Questions tagged [reflectance]
Reflectance is the ratio of incident flux and reflected flux from a surface
84 questions
2
votes
1
answer
1k
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 ...
CommunityBot
- 1
0
votes
2
answers
395
views
Convert Landsat 9 Surface Reflectance product DN to surface reflectance values
I downloaded the Landsat 9 L2 imagery from Earth Explorer for the purpose of calculating NDVI. However, when opened in ArcMap 10, the pixel values are in the range of 7000 to 45000. I understand that ...
CommunityBot
- 1
0
votes
1
answer
425
views
Normalized Difference Turbidity Index (NDTI) wrong
I'm trying to retrieve a turbidity indicator from a Landsat 8 using NDTI :
NDTI=(Red-Green)/(Red+Green).
The problem is the result is not consistent with the reality.
Here is a RGB visualization where ...
CommunityBot
- 1
1
vote
0
answers
49
views
What is the difference between surface reflectance and top of atmosphere (TOA) reflectance?
I was told that during winter it is better to use TOA because SR is not good for winter. But I didn't find any files describing it. Can anyone explain the difference of these two and why they perform ...
- 20.3k
1
vote
1
answer
394
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 ...
- 3
0
votes
2
answers
179
views
A method to match narrow bands from in-situ spectrometer with Landsat-8 central band
Is there a way to resample Landsat-8 bands to match different bands from a spectrophotometer. I'm doing atmospheric correction, comparing in-situ reflectance measurements performed using 10-nm wide ...
- 448
0
votes
1
answer
37
views
Why Skysat analytic surface reflectance products have wierd reflectance in shadows?
I have a skysat analytic_SR image. I did not get any .json file related to atmospheric correction parameters as they say. I can only get the Planet notes on planetscope for surface reflectance (see ...
1
vote
1
answer
60
views
Classifying Object Based on Mean IR Values
While Developing rule sets using e-Cognition for object classification for say; Landsat 7 images what are the threshold conditions to classify water, building, agriculture land & bare soil ...
- 330
1
vote
1
answer
2k
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 ...
CommunityBot
- 1
0
votes
0
answers
23
views
Low reflectance values
I use DJI P4 multispectral. Here is the command I gave in opendronemap software.
–dem-resolution 1.5 --orthophoto-resolution 1.5
–orthophoto-png --dsm
–radiometric-calibration camera
–texturing-skip-...
- 77.6k
1
vote
0
answers
81
views
Changing saved reflectance panel values in Pix4D [closed]
We have a Micasense rig for multispectral imagery, and when my coworker set up my Pix4D account & did a test run he used the wrong reflectance values for our calibration panel. Pix4D saves those ...
- 65.4k
0
votes
1
answer
246
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 ...
CommunityBot
- 1
1
vote
2
answers
1k
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 ...
1
vote
1
answer
72
views
Why the result of download for Sentinel-2 Cloud Removal doesn't show reflectance value?
I succeed to remove cloud from these step in :
https://developers.google.com/earth-engine/tutorials/community/sentinel-2-s2cloudless
Then I download the result. But, the result is not in decimal as ...
- 1,412
1
vote
1
answer
476
views
Getting reflectance from Sentinel2 L2A images
I want to get surface reflectance at some points on GEE for Sentinel2 L2A images. I know that I can use inspector to get band values at each point. I read that these values are Digital Numbers and ...
- 1,044
1
vote
0
answers
54
views
Reflectance median extraction on GEE on field values
I want to extract reflectance values of points for field measurment at different dates. I want to get the median reflectance value for each band for 1 pixel around the point to look for the link with ...
- 1,412
1
vote
1
answer
1k
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 ...
CommunityBot
- 1
0
votes
1
answer
604
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 ...
CommunityBot
- 1
1
vote
2
answers
870
views
Correcting Worldview-3 data to ground reflection/bottom of atmosphere with open source? [closed]
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 ...
- 65.4k
2
votes
0
answers
99
views
Viewing Angle Effect On Spectral Reflectance Sentinel-2
I am new to remote sensing and would like resources and literature explaining the effect of viewing angle on spectral reflectance for satellites. I have read the study by Moriya et al translated to ...
- 53
1
vote
3
answers
406
views
Determining surface that reflectance curve matches?
I was wondering to what surface that reflectance curve belongs?
It is definitely no water or snow since their reflectance drops at a much smaller wavelength.
I was thinking about a dense cloud but the ...
- 65.4k
2
votes
2
answers
842
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 + ...
- 41
2
votes
1
answer
204
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 ...
- 65.4k
2
votes
1
answer
827
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
0
votes
0
answers
141
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 ...
3
votes
1
answer
7k
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....
CommunityBot
- 1
1
vote
0
answers
58
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
1
vote
0
answers
40
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 ...
- 65.4k
2
votes
1
answer
3k
views
Sentinel-2 Reflectance calculation
What is the procedure for reflectance calculation from Sentinel 2 1C products downloaded from ESA Scientific Hub?
- 44.6k
4
votes
1
answer
2k
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 ...
0
votes
1
answer
62
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 ...
CommunityBot
- 1
1
vote
2
answers
1k
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 ...
- 81
5
votes
2
answers
2k
views
Dark Object Subtraction using Top of Atmosphere Reflectance?
I'm working on a WorldView 3 image in QGIS and have been told to use Dark Object Subtraction (DOS) to atmospherically correct it to surface reflectance using the raster calculator. I have the Top of ...
- 81
1
vote
1
answer
246
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, ...
CommunityBot
- 1
2
votes
1
answer
516
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 ...
CommunityBot
- 1
0
votes
1
answer
1k
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 ...
- 10.5k
10
votes
1
answer
1k
views
Landsat level-2 data comparison
I'm doing a temporal analysis of NDVI and temperature over 17 years, necessitating data from Landsat 5,7, & 8. I'm interested in using level-2 Landsat data available from https://espa.cr.usgs.gov/...
- 65.4k
14
votes
1
answer
7k
views
What is the range of values of Sentinel-2 Level 2A images?
I found in Level 2A Product Format Specifications Technical Note page29 that:
"The L2A Quantification Value is aligned with the L1C Quantification Value of the L1C product from which the L2A product ...
- 2,091
1
vote
0
answers
123
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 ...
- 65.4k
1
vote
1
answer
757
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(...
CommunityBot
- 1
1
vote
0
answers
307
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)) / ...
- 173
1
vote
2
answers
256
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 ...
CommunityBot
- 1
2
votes
0
answers
194
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 ...
- 65.4k
2
votes
1
answer
1k
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), ...
- 51.8k
10
votes
2
answers
26k
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 ...
CommunityBot
- 1
3
votes
1
answer
2k
views
NDVI analysis of LANDSAT 8 imagery in QGIS
I am trying to run an NDVI classification of 2015 multispectral LT8 imagery in QGIS to assess the quality of vegetation cover in regards to habitat suitability for a primate species in northern ...
- 131
0
votes
1
answer
49
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 ...
- 1,663
2
votes
2
answers
2k
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 ...
- 32k
0
votes
0
answers
116
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
12
votes
2
answers
533
views
Ice type differentiation using satellite data
I would like to classify glacial area by categories of snow (if there is) and ice, but what's most important: between old ice and fresh ice. They have different properties that are possible to ...
- 664