All Questions
Tagged with ndvi remote-sensing
101 questions
0
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12
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Landsat 8 C2 L2 FOR NDVI
When I download Landsat 8 C2 L2 image from USGS and apply directly NDVI formula the value is ok it is in range -1,+1 while where I am applying scale factor which is (0.0000275)-(0.2) for each band ...
1
vote
1
answer
57
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Direct use of Sentinel 2 L2A imagery for vegetation analysis
I am working on my research to calculate the green vegetation in the study area using sentinel 2 L2A 10m resolution. Do I need to perform any correction or smoothing before analysis?
- 13
0
votes
1
answer
66
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Does Landsat satellite image should have raster value to -1 and 1?
I am calculating the NDVI for Landsat-8 using the formula as shown below:-
But the pixel value rendered is as shown below: -
But the NDVI values need to be between -1 and +1 however, the value ...
- 83
1
vote
1
answer
52
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Monthly sentinel-2 Max and Mean NDVI, and B9 values extracted to CSV
When trying to run this code I get an error:
Expected Type: Image(unknown bands) actual type:ImageCollections
I would also like to maintain the ID column to be the ID column in my shapefile(labelled ...
- 13
1
vote
2
answers
584
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I want to test the statistical significance of the NDVI change in R
I have 20 Sentinel 2 satellite data for the period from 2017 to 2020, with 5 satellite scenes each for the months from May to September, covering one vegetation season. I am interested in whether the ...
- 23
1
vote
1
answer
512
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I want to apply Mann-Kendall test to NDVI of Sentinel 2 data in R
I have 20 Sentinel 2 satellite scenes from 2017 to 2020 with the months from May to September to cover the growing season. I calculated the NDVI of each scene and intersected it with my area of ...
- 23
1
vote
0
answers
11
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Managed aquifer recharge (MAR) and Remote sensing [closed]
What is the process to identify with quantitative data and remote sensing, how a managed aquifer recharge (MAR) has contributed to increased water availability, There is no local data and the area is ...
- 11
-1
votes
1
answer
1k
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Interpreting Green Chlorophyll Index vs NDVI
I am attempting to research the relationship between agricultural yields and household well-being, and I am using remote sensed vegetation indices calculated from LANDSAT images to do this. Whereas ...
- 93
0
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1
answer
156
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How to calculate and export a table of mean of the maximum daily NDVIs over a particular period
I am using code from Nina Kattler to calculate the mean of max daily NDVI in particular districts in Mali over the growing season in 2019. The original code gives the mean NDVI over the growing season,...
- 93
0
votes
1
answer
1k
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Change system:index of FeatureCollection ID in GEE to use Asset ID
I have a FeatureCollection with points loaded from an asset (shapefile). Since the system:index is empty, gee assigns a weird index to each feature (e.g. 000000000001, 0000000000a).Which causes ...
- 69
0
votes
1
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455
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Error in generating a chart: No images in the collection intersect the specified regions
I am getting an error saying:
no images in the collection intersect the specified regions
thus my time-series chart cannot be generated.
What might be the reason for this?
The link to my code
https:/...
- 69
0
votes
1
answer
389
views
Calculate transition of different NDVI classes from pre and post NDVI in Google Earth Engine
My competency in GEE is quite low. I have calculated 2 NDVI layers (pre and post-disturbance NDVI). I have separated these NDVI layers into 4 classes according to NDVI values. Now I need to calculate ...
- 57
1
vote
1
answer
1k
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Google Earth Engine - NDVI chart - projection error
Once I multiply NDVI and EVI values with 0.0001, I get an error that is shown below. So I can't get the chart.
Error generating chart: Projection error: Unable to compute intersection of geometries ...
- 15
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votes
0
answers
188
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Why do I get wrong NDVI, EVI values in crop monitoring?
I have been monitoring agriculture lands with Sentinel-2 S2MSI2A data. I'm calculating NDVI and EVI for the vegetation. The NDVI values are slowly increasing because the growing crops which is look ...
- 21
3
votes
1
answer
1k
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Calculate and extract layer of NDVI change in Google Earth Engine
My experience and expertise in Google Earth Engine are super low. My study area is Sundarban, Bangladesh. I have 2 NDVI from 2 years (2016 & 2017). I want to find the vegetation change by ...
