent one

We have 23 landsat 8 level 2 imageries which has to be mosaiced. Based on date, we have mosaiced individual bands (B1, B2, B3, B4, B5, B6) and now it's down to 5 imageries. But we are not getting a ...
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1answer
91 views

A reproducible example for the use of separability measures in improving selection of spectral variables

I have been working with the tutorials in GEE on supervised and unsupervised classification, but I haven't come across any examples on the use of separability measures such as Jeffreys-Matusita, ...
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2answers
103 views

Removing noise from point cloud with lidR package

I have unclassified Terrestrial Laser Scanning (TLS) point cloud data which has some noise. Is there a function in the lidR package which can be used to remove noise?
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1answer
61 views

Sentinal NDVI Time series Chart and CLassification

I am working on NDVI time series analysis using Sentinal data and also classifying the data it will give some error and not working and how can i get the chart of three different features in ...
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0answers
19 views

Doing atmospheric correction of LISS-IV standard data product?

I have purchased RS-2 LISS-IV Standard Processing Level data. The product type is Geo RPC. Metadata is in IKONOS format. I want to compute surface reflectance from original DN values. What is the ...
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38 views

Radiometric correction of Aster Level 1T

We have to mosaic 70+ ASTER Level 1T imageries. I've splitted hdf data into 14 different tif's (3 VNIR, 6 SWIR, 5 TIR). As shown in the image imageries are of different time period. Question is, is ...
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1answer
29 views

NDVI Analysis of a small area from the year 2000- 2011 [closed]

I want to perform an NDVI analysis in a small area. I want to see the change around a river body for the year 2002, 2005, 2008, 2010 and 2011. I tried using Landsat-7 data but due to the scanline ...
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2answers
89 views

Feature normalization (scaling) for Hyperspectral images

I have been straggling with the concept of feature normalization for the hyperspectral images. Respect to my problem I have attached a picture of my problem which clearly stands the issue which I have....
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1answer
27 views

Finding sericite alteration in ENVI 5.3 spectral library?

I work on an area where there is a sericite alteration and i searched for the sericet and did not find a word. I want to know what is called sericet in the spectral library of ENVI 5.3? Sericite is ...
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0answers
42 views

What does Google Earth Engine's image.unmix() differentiate from other implementations?

I want to realize a project with spectrally unmixed Landsat imagery. However, I find no satisfying information on the respective GEE function, image.unmix(). I processed a few scenes with the exact ...
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47 views

Apparent disappearance of NLCD 1992/2001 retrofit land cover change product

I am attempting to download the national land cover datasets 1992-2001 retrofit land cover change product from the mrlc site. The product exists throughout documentation and I have not found any thing ...