Questions tagged [ndvi]

Normalized Difference Vegetation Index is used to quickly identify vegetation and its condition in remotely-sensed data.

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2answers
665 views

Calculate NDVI image from R and NIR channels and rescale it to 0-255

I have images of plants taken in Red(R) and Near End Infrared(NIR) field, I calculate the NDVI image per pixel using the below formula, NDVI = (R-NIR)/(R+NIR) , for all pixels, I get a range ...
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1answer
1k views

Mask clouds in LandSat 8 surface refletance image

I would like to know how to remove the clouds in a ImageCollection of LandSat 8 Surface Reflectance (SR) image and create a single image without clouds using google earth engine, to calculate NDVI. I ...
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2answers
158 views

NDVI values obtained with different sensors

In a research paper with NDVI values, differences were found for the same pixel between Landsat 5, Landsat 8, MODIS or Sentinel made after the corresponding atmospheric corrections. Can this be right? ...
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2answers
814 views

Splitting picture taken with regular digital camera into real spectral RGB channels?

I have no idea how the sensors inside a camera work. I know I can take jpeg and separate the R, G and B channels but I have no idea whether these channels are the real red, blue and green in visible ...
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2answers
1k views

How to create an image of mean values from multiple NDVI images?

I have downloaded MODIS NDVI images of 12 months. I would like to create just 1 image with the mean values. I tried using IDRISI's 'NDVI compositing utility', but I get an error. Is there a way to do ...
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2answers
3k views

Extract pixels from NDVI in ArcMap

I have a NDVI that I created from a Landsat 5 image. Is there a way to extract all the pixels above a certain threshold and save it as a shapefile? I am trying to create a vegetation mask of sorts to ...
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2answers
665 views

Making stack from many images in Google Earth Engine?

Using the code below, I've computed 20 ndvi images for modis data. How can I stack and save them in a single file? var mod13 = ee.ImageCollection("MODIS/006/MOD13Q1") .filterBounds(geometry) ....
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1answer
75 views

Purchasing NDVI imagery for South Western England? [closed]

I am working on a project developing an application for livestock farmers where they can monitor their feed using satellite data. The main aim is to calculate the biomass of a field of grass. The ...
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2answers
50 views

ArcGIS: NDVI average for bare soil

In ArcGIS I have a 3 Landsat NDVI datasets for 3 consecutive months and would like to calculate the mean bare soil (in hectares) for which I have manually worked out to be between the values of 105 ...
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2answers
436 views

NDVI data for UK?

I am looking for monthly composite NDVI data for the UK between 2000 and 2013. The resolution is not so much of an issue. I am struggling to find relevant data and images for further processing in ...
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3answers
3k views

Convert NDVI raster data to shapefile

I apologize in advance for my lack of knowledge. I don't know a great deal about working with this program, so I'm learning as I go. I am wanting to take the free Landsat data that I have downloaded ...
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3answers
364 views

Analysis MODIS NDVI - MOD12A2

I am trying to analyse the images that I downloaded from MODIS, which are the Vegetation Indices 16-Day L3 Global 1km. With this data I want to analyse the change in vegetation over the years in a ...
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1answer
3k views

How to process MODIS ndvi data using QGIS/GRASS/R?

I have MODIS ndvi data (MODIS_Grid_16 days NDVI) from the iberian peninsula (3 tiles), from February of 2000 to August of 2012 (really big data). I want to know how to deal with this kind of files. My ...
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1answer
31 views

ArcPy: Create NDVI with Raster Calculation and Map Algebra

My target is to create NDVI Rasters but I'm stuck with python loops, since I'm new to that, so sorry for a maybe basic question. I have 2 folders, one with rasters (tif) with the red band, the other ...
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2answers
189 views

Google Engine - Make a greenest pixel composite for Sentinel 2

Does anyone know how to do a composite of greenest pixel for Sentinel 2? That is calculate the maximum NDVI for a Image collection, and then do a pixel-wise image stacking of the original bands (...
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1answer
670 views

