Questions tagged [ndvi]

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

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23 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 ...
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20 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 ...
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46 views

Processing NDVI in Google Earth Engine

I would like to analyze NDVI in the region of Bangkok. Here is the code : { //Define time range var startyear = 2006; var endyear = 2016; //Set date in ee date format var ...
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15 views

Produce NDVI on Landsat1 sattelite images?

Does someone have experience with producing NDVI on the Landsat1 satellite image? What kind of atmospherical correction (on Landsat 1) is necessary to perform before producing indices? Is it possible ...
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36 views

Extracting monthly NDVI data using Google Earth Engine

I am using the following code to extract yearly NDVI. Is it possible to extract the monthly data? // Map a function to select data within the year and apply mean reducer var byYear = ee....
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55 views

Extracting NDVI over time using Google Earth Engine

I am trying to extract NDVI data for provinces in Cambodia over time. The following codes work for a specific year (2002). Can someone show me a better way to collect the data over time ...
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1answer
66 views

Reduce.region odd result in GEE, however the map seems to be correct

I'm using Google Earth Engine to calculate the 5th and 95th percentiles of the intraannual coefficient of variation (CV) of the NDVI within a polygon (my area of interest). My code actually runs and ...
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109 views
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Land Use classification using Google Earth Engine

I have calculated NDVI using land cover classification, now I want to calculate NDVI for Land-Use Map. I am using Google Earth Engine and can't find any help for that. If I use a city 'Mumbai, ...
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30 views

Map NDVI from MODIS image for a specific country

var dataset = ee.FeatureCollection('USDOS/LSIB/2013') .filterBounds(ee.Geometry.Point(-7.681, 53.43)); var image = ee.Image().float().paint(dataset, 'iso_num'); var visParams = { palette:...
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1answer
39 views

NDVI from Google Earth Engine

I want to get the NDVI of MODIS from Google Earth Engine in a country (Ireland), here is my code. It works, but it doesn't show on the map. var dataset = ee.FeatureCollection('USDOS/LSIB/2013') ...
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1answer
166 views

Which output data type to choose in QGIS SAGA Raster Calculator in Batch Mode?

I have 5 years of MODIS13Q1 NDVI .tiff images for time series analysis. I want to multiply all the images with the scale factor of 0.0001 before using them. In order to process all at once I try to ...
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412 views

Faulty Landsat 5 and 7 NDVI/ EVI archives in Google Earth Engine

For my research, I need to use NDVI or EVI datasets in Google Earth Engine. I found Landsat 5 and 7 datasets (8 day, 32 day, anual) for both. However, no matter which combination of datasets and dates ...
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1answer
65 views

NDVI time series chart showing multiple values for the same point in Google Earth Engine

I tried to generate a time series chart of NDVI using Sentinel-2 data for multiple points. But the chart has vertical plots with two values for same point and same date. Here is the code: var ...
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1answer
29 views

Google Earth Engine Greenest Pixel Mosaic Landsat 5 - Error: Image.select: Pattern 'NDVI' did not match any bands

Using the standard Earth Engine Quality Mosaic function I have successfully compiled Greenest Pixel mosaic for multiple years using Landsat 8 and Landsat 5. However recently I encountered an issue ...
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Printing NDWI and NDVI comparision graph

Trying to print the chart for both NDVI and NDWI function addNDVI(image) { var ndvi = image.normalizedDifference(['B4', 'B3']); return image.addBands(ndvi); } ...
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1answer
47 views

Layer error: Number.divide: Parameter 'left' is required. error when print the dictionary

I have code that calculates NDVI, then calculate statistics inside a dictionary and then based on statistics calculte 3 layers that later on mosaiced. The problem is that for some reason I get this ...
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1answer
77 views

Citing greenest pixel composite images derived from Google Earth Engine?

