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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6 views

Mask clouds across multiple images using Google Earth Engine

I Have multiple Landsat8 images at the same place in different years. I want to have a cloud mask for each image, then merge the mask so that all images will be masked with a same aggregated mask. I'...
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1answer
45 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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673 views

Pansharpening radiance/reflectance of Landsat 8 in GRASS 7?

first at all, I have to say that I'm new GRASS user. I would like to make a pansharp in GRASS 7 with reflectance Landsat 8 bands. I have revised some related posts and blogs, and I didn't find out if ...
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2k views

Examples of GIS or Remote Sensing in movies

Looking for examples where GIS or RS has been a part of a movie plot. I'm trying to put together a "GIS & RS and the Cinema" class, in which examples of GIS & RS are shown. Those examples will ...
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31 views

Conversion of MLS/AURA RELATIVE HUMIDITY PRODUCT to correctly referenced GeoTIFF

I have downloaded the following product https://cmr.earthdata.nasa.gov/search/concepts/C1251101764-GES_DISC.html and it gives me a .he5file. Can anyone help me in correctly geo-referencing the file ...
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1answer
31 views

Applying Google Earth Engine cloud mask on each individual image BEFORE mosaicing the images?

How can I apply a cloud mask to each individual image in a collection THEN mosaic them together based on (for example) mean pixel value across images? The code does not work because the maskClouds ...
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1answer
27 views

Is re-gridding a good idea?

I am working with MODIS Aerosol data (the Level-2 AOD_550_Dark_Target_Deep_Blue_Combined product). I am retrieving the data using the LAADS DAAC data API, and requesting all swaths as GeoTIFF files. ...
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1answer
29 views

Geolocation of L2G-Lite MODIS data

I would like to know if I am processing an L2G-Lite MODIS product, do I still need to geolocate, or reproject it to EPSG:4326? Or can I just leave it?
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TIMESAT3.3 output errors

When I ran "fit2img" in TIMESAT3.3,I got problematic result image.Contrasted with original image, this result image seemed to be cut into two parts and was badly deformed.I did not know what happened....
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1answer
131 views

Convert Planet Imagery Surface Reflectance product DN to surface reflectance values

I have a PlanetScope Ortho Scene Product (3B) which includes an AnalyticMS.tif and AnalyticMS_SR.tif files. Based on what I have read so far, the AnalyticMS_SR.tif file is scaled surface reflectance ...
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1answer
50 views

Seeking remotely sensed data for measuring urban gardens?

One of the students in my lab is currently seeking methods for measuring the very small size of urban green spaces in people's gardens. Is there a data set out there that may be appropriate for this?...
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44 views

Extracting DEM from PRISM data?

I have PRISM data which is in the following format. Are there any ways (software and methods) to extract the DEM or elevation information from these data files?
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2answers
278 views

Collecting Thermal Map Data?

I am curious about making a thermal map to display where the hot spots and where the cool spots in a community are. Obviously the roads will be hot and the shaded areas with trees will be cool but ...
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1answer
70 views

SAR spectral signatures for oil spill detection from different sensors

I have a rather general question about supervised classification for oil spill detection. I want to apply supervised classification on the ESA SNAP dark spot detection tool results. My question is: if ...
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2answers
49 views

Can BFAST algorithm be applied to to a whole study area/ ROI?

I am working on identification of breakpoints in Landsat based NDVI time series (1990-2018). I am using The Breaks for Additive Seasonal and Trend (BFAST) algorithm which is a pixel based time series ...
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Remove clumps of pixels in R

I would like to remove isolated pixels (or clumps of pixels <9) from my raster image. library(raster) # create some raster data r <- raster(ncols=12, nrows=12) set.seed(0) r[] <- round(runif(...
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Difference between local and global image co-registration

I want to co-register Landsat and Modis image after Reprojection and Resampling. So for that I was trying to understand the difference between local and global image co-registration of this library. ...
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1answer
41 views

Which band to use for LSWI?

I have a sentinel 2 L1C data and I am trying to calculate the Land Surface Water Index (LSWI) using the NIR and SWIR bands. As the Sentinel 2 data is having 2 SWIR bands (B11 and B12), I am confused ...
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815 views

Gram-Schmidt pan-sharpening in QGIS?

I need to perform Gram-Schmidt pan-sharpening, I don't have access to ArcGIS or ENVI so have been using QGIS. Is there any plug-in or similar capability that is available to perform Gram-Schmidt pan-...
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2answers
139 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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2answers
109 views

Do I need to do Radiometric Normalization for time series analysis, if I'm using L2_Landsat8_SR data?

I'm doing some forest change detection across several years using L2_Landsat8 Surface Reflectance data. And I am implementing the method available in R (landsat::relnorm) for relative radiometric ...
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2answers
112 views

Resampling 1000m resolution Aqua MODIS images to 30m resolution

I am trying to resample the MODIS (aqua) image from 1000m resolution to LandSat image resolution which is of 30m for applying ESTARTFM technique. So you need to do preprocessing (Resampling and ...
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22 views

Seeking tool to calculate area specific Tasseled cap coefficients?