- 57
4
votes
2
answers
908
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Landsat 8 appears to be "greener" than Landsat 5?
I noticed something strange in my NDVI time series. Here I plotted NDVI for some geometries of interest in European countries between 1985 and 2020.
You will see there is a noticeable jump in NDVI ...
- 87
0
votes
1
answer
716
views
NIR.subtract is not a function
I am trying to calculate Kernal NDVI (kNDVI) and the code keeps giving me this error.
The link to the code:
https://code.earthengine.google.com/24e8503ec2f264d0ffe0ba1bfe4c6353
/// adding shapefile to ...
- 69
1
vote
0
answers
1k
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Modified Chlorophyll Absorption Ratio Index (MCARI) vs Green Chlorophyll Index (GCI) in a desert
I am using UAV multispectral data to compute different vegetation indices. Both of these indices were computed with the purpose of seeing/assessing the chlorophyll content, thus indicating if the ...
- 1,244
1
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0
answers
385
views
MSAVI vs NDVI for deserts
I calculated NDVI (Normalised Difference Vegetation Index) and MSAVI (Modified Soil Adjusted Vegetation Index) for a desert environment, where most of the vegetation is shrubs with some trees using ...
- 1,244
2
votes
1
answer
542
views
GEE: projection error when exporting data to a table
I am trying to export some vegetation condition index data calculated from MODIS data on Google Earth Engine to a table, but keep getting the error:
Error in map(ID=3): Image.reduceRegions: Unable to ...
- 861
3
votes
3
answers
2k
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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 ...
- 31
2
votes
1
answer
493
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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 ...
- 21
0
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1
answer
166
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Why are my forest areas orange and non-forest areas green in Google Earth Engine?
I'm doing GEARS' 3rd lab tutorial on Remote Sensing in Google Earth Engine.
I calculated the NDVI of an area in Batchellor, Australia. The result is a black and white image so I added a color palette. ...
- 1,217
1
vote
2
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796
views
Interpretation of NDVI values
This might be a trivial question, but please bear with me. So I am using python and Sentinel images and I want to calculate NDVI, which is (NIR-RED)/(NIR+RED). So in the case where the final result ...
- 471
2
votes
1
answer
2k
views
Dealing with NAN values in my training dataset
I am new to remote sensing. I am working on a project where I need to perform land use land cover classification. For such a task I want to use machine learning (python).
My features contain 'BANDS' (...
- 471
1
vote
0
answers
48
views
The emissivity of snow
I try to use the NDVI Based Emissivity Method to calculate the LSE. But the function almost applied over surfaces composed by soil and vegetation. Over surfaces like water, ice, or snow did not ...
- 31
1
vote
0
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145
views
Whether NOAA AVHRR NDVI V5 already remove cloud?
We want to use NOAA/CDR/AVHRR/NDVI/V5 datasets for analysis, but we are not sure if the NDVI already remove the cloud and cloud shadow or not?
Need we use 'QA' to remove the cloud and cloud shadow ...
- 11
1
vote
1
answer
295
views
Is the Enhanced Vegetation Index normalized?
I am trying to figure out if the Enhanced Vegetation Index (2-band) is normalized or not? My first guess is that it is, but due to a multiplication factor of 2.4, I'm not sure if it is or not. The ...
- 503
0
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1
answer
184
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Produce NDVI on Landsat1 satellite images?
Does someone have any experience to produce NDVI on the Landsat1 satellite image? What kind of atmospherical correction (on Landsat 1) technique is necessary to perform before producing indices? Is it ...
0
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1
answer
447
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 ...
- 17
2
votes
1
answer
200
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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:...
- 151
0
votes
1
answer
59
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 ...
- 67
0
votes
1
answer
422
views
EVI2 value calculated from MODIS MOD09Q1 not bounded by -1 to 1
I'm trying to derive from MODIS 8 day composite MOD09Q1.006 product
My formula follows the standard interpretation:
EVI2 = 2.5(NIR-Red)/(NIR + 2.4*Red+1)
I already know that MODIS bands for NIR ...
2
votes
1
answer
522
views
Aggregating/Averaging NDVI across pixels. Arithmetic mean seems bad choice
I need to compute an aggregate index for vegetation density in certain (large) shapes, to assess desertification. I have NDVI data at a high spatial resolution (~100 NDVI-pixels per aggregation shape, ...