I am using two greenest pixel composite images via Google Earth Engine for a project but am unsure how to cite this data. Do I cite it as regular Landsat data?
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2answers
34 views

Max NDVI per month & year using Google Earth Engine to CSV - CSV gives -999 values only

This question refers to Calculating NDVI per region, month & year with Google Earth Engine I have modified the code posted by @Kel Markert at https://code.earthengine.google.com/...
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1answer
64 views

Calculating NDVI per region, month & year with Google Earth Engine

This question refers to post: https://stackoverflow.com/questions/53280885 on stackoverflow. It was recommended by a user to repost here. I have modified the code posted by @Kel Markert https://code....
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2answers
49 views

Reclass NDVI value using a function

I'm trying to reclass the values of a sentinel 2 NDVI creating a function but I don't know exactly how do to it. What I exactly want is: When NDVI values are between -1 and 0, return (-1) ; 0 and 0....
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22 views

Print NDVI pixel value to an app ui.panel

I want to print the NDVI pixel value of the current image in a collection animation to the ui.panel link to the code it should look like: "NDVI Value is: 0.345" I have two problems 1. I don't know ...
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1answer
45 views

Creating NDVI from raster using ArcPy

I have to create NDVI's for multiple raster images, and so want to find out the most efficient way to do it. The code below works, but I wondered if there was a more efficient way to do it? # ...
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1answer
24 views

Merging two ImageCollections to create a new index

I am currently trying to calculate the rain use efficiency index for the years 2000-2015 with a Landsat dataset (NDVI) and a CHIRPS (precipitation) dataset. I already have two image collections ...
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1answer
51 views

Reclassify NDVI and count number of pixels above certain threshold in Google Earth Engine

Following on from a previous question (NDVI reclassify with mean +1SD as threshold in Google Earth Engine) I have managed to show the pixels that have value higher than NDVI mean+1SD at the estuary ...
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1answer
507 views

How to create C factor (RUSLE) map by using NDVI values?

I have a basic knowledge of GIS and ArcGIS sofware and I need to generate C factor (cover management factor of RUSLE) by using NDVI values. I know there is an exp formula but I don't know the steps to ...
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1answer
50 views

Calculating NDVI using Rasterio, Python

Below is my code for calculating NDVI using Landsat 8. I have used band 4 and 5, but I am not getting any output. How should I get the output image? import numpy as np import rasterio import ...
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204 views

Growing Season Length in Google Earth Engine?

I am trying to estimate growing season length with the MCD12Q2 dataset (Land Cover Dynamics Yearly L3 Global 500 m), which includes dates for the start and end of the growing season (...
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1answer
61 views

Different min and max NDVI values with different approaches using Google Earth Engine

I'm trying to calculate the vegetation fraction for land surface temperature calculations of a single Landsat 8 image. I need to find the min and max NDVI of the scene. I've masked the image and ...
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1answer
674 views

How do I convert 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. My question ...
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1answer
69 views

NDVI reclassify with mean +1SD as threshold in Google Earth Engine

I'm trying to do ndvi reclassify in google earth engine. I know exactly how to do it in Arcgis but I'm very new with GEE and I got stuck with javascript. What I want to do is to use mean + standard ...
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19 views

Batch downloading LANDSAT imagery based on nearest image capture date

I have a 30-year large dataset (100,000+ points) of insect outbreaks (0=no out break, 1= outbreak) throughout Australia. I am interested in seeing if the spatial configuration of vegetation is a ...
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1answer
38 views

Collection.toList: The value of 'count' must be positive. Got: 0

I have a code that suppose to count number of pixels in a polygon and to add it to the polygon as a dictionary. First NDVI calculted and then differrent ranges inside the polygon should be calculte: ...
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24 views

Iteration between different polygons in one layer

I am trying to create a code that will calculte the mean NDVI value for each polygon,the standard deviation , then std/2 and then will classify the pixels inside each polygon according to the next ...
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35 views

Min NDVI estimation from NDVI time series

I'm trying to estimate max min NDVI values from the NDVI datasets that came from Landsat images 4-5-7-8. For the max NDVI I used the "qualityMosaic" and it seems that it works okay, but for the min ...
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20 views

