Questions tagged [reflectance]
Reflectance is the ratio of incident flux and reflected flux from a surface
75
questions
0
votes
0
answers
27
views
Is it necessary to convert Digital Numbers to Radiances to calculate NDVI in GEE with Sentinel 2 and Landsat 8 images?
Translated text:
I am starting to use the Google Earth Engine platform, and I want to calculate the NDVI for Sentinel 2 and Landsat 8 images. I wonder if I have to do some calculation, first, to ...
0
votes
0
answers
29
views
LANDSAT-7 strange strip on SWIR bands (B5 and B7)
I was exploring Landsat 7 data on SentinelHub and came across with this strange strip in the SWIR band B7 (also B5):
By placing a pin in this strip and exploring the stats, I found that there is no ...
1
vote
2
answers
127
views
Google Earth Engine and Sentinel-2 L2A processing update
As of 25-January-2022 ESA has updated its processing baseline for Sentinel-2
Therefore, Sentinel-2 L2A Bottom of Atmosphere (BOA) reflectance (L2A_BOA) should be retrieved using L2A_BOAi = (L2A_DNi + ...
- 1,545
0
votes
0
answers
8
views
MODIS MOD09GA product B6 "stripes"
I'm trying to work with the MODIS surface reflectance data of B6. I'm have downloaded the MOD09GA product, and the image format is HDF.
It seems that all the images present "stripes" on B6. ...
- 3
0
votes
1
answer
24
views
SPOT 6/7 conversion to BOA/Surface Reflectance
I am quite new to GIS and even newer to SPOT as an image source. In general, all of the other sources I have used for analysis (Landsat 7 & 8, Sentinel-2) have been corrected to BOA reflectance ...
- 85
1
vote
0
answers
25
views
Do I need to convert OLI bands DN values to reflectance and TIRS bands DN values to radiance?
I know that this a very trivial question. I downloaded some Landsat 8 images from the USGS website that have the following format (I deleted the processing date):
...
- 41
0
votes
1
answer
181
views
Filter Landsat 5 Surface Reflectance Images by Cloud Cover with a Region of Interest in GEE
I'd like to filter a large collection of Landsat 5 Surface Reflectance images by cloud cover within a small region of interest (not the entire image scene) in Google Earth Engine. I know there are ...
1
vote
0
answers
13
views
Does single tile, single date of Sentinel-2 data require BRDF?
I have a single tile of Sentinel-2 Level-2A data from a single date of acquisition.
Does this require bidirectional reflectance distribution function (BRDF), or are the angles consistent enough during ...
- 233
0
votes
1
answer
210
views
Calculating blue sky albedo with MODIS & Google Earth Engine
I am trying to calculate the blue sky albedo, which I think is the same as land surface albedo, using Google Earth Engine and the 'MCD43A3.006 MODIS Albedo Daily 500m' data.
I've managed to find ...
- 1
0
votes
1
answer
328
views
Cloud masking the Landsat-8 Surface Reflectance product without using GEE
I have a collection of Landsat8 Collection2 Level2 images (surface reflectance) and I would like to cloud mask those images somehow, so I can further make a time series of NDVI and other remote sensor ...
- 1
1
vote
1
answer
102
views
Limiting cloud estimation of Landsat8_SR over ROI in GEE
I intend to create an image collection of Landsat-8 surface reflectance not TOA that has 100% free cloud over my Region of Interest (ROI). Not surprisingly the code I have found in the forum ( Filter ...
- 13
2
votes
1
answer
294
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 ...
- 477
0
votes
1
answer
416
views
Rescaling Landsat-8 SR to surface reflectance
I want to rescale the Landsat-8 SR image using the rescale factor in the documentation, which is 0.0001 for each band. I assume that the original values are DN values, and after rescaling I can get ...
- 317
2
votes
1
answer
96
views
NDVI out of range
I have composed a mosaics of 3 images of Landsat 8 Surface Reflectance Level 2 for the bands NIR and RED. According to the Landsat Surface Reflectance Product Guide each band is supposed to be ...
- 323
2
votes
1
answer
97
views
Explanation on band conversion from radiance to reflectance final value
I've watched few video on conversion of radiance to reflectance for landsat band, most of them recommended to use formula below to to make sure the final reflectance value lies in between 0 to 1. My ...
- 31
1
vote
1
answer
82
views
Understand values for Landsat 8 surface reflectance image
What do the numbers represent when you download an image, in my case Landsat 8 OLI TIRS surface reflectance.