It is well established that Tasseled cap coefficients are sensor-specific and are available to disaggregate the amount of soil brightness, vegetation, and moisture content in individual pixels in ...
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1answer
84 views

Unable to download VIIRS images with GIBS API and gdal_translate

I'm trying to download some VIIRS images from GIBS API. I'm using gdal: gdal_translate -projwin 19.07 42.16 28.39 34.5 -of "GTiff" "viirs.xml" "VIIRS_SNPP_DayNightBand_ENCC.tif" The viirs.xml file ...
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2answers
921 views

What is NIR LiDAR?

Can LiDAR sensors collect near-infrared (NIR) data at the same time or does there need to be a separate NIR camera that is combined with the LiDAR data after collection? Blue Marble makes reference ...
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1answer
29 views

Using NDVI along with regular RGB and NIR bands for image classification

Is it plausible to use NDVI along with other regular bands for image classification related data processing? Recently, I came across a comment that RED and NIR band might interfere with NDVI or vice ...
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2answers
40 views

Water reflectance effect on Sentinel 2 images

I'd like to know what is causing the effect on the water depicted on the following screen (sentinel tile id: S2B_MSIL1C_20190805T144739_N0208_R139_T20PPA_20190805T162922 located near Saint Lucia). You ...
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5answers
2k views

Simple way to collect the Sentinel data of a given ROI?

If you wanted to collect all Sentinel satellite data for a given region of interest (ROI), say, for a given day or time frame - is there any simple way to do it? That means: Without having to download ...
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1answer
711 views

Accuracy assessment in Erdas imagine

Is it necessary to do an accuracy assessment for an unsupervised classification done for a Landsat 5 image?
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2answers
1k views

ENVI band math incorrect values

I'm attempting to calculate vegetation indices in ENVI 5.2 using level-2 AVIRIS data in band math. The indices I'm working with are Vogelmann Red Edge 2, normalized difference red edge, and red edge ...
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1answer
432 views

Extract Pixel Values for Multiple Polygons and Images

I have 21 polygons and for each polygon I want to extract the pixel values inside them for Sentinel 1 images from 2017-01-01 to 2017-06-30. The example below shows how this is done for one polygon. ...
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1answer
89 views

Whether Sentinel 3 OLCI can be used as a MODIS replacement for 250m NDVI?

Based on the bandwidths MODIS bands 1 and 2 (620nm - 876nm) will match S3 bands Oa7 - Oa17 (620nm - 865nm) I am just trying to know if anyone had any experience in using S3 data instead of MODIS for ...
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1answer
29 views

Fusing Collection 1 Landsat 7 and 8 Surface Reflectance NDVI

I'm fusing L7 & L8 surface reflectance into an NDVI time-series. I'm using the method described in Roy et al. 2016 to convert L7 NDVI to L8 NDVI using a simple regression equation found in table 3:...
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1answer
114 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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3answers
217 views

Can a satellite go over the same area in different passes overtime

Can a sun-synchronous satellite (let's consider Sentinel-1) go over the same place, one time in an ascending pass and the next time (or few times after) in a descending pass?
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2answers
561 views

Using Quality Control process for MODIS Leaf Area Index?

Anyone can help in explaining how I can apply Quality Control (QC) for MODIS Leaf Area Index (LAI) to extract the valid pixels of LAI using ArcMap?
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1answer
61 views

Dataset description AREA_OR_POINT

What are the differences between these two options in satellite image metadata?
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1answer
283 views

RGB values in Landsat 8 image

When I click on "information" of a Landsat 8 image (bands 1,2,3,4,5,6 and 7 are combined), I get three RGB values: 10928, 10137 and 10265 respectively. What do these values mean? They don't ...
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1answer
6k views

Reprojected MODIS NDVI has range from -32768 to 32767, expected -1 to 1

I'm new to StackExchange and to remote sensing. I am working with MOD13Q1 250m 16-day MVCs. My goal is to use NDVI time-series to classify cropping pattern and crop type, then link this data to ...
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4answers
561 views

Destriping landsat 7 images?

I want to work with landsat 7 images for land cover and NDVI evaluation. There are strips in the landsat images, and I don't know how to remote them. I have learned methods for gapfill but I don't ...
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1answer
390 views

Are landsat 8 SR and TOA rasters calibrated/corrected data or the data to be used for calibration/correction?

I downloaded Landsat 8 Level-2 scenes from https://espa.cr.usgs.gov/ for land cover classification. Following are the product list in the package, cause I ticked Top of Atmosphere Reflectance (TOA), ...
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2answers
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How to define new classes from a change detection raster layer [closed]

As part of my thesis, I'm looking at the atmospheric and landscape effects of the 2018 wildfire in the Algarve. As part of the process, I want to estimate total biomass loss so I have classified two ...
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0answers
56 views

How can I compute confusion matrix using Python [closed]

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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1answer
32 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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1answer
34 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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2answers
2k views

How to analyze Vegetation Index using Sentinel-1 SAR Imagery?

I am using the ESA open scientific data hub for Sentinel 1 SAR imagery (Interferometric Wide swath SLC VV polarization) and would like to know how to perform vegetation health analysis from this data? ...
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21 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
62 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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6answers
11k views

Is GPS more accurate on specific hours of the day?

I have heard that the GPS system is more accurate, and less accurate on some specific hours on the day. If this is true, how can I get the information on when GPS is more or less accurate at my ...
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2answers
17k views

Difference between irradiance and radiance, remote sensing reflectance and water leaving radiance

I've been trying to lay my hands on textbooks, etc, that explain the differences between the remote sensing terms in lay man language. radiance and irradiance remote sensing reflectance and water ...