I need to add a sentinel-2 image into Google Earth Engine Explorer with a specific ID

I'm new at Google Earth Engine and Javascript. I am using the graphical user interface of Google Earth Engine (Explorer) to obtain NDVI using sentinel 2. My study site is somewhere in Peru with an id:...
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1answer
297 views

MODIS data for entire Earth Surface with ModisDownload in R

I am trying to use the ModisDownload function from the rts package to download, mosaic and reproject NDVI data from MODIS for the entire Earth surface. I have successfully done that for a subset ...
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1answer
1k views

How to apply a Cloud Mask in Google Earth Engine? (Landsat 5 TM 8-Day NDVI Composite)

I need to download ndvi values for some pixels for 2000-2001 using the Landsat 5 TM 8-Day NDVI Composite, but since there is no quality band as in mod13q1 there's no way to filter by quality. ...
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1answer
300 views

Computing NDVI - Repeated calculation error message (Google Earth Engine)

I am doing simple calculation for NDVI using Landsat 7 TOA Reflectance (Orthorectified). Landsat seven has the following bands: B1-Blue, B2-Green, B3-red and B4-nir. I used the following code: //...
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1answer
2k views

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 ...
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3answers
884 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 ...
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1answer
230 views

Can you apply Maximum Likelihood classification to NDVI? [closed]

Can the ML be applied to an NDWI image? Or is it a separate means of classifying that is only applied on 2 or more bands? The problem I am actually facing is that without knowing that this could be a ...
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2answers
619 views

Using ArcGIS Raster Calculator to calculate MSAVI2 based on Landsat 8 OLI bands 4 and 5

I would like to calculate a Modified Soil-Adjusted Vegetation Index 2 on the basis of Landsat 8 OLI imagery, bands 5 (NIR) and 4 (RED), using the Raster Calculator. The formula should be: I have ...
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1answer
558 views

Calculating maximum value in Raster Calculator of ArcGIS for Desktop?

I have MODIS NDVI data of four months and I have to calculate NDVImax. I am using the Raster Calculator of ArcGIS and have been using various algorithms like [MAX ("june2000", "july2000" , "...
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1answer
273 views

Higher NDVI than SAVI [duplicate]

I have calculated NDVI and SAVI for landsat-8 image. But I am getting higher value of NDVI than SAVI Can you tell me reason for this NDVI=0.46 SAVI=0.34 Specific band pixel values are toa b4- 0.130 ...
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1answer
4k views

EVI and NDVI range value

I've used a Landsat 8 image for vegetation analysis in an urban area. I've got a large maximum number of EVI value as shown in this image: Is this normal in calculating EVI and NDVI? Because I know ...
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1answer
3k views

Generating NDVI with multi channel images?

I have a 6 channel proprietary camera and I need to create a NDVI map. I created a map from each band, so now I have 6 files each one on a different band width. How can I proceed now using QGIS?
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1answer
42 views

How to compute the conditional function and output binary image in GEE?

I am now using Google Earth Engine to process the Landsat 8 images. Now I have calculated NDVI, EVI, mNDWI and generated some maps. I am now want to generate a function based on those indices values, ...
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1answer
98 views

Smoothing/interpolating across images in an ImageCollection to remove missing data

I have some code that is working properly to calculate the monthly NDVI averages for the previous two years from a date but I sometimes have missing data in some of the months and I would like to get ...
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1answer
339 views

Analyze time series NDVI using bfast

I would like to study a trend of NDVI data for a specific time interval using bfast package. For this final aim, I read about the necessity to convert my data frame into a time series object in R. ...
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3answers
327 views

Classifying NDVI image using ArcGIS Desktop?

I am creating a variety of NDVI for different periods in time, so per season for four years. I used the raster calculator on arcgis but i keep getting different max and min values. Do I need to make ...
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1answer
110 views

Is it possible to create one single NDVI image out of multiple NDVI images?

