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Questions tagged [ndvi]

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

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15 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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0answers
12 views

Pixel-based NDVI time series - Google Earth Engine

I am a newcomer using GEE and now I want to do a NDVI time series. The condition is that it must be based on the result of the pixel, and it need to displayed on the map. I just made the NDVI time ...
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24 views

Using MODIS daily surface reflectance to create a NDVI timeseries in Google Earth Engine [on hold]

I am looking to develop a script to create an NDVI time-series using MOD09GQ.006 Terra Surface Reflectance Daily Global 250m for a given geometry variable. Additionally, I would like to filter out ...
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1answer
36 views

Finding monthly NDVI anomalies in Google Earth Engine?

I am using 16 NDVI data from GIMMS 3rd generation, and I wish to somehow visualize monthly anomalies (Difference from long term means greater than .5). I have plotted a time series of the data running ...
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1answer
39 views

Raster Statistics in GEE

I have created many rasters in Google Earth Engine that represent the NDVI. I want to apply statistics on them. I want to count how many pixels I have in every raster, and then I want to count how ...
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1answer
49 views

Interpolate the gaps among NDVI values [closed]

I want to calculate the Crop Water Requirements and for this I need NDVI values for a period of time. Because I have Sentinel 2 images and the temporal resolution is 5 days, I need also the values ...
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1answer
29 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 ...
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1answer
47 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
21 views

Make a loop in Google Earth Engine for reduce NDVI from year a months?

I have this code, it generate N ImageCollection and for each image a chart from NDVI in function a the months This is the place of study: var areaEst = ee.FeatureCollection("users/aleszczuk/...
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1answer
24 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
41 views

Getting NDVI data only for March from 2000-2003 using Google Earth Engine? [duplicate]

I have a polygon and I want to calculate its mean NDVI values from 2000-2003 (and few more periods) but only for March so the final result should be image which contains the mean NDVI values only for ...
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1answer
30 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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4answers
62 views

Determining NDVI of polygon using ArcGIS Desktop?

I have calculated the NDVI of a city. Now I want to know how "green" every street segment in that city is. I therefore buffered 7.5m on every street segment. I then used the Zonal Statistics as a ...
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1answer
51 views

Convert Landcover Raster to Vector to Use for Tracking NDVI Over Time

I want to look at NDVI and other spectral indices over time and compare these time series across different land cover types. I believe I have the code to do this but I'm running into the error that I ...
3
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1answer
56 views

Differences and thresholdis of ImageCollection in GEE

I have the following code (very basic as I am new user), and I want to create an NDVI difference collection by subtracting every NDVI image from my initial collection, with its previous one (something ...
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0answers
43 views

R MODIS MOD13Q1 - How to handle data quality issues?

I'm running into some issues with 250m 16-day MOD13Q1 NDVI data using the MODIS package in R. Looking at the following raster plot, there are certain days where the NDVI does not match the true ...
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1answer
85 views

Rasterio.features.rastersize

I have to transform the list of polygons that is in vector form into a raster mask that should be geographically aligned with the NDVI image that I have. I was advised to use rasterio.features....
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2answers
96 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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0answers
16 views

Error in compareRaster(rasters) : different extent

I'm having this error in NDVI tif layers, however, all the layers have the same extent and resolution. The only difference is an elevation layer (Aster_DEM_UTM).
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1answer
170 views

Earth Engine landsat 8 NDVI Time Series// multiple daily data points

When charting a time series based on Landsat 8 NDVI data over the course of yearly increments inside a polygon, the charts that I get have multiple data points on singular days. I've tried to reduce ...
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0answers
66 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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0answers
35 views

Landsat 8 Mosaic (NDVI) Overlapping?

I have downloaded 3 satellite images (Landsat 8 OLI TC1P), in three different periods (two images are from Mart 4. 2017. and the one is from Mart 20. 2017). I have joined (made mosaic) them in ENVI ...
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1answer
57 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
70 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
137 views

Create animation of NDVI from ImageCollection in GEE

I'm trying to make an animation of NDVI images from sentinel collection in order to see clearly variance in the field. The first part of the code works with little error: "Layer name is not a string: ...
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1answer
26 views

Merging NDVI classified and unsupervised classified image?

I have clipped forest area from an image and apply NDVI classification on forest area and in the remaining, I have done unsupervised classification. So, I want to know after NDVI and unsupervised ...
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1answer
88 views

Counting number of pixels with negative NDVI value within polygon using Google Earth Engine?

I have made a map of vegetation loss and gain for a polygon in Google Earth Engine using NDVI and would like to calculate the area where loss occurred. I attempted to use the reducer to get the sum of ...
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1answer
164 views

Make a Loop for Monthly NDVI in Google Earth Engine?

I've computed maximum NDVI for each month. but I don't know how can I write this code through a loop in Google Earth Engine? code link: https://code.earthengine.google.com/...
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1answer
65 views

Can I use a greenest pixel or a no clouds Sentinel 2 for NDVI analysis?