Are they DN numbers or reflectance values?
If the image is not surface reflectance product, ...
- 585
0
votes
1
answer
453
views
How to apply a Bitmask for radiometric saturation QA in a image collection (earth engine)
I am new to earth engine and I am trying to apply a radiometric saturation mask in a image collection based on ''radsat_qa'' in earth engine data catalog for landsat reflectance tier 1.
I am trying ...
- 41
1
vote
1
answer
373
views
PlanetScope NDWI calculations
I am trying to calculate NDWI for a PlanetScope image scene. I currently have 2 products: one is the "3B_AnalyticMS_SR.tif" and the other is the "3B_AnalyticMS.tif" product. I ...
- 19
1
vote
0
answers
99
views
Implementing BRDF in R
I use UAS to survey vegetation at subcentimeter resolution for my research and have found that bidirectional reflectance (BR) is a huge issue that impacts the reliability of estimates across ...
- 2,404
1
vote
0
answers
101
views
Calculation of TOA radiance from Sentinel-2 1C product reflectance
I was trying to convert the Sentinel-2 1C product to radiance and came across two links first once says
radiance = ((pixelValueBandX * cos(incidenceAngle) * solarIrradianceBandX) / (pi * d2)) / ...
- 163
2
votes
0
answers
94
views
Calculating Reflectance from Parrot Sequoia DN
I am dealing with the images of a Parrot Sequoia. I could not pre-process the images in Pix4d because I took single shots in different parts (so there are not overlapping images).. for me it is ...
- 21
0
votes
1
answer
50
views
Comparing Landast 8 Images?
I'm currently working with Landsat 8 OLI/TIRS Level-2 Data Products - Surface Reflectance and I would like to compare different landsat images from different places on earth. I was wondering if pixels ...
- 11
1
vote
2
answers
603
views
Conversion of Landsat ToA reflectance to BoA reflectance with an equation
I am using temporal datasets from Landsat 5, 7 and 8.
Since I have many datasets I would like to include the conversion from ToA(top of atmosphere) to BoA(bottom of atmosphere) reflectance into a ...
- 15
1
vote
1
answer
303
views
Converting Landsat8 DN to TOA reflectance using GEE manually
I'm fairly new in Google Earth Engine and JavaScript. I'm trying to convert Landsat8 DN to TOA reflectance using GEE using a function.
// Load a raw Landsat scene and display it.
var image = ee.Image(...
0
votes
1
answer
42
views
Blank table when exporting a feature selection of a image collection
I'm trying to get reflectance data of some points that i've gotten from another database through a Json table of pings.
I've used this code to get the data but returns only the title of columns with ...
user142308
2
votes
2
answers
1k
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 ...
- 329
4
votes
1
answer
814
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 ...
- 51
0
votes
0
answers
65
views
How to Correct Landsat 8 Imagery with TOA Reflectance >1 and <0?
I recently downloaded Landsat 8 T1 imagery and have ran into some difficulties during pre-processing. I applied the TOA reflectance and sun elevation corrections to Bands 2,3,4,5,6 using ArcGIS's ...
- 1
1
vote
1
answer
1k
views
Converting Digital Number (DN) to reflectance in order to analyze NDVI
I'm working with a mapir nir + red camera meaning that its blue band captures nir light and its red captures red normally. I understand that NDVI is calculated using reflectance values.
How do I ...
- 11
0
votes
1
answer
676
views
Radiometric, reflectance and atmospheric correction for Landsat 8 image
I am struggling with the pre-processing process for landsat8 imagery.
I want to use some indices (e.g. NDVI, SAVI, EVI, NDMI) and create a land cover map at the end using ENVI and ArcGIS.
As a ...
- 55
6
votes
1
answer
2k
views
LiDAR returns over water bodies?
I have obtained LiDAR data from my environmental agency in order to obtain the relative heights of each watercourse station. A far as I know, LiDAR signals do not get returned over water bodies. ...
- 9,965
1
vote
2
answers
138
views
Why reflectance map in pix4d dont are normalized
I want to know, why my reflectance map, dont have value between 0 and 1. Because my calibration table said me: for example red band has max value = 0.88 nm, and my reflectance map in red band have max ...
- 117
0
votes
0
answers
114
views
Set multiple values to nodata - Erdas Imagine 2015
I am having trouble with the data ranges in the Landsat 8 surface reflectance product which I downloaded from USGS. The Lansat 8 surface reflectance handbook says the valid range is 0 - 10,000 range ...