- 289
0
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0
answers
176
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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 ...
7
votes
1
answer
779
views
Which NIR bandwidth is suitable to Calculate NDVI?
Often we encounter multi-spectral and hyper-spectral sensors offering multiple NIR bands. For instance, the WorldView 3 sensor has 8 MS bands, out of them, two bands fall within NIR region.
Near-IR1: ...
- 1,218
2
votes
0
answers
482
views
NDVI calculation problem
I have photo created by UAV, and I want to calculate bNDVI:
(NIR-blue)/(NIR+blue)
I have these bands (filter is ok -100%). So using QGIS I have values -0,1-> 0,3 - but bNDVI must be from 0,65->0,...
- 21
3
votes
2
answers
308
views
Vegetation Index for dry and sparse vegetated areas?
I found many different index for the estimation of vegetation cover, but many of them struggle in sparse areas with low vegetation cover, as the soil signals are way stronger than the vegetation ...
- 390
0
votes
2
answers
5k
views
Export time-series MODIS 16 Day NDVI and EVI Data on Google Earth Engine [duplicate]
I want to extract every single MODIS 16 Day NDVI and EVI Data image on a particular area from 2000 to 2016. I was able to filter image collection but I do not know how to export every single image on ...
1
vote
1
answer
730
views
Landsat level-2 NDVI valid range with saturation
I have Landsat level-2 NDVI tiles I am using in ArcMap 10.4.1.; however, the level-2 NDVI data in ArcMap ranges from -5,189 to +20,000.
The spectral image product guide (which I've linked) says that ...
- 425
1
vote
1
answer
3k
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Processing LANDSAT 8 data in R (using packages Raster, RSToolbox, etc.) in order to calculate NDVI and land cover classification? [closed]
I am analyzing several LANDSAT scenes from the LANDSAT 8 OLI mission (18 in total, all from Jan 2017 - cloud cover < 20%).
I now want to calculate the NDVI and do some land cover classification on ...
- 577
2
votes
1
answer
450
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Landsat Collection 1 Level-1 or Landsat Collection 1 Higher Level?
I want to use NDWI and NDVI index in my study for a time-series analysis using all products available (Landsat 5,7 and 8).
Can I use the product Landsat Collection 1 Level 1 for my analysis or
...
- 41
4
votes
1
answer
742
views
Why getting wrong NDVI values resulted from scaled reflectance in ArcMap?
I have made atmospheric corrections to my Landsat 8-OLI raster using 'ENVI FLAASH' having surface reflectance values scaled between 1-100.
In ArcGIS I am using simple expression to compute NDVI ...
- 1,218
3
votes
2
answers
4k
views
Do clouds reflect NIR/Red bands
When using Landsat 8 imagery to calculate NDVI, will the NIR and Red bands be affected by cloud cover?
In other words, will clouds produce a wrong NDVI calculation?
- 335
1
vote
1
answer
207
views
Cleaning up polygon generated from NDVI raster
So I have NDVI raster files for about 1000 acres of vineyards we manage. What I have done is created a model that takes the NDVi raster, reclassifies it to isolate out the areas of high vigor, then ...
- 31
1
vote
1
answer
1k
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calculate NDVI for several images
I want to calculate NDVI for 50 Landsat 7-TM images . I have done a stack layer for each band of 50 images using envi software and then calculate NDVI for the stack of two bands demanded in NDVI ...
- 19
1
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0
answers
54
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What is the best way NDVI can be used for assessment of remediation level of ecosystem (after nuclear accident)?
I am thinking about ways to assess efficiency of various bioremediation methodologies and self-remediation of an ecosystem polluted with nuclear waste.
I would like to use NDVI as an assessment ...
- 42
1
vote
3
answers
1k
views
Processing landsat 8 to make NDVI in R
I want to do the NDVI with images landsat 8 in R, radiometric correction, radiance and reflectance, I make it from the models of the USGS (model here)
But taking the image (ND) for the calculation of ...
- 316
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/...
- 425
0
votes
1
answer
839
views
Using scale and offset values of MODIS products
I'm working on NDVI data from MODIS_13Q1 product. As far as I know, NDVI data has scale and offset values. I used these values to get geophysical values of pixels.
My problem is after processing ...
- 135