Can I use a greenest pixel or a no clouds Sentinel 2 for NDVI analysis? I want to use it for extract spectral signature. And now that I´m asking about it, I want to know if I can work classification ...
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0answers
15 views

Atmospheric correction using ERDAS 2014

There are some questions about atmospheric correction using ERDAS. Is it possible to use the atmospheric corrected satellite image to calculate NDVI and LST using ATCOR of ERDAS? If not, I wonder if ...
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1answer
74 views

NDVI index based on QA bands for MCD43A4 , in GEE

I want to calculate the NDVI index based on the MODIS/006/MCD43A4 collection and based on quality bands, but as a new GEE user I have no idea If I am on the rght way to do this. So far I have the ...
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1answer
45 views

More information about GEE dataset needed

I have a rather basic question, in relation to the MCD43A4 006 NDVI dataset in GEE. I am aware of the methods used for the generation of the BRDF MODIS dataset, but I would like to know more details ...
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1answer
121 views

Perform Radiometric Correction of Landsat images using ArcGIS Desktop

I need to run NDVI on a study area that is covered by more than one Landsat image. The NDVI must also be run over numerous years using different Landsat sensors (eg: Landsat 7 Level 1, Landsat 4-5 ...
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0answers
61 views

cloudless maximum-value NDVI-composite and saturating values

My aim is to compose cloud free maximum-value NDVI-composite from Svalbard, Norway. Composite is based surface reflectance collection, filtered with dates (growth period) and region of interest. When ...
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1answer
29 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 ...
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1answer
49 views

Point data extraction and printing as a TABLE

I am working with MODIS-NDVI image collection in Google Earth Engine. Below, you can find a script which is creating a chart of NDVI values over the given period for particular location. I would like ...
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2answers
71 views

How to classify entire pixels within loaded polygons as a feature collection, in Google Earth Engine

I need to determine the Modis pixels that enter whole within the polygons contained within a feature collection. I also need to determine those who don't fully enter. Apologies for English This ...
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2answers
123 views

Google Earth Engine: how to select NDVI for some land cover type

I am quite new to both Google Earth Engine and JavaScript. My goal is to obtain the NDVI just for some region (some polygon) only in the selected cover type. I managed to compute areas and number of ...
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1answer
78 views

Select observations based on Quality Bands , Google Earth Engine

From the following NDVI collection, I want to keep only the observations with Good Quality (equal to zero). I try to do this with the SummaryQA but I get "Pattern 'SummaryQA' did not match any bands"...
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1answer
92 views

Unable to transform features into projection, Google Earth Engine

I have the following code with which I try to export the MODIS NDVI index. I have rescaled the collection with the appropriate scale factor and code runs without errors. When I try though to download ...
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0answers
30 views

How to retrieve GIS data in Multiple Orthophoto at point level

I have been using a python script that can read Data from Orthophoto(*.tiff) of size 300Mb-2Gb. But this is taking 32s per request of lat-long, which is not ok. I have different Orthophotos with ...
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1answer
79 views

Centroid value extraction of Landsat image collection in Google Earth Engine

I have an NDVI collection wich I have created from the combination of different collections Landsat5 and 7. How can I exctract the NDVI values of the centroids of each pixel, of each image from my ...
2
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1answer
89 views

Calculate mean values for all bands and date to a dataframe

I have 5 rasters, each having 10 bands, where each band corresponds to a specific date. How do I calculate mean values for all 10 bands and save them? I need to save the mean values in a dataframe ...
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0answers
28 views

NDVI from SRGB image

I have a SRGB image from which I need to get the NDVI value. I know how to calculate the NDVI, but it does not work with this SRGB image.
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1answer
33 views

How to determine the average NDVI value of a selected area?

I'm new to ArcMap 10.2 and trying to get NDVI data of city centers. So my problem is, after I'm calculating the NDVI and getting the result raster, I would like to get a mean (average) value of ...
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1answer
62 views

Use Google Earth Engine to stack NDVI timeseries layers into one image and export

I would like to export the NDVI with the date in the filename in one image. Now I can only export them respectively. And when I export the NDVI image, it shows the error "Error: Exported bands must ...
3
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1answer
172 views

Treatment of Landsat 7 SLC error in Google Earth Engine?

Google Earth Engine distributes Landsat 7 image composites of indeces such as NDWI and NDVI that, when averaged on a shapefile, give back a coherent value. But how is SLC failure treated by it https:/...
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0answers
162 views

Nonlinear regression in Google Earth Engine on each pixel in an image collection using GEE's servers

I am attempting to optimize the parameters for a double-logistic function on an annual MODIS NDVI time series in Google Earth Engine. I have previously looked at Non Linear Regression in Google Earth ...
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1answer
91 views

Why does the raster calculator only give out 1 and 0 values

I have a problem with the raster calculator of ArcMap 10.5.1 because it only gives out a raster with 0 an 1 values. I'd like to calculate the Leaf Area Index out of a NDVI-Raster by using this ...
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1answer
87 views

Google Earth Engine equation for fractional vegetation using NDVI

I want to write an equation for fractional vegetation in Google Earth Engine using NDVI. My code is; var ndviClip = ndvi.clip(table); Map.addLayer(ndviClip, {min: -1, max: 1, palette: ['FF0000', '...