- 1
0
votes
1
answer
187
views
I can apply tasseled Cap transformation in surface reflectance (not ToA)?
I can not understand if I should adjust the Tasseled Cap index with the surface reflectance values or the Top of Atmosphere
2
votes
0
answers
143
views
When to rescale reflectance data to calculate vegetation indices
I'm attempting to calculate a number of vegetation indices using hyperspectral AVIRIS data in ENVI. Some of these indices are normalized, such as NDVI, whereas others are not, such as the Transformed ...
- 395
2
votes
1
answer
252
views
Negative Surface Reflectance
I am using Landsat Surface Reflectance Level-2 images. I have to convert the DNs to reflectance values. When I apply the formula provided in the Landsat8 User Handbook :
reflectance = ...
- 123
3
votes
1
answer
443
views
Landsat8 surface reflectance rescaling pixel
Sorry for this basic question, but I am using Landsat8 images with "surface reflectance" treatment from Landsat8.
I am having some trouble with the data from some bands. Most of pixel are beyond 10k.
...
0
votes
1
answer
100
views
Obtain reflectance map in pix4d?
I can not obtain my reflectance map in pix4D.
The program said:
Unable to computed radiometric calibraticon from sequoia. Unable to
computed coordinated system.
Its rare, because normally i ...
- 117
2
votes
1
answer
5k
views
How to get property of each image in a collection in google earth engine?
I am trying to convert ASTER image from DN values to reflectance. For this I require gain coefficient of each image in the collection I have gathered.
//Defining geometry
var geometry = ee.Geometry....
- 21
2
votes
1
answer
676
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), ...
- 315
0
votes
1
answer
728
views
What are the necessary correction/calibration on Landsat 8 imagery for land cover classification? [duplicate]
I downloaded calibrated/corrected Landsat 8 data (Level 2) from ESPA (https://espa.cr.usgs.gov/) to do land cover classification. But there are many corrections and calibrations can be done as listed ...
- 315
2
votes
1
answer
162
views
Surface reflectance product - do I always need it?
There is a neat Surface Reflectance product of Landsat imagery. I know the difference between SR and raw products: SR presents calculated values, that are supposed to represent state of the Earth ...
- 739
1
vote
1
answer
955
views
Negative values in Landsat 8 surface reflectance higher level product
I have downloaded Landsat 8 higher level surface reflectance product from USGS to genetare chlorophyll map in lake. But the individual bands contain some negative surface reflectance values. So, when ...
- 75
0
votes
0
answers
952
views
Calculate reflectance for UAV images
I have high resolution images captured by a drone using a , they are RBG and NIR images. My question is how can I calculate the reflectance for the images, the values are currently in digital numbers (...
- 744
0
votes
1
answer
437
views
Whole image cloud cover for LC8_SR?
I need to filter the LANDSAT/LC8_SR image collection using an assessment of total cloud cover in the entire scene of each image. i.e. each image in the collection is "in" or "out" based on a ...
- 3
2
votes
1
answer
2k
views
Sentinel-2 Reflectance calculation
What is the procedure for reflectance calculation from Sentinel 2 1C products downloaded from ESA Scientific Hub?
- 485
1
vote
1
answer
241
views
Landsat 7 - 8 surface reflectance bands from ESPA (LEDAPS)
I have downloaded some Level 1 and higher level imagery data including surface reflectance as well.
I should process these data in Idrisi (Selva) package.
The Level 1 images' pixel values are between ...
- 11
3
votes
2
answers
410
views
Strange reflectance values in Sentinel-2 images over sea ice
I am dealing with Sentinel-2 (Level 1C) images over sea ice. I have downloaded some and was wondering: When I look e.g. at Band 8A, there are some images where the reflectance over the water between ...
- 31
1
vote
1
answer
2k
views
Calculating Albedo for Landsat 8 using QGIS with GRASS?
I am trying to estimate albedo for Landsat 8 OLI. The idea was to use the GRASS function i.albedo within the processing toolbox of QGIS. However, the option for Landsat 8 OLI is not available, ...
2
votes
1
answer
106
views
Very low reflectance values landsat 7
I am getting very low reflectance values (mostly < 0.15) in all bands of multiple Landsat 7 scenes after having converted to TOA reflectance manually in ENVI. These values are not supposed to ...
- 103