Are there annual or monthly NDVI high res datasets? [duplicate]

I'm looking for a source of high res (250 meter seems the highest res available for MODIS?) NDVI composite datasets for either an entire year (or monthly snapshots) if not, in a format I can import as ...
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1answer
40 views

Create Layer of pixels with value higher than 0.3

I have code that suppose to calculte NDVI and calssify it according to the NDVI value. I have tried to add a function that will create for me a new layer that will have only pixels with value higher ...
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13 views

Export results of MPRI and NDVI to CSV file? [duplicate]

How can I export the result of MPRI or NDVI (which are rasters) to a CSV file? I want to interpret and compare MRPI and NDVI.
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21 views

Why is ReduceRegions returning null values when I reduce using a feature collection?

I am running a landtrendr script which returns some disturbance-related values (year of disturbance, duration... among others) for an area. I would like to reduce the result of the area by a large ...
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21 views

Looping workflow across attribute table using Google Earth Engine

I have a shapefile asset loaded with an attribute column called "OBJECTID". I would like to run the following script for every ID number in the attribute table, and produce an output table. /// ...
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1answer
95 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
54 views

Update image visualization parameters from slider UI elements in Earth Engine

I'm trying to change the visualization parameters (min and max) of NDVI images in an Earth Engine App with slider controls. The result is an animation of styled images. The animation part works well, ...
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1answer
28 views

Losing pixels values when counting by value

I have a script that calculates number of pixels with NDVI values that are higher than 0.3, 0.5 and 0.7. My code runs with no errors, but it get value 0 and doesn't really count. what can be the ...
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2answers
949 views

Applying pixel reliability mask to time series MOD13Q1

I am working with a 23-band GEOTiff in which each band is a 16-day MVC MODIS NDVI image. The MODIS .hdfs include a "pixel reliability" image with the following values: [-1]: Fill/No Data-Not ...
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1answer
179 views

Calculating statistics for multipolygon in Google Earth Engine?

I have a shapefile which contains many crop plots, around 2000. I need to calculate NDVI (normalized difference vegetation index) and then calculate statistics for each one of the 2000 plots ...
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2answers
3k views

Producing NDVI maps in QGIS

I'm trying to produce a simple NDVI map in QGIS using a Macbook pro (2011) from landsat raster images. I've tried using the 'Measuring Vegetation' plugin, but for some reason that goes absolutely ...
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2answers
76 views

Visualize Image Collection

I have created image collection in GEE of LANDSAT 7 NDVI (LANDSAT/LE07/C01/T1_8DAY_NDVI). I chose date range and I know I have 71 images in the image collection. Is there any way to clip all the ...
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1answer
44 views

Export fitted values from time series regression in Google Earth Engine

I have used harmonic regression to model NDVI values in GEE. Now I would like to export fitted values for every half-month timestep. Unfortunately, much of the exported cells rasters have 'nodata', ...
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1answer
201 views

GEE - Add image band (NDVI) from one ImageCollection to corresponding image in an other ImageCollection

I have two ImageCollections one from Sentinel-1 and the other from Sentinel-2. From S-2 i derive the NDVI. I want to add the NDVI band from the S2 Collection to the Sentinel-1 ImageCollection with the ...
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1answer
168 views

problem with sentinel-2 NDVI export to TIFF in Google Earth Engine

I'm trying to calculate and export NDVI rasters extracted from Sentinel-2 using the script: https://code.earthengine.google.com/a9247db3f03e9514eb0378d1f59e9447 Source code: Export images in google ...
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1answer
43 views

Add an NDVI band to NAIP imagery and then chart it (using Google Earth Engine)

I am attempting to calculate NDVI from NAIP imagery, add the NDVI band as an additional band to the NAIP imagery and then chart it. I am easily able to calculate NDVI from NAIP imagery with the below ...

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