I am working with Landsat 8 images to create seasonal NDVI images in QGIS. For all NDVI images I masked the clouds/cloud shadows so there are 4 different NDVI images with different cloud/cloud shadow ...
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1answer
270 views

DOY chart in Google Earth Engine

With the following code I am trying to produce a NDVI graph with the days of the year on the x axis (based on this example, 2nd graph). var modisNDVI = ee.ImageCollection ('MODIS/MCD43A4_006_NDVI'); ...
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2answers
570 views

Calculating NDVI using Landsat 8- Cloud/Atmospheric Correction

System: Windows 7 Software: Arcmap 10.4.1 Data: Landsat 8, NDVI calculations I am attempting to calculate the NDVI values over my state over a period of 3 months. Naturally, there are going to be ...
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1answer
266 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 ...
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1answer
105 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 ...
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1answer
417 views

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 ...
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1answer
310 views

Calculating plant proportion Landsat

I have this paper. In equation 2 they are calculating surface emissivity. I want to ask what is 𝑷v plant proportion? https://www.researchgate.net/file.PostFileLoader.html?id=...
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1answer
371 views

Getting Landsat NDVI data processed with LEDAPS on USGS earthexplorer

I am trying to download NDVI values from Landsat on the earthexplorer. I read there were higher-quality NDVI series processed with the so-called LEDAPS algorithm. The page from the LEDAPS website ...
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1answer
879 views

Remove raster pixel in R

This is the 32 year trend NDVI (raster data) I would like to remove the green grids data by using R (the green pixel value is larger than 0.03) and this one is R code that i use but i cannot remove ...
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1answer
209 views

Doubt in MODIS NDVI range [duplicate]

MODIS-NDVI product MOD13Q1 shows range from -1986 to 9976 but NDVI ranges from -1 to 1. What these value means? What do I need to do as corrections? I have attached an image showing MODIS-NDVI ranges ...
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1answer
152 views

Matching Decedal Average NDVI and Worldclim Data

Ive never used NDVI (or EVI) datasets in R. Does anyone have any resource I could use to access a decadal average NDVI dataset for the globe. It would be preferable if this dataset was also comparable ...
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1answer
412 views

Resampling 30 m NDVI to 5 m in ArcGIS [duplicate]

Is there any easy way to resample 30 meter NDVI from Landsat 8 images to 5 metres? I use raster to point and the interpolation of point to raster using Kriging method. I know that it may not be a ...
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2answers
2k views

Classification, change detection and NDVI using landsat 2 (MSS), landsat 5 (TM) and Landsat 7 (ETM)

I have 3 Landsat images for the same area. One in 1972 (landsat 2 mss), one in 1996 (landsat 5 TM) and one in 2010 (landsat 7 ETM). I would like to detect changes in land cover and create diachronic ...
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1answer
25 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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1answer
20 views

Image analysis about area

I tried to find out the lake's area in an image raster - I used NDVI and reclassify then I got a whole value file like this. Is there anyone can tell me how to divide them to each polygon? Or I can ...
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1answer
85 views

Pixel wise NDVI calculation in GEE

I have a collection of Landsat images filtered over forest regions of India over a time interval of 6 years(2013 - 2018). I have again filtered this collection such that I have one image per 4 months, ...
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1answer
34 views

Dictionary.toArray: Unable to convert dictionary to array, key 'NDVI' has a null value

I am trying to reduce a region by clipping an image from copernicus to get NDVI and then calculate a Kc value. However, Once I use a polygon I imported with the "Draw a Shape" tool, the calculations ...
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1answer
32 views

NDVI in landsat image not in range(-1,1)

Using ENVI 5.3. I have done a radiometric calibration(radiance) and flaash atmospheric correction then a seamless mosaic and subsetted data from ROI. I then calculated the NDVI. My results in May 2017 ...
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1answer
38 views

Access layer of raster stored in memory using ArcPy to create NDVI from subset of multi-band raster

I am trying to create a final output of an NDVI raster for a number of Landsat images run through a for loop in Python 3 (for ArcGIS Pro). I am able to produce the NDVI rasters when I save the ...