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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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1answer
17 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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0answers
29 views

NDVI out of range? [closed]

I calculate NDVI and it falls between +0.6 to _1.78. This was obtained after converting DN to Radiance and Radiance to reflectance for Landsat 7
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1answer
18 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
33 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
24 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
60 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 ...
1
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1answer
44 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
55 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
34 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
68 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....
1
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2answers
75 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
15 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
100 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
42 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
33 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
54 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 ...
1
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1answer
64 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 ...
2
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1answer
103 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: ...
1
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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 ...
1
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1answer
68 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 ...
1
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1answer
124 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
58 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 ...
2
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1answer
67 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 ...
3
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1answer
44 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
111 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
48 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
46 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
60 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 ...
3
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2answers
107 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
60 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
75 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
28 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
66 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
74 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
27 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
26 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
59 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 ...
4
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1answer
151 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
144 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
81 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
84 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', '...
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1answer
94 views

r.mapcalculator

I am using QGIS 2.18.25. I'm struggling to use r.mapcalc to calculate the ndvi for a workbook project. R.mapcalculator is shown on the workbook I'm using and seems simpler to use. Is there a plug-in ...
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2answers
176 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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0answers
56 views

NDVI Python image showing inverse

I am trying to calculate NDVI using python and landsat imagery. I am able to calculate ndvi using the following equation: def ndvi(sat, fp): raster = rasterio.open(fp) if sat.lower() == 'l8': ...
2
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1answer
277 views

Data smoothing of Sentinel-2 NDVI time series chart in Google Earth Engine?

I am exploring Sentinel-2 time-series NDVI with Google Earth Engine. In another post I learned how to plot a NDVI time series chart. I know that there are many smoothing methods for reducing NDVI ...
1
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1answer
305 views

Setting values for palette in Google Earth Engine

I am very new to GEE. I have been trying to figure out how to assign different colours to different NDVI values. Let's say, in following code, I want to assign 'red' for NDVI value of 0.2-0.4, 'orange'...
3
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1answer
232 views

NDVI Scaling in Google Earth Engine?

I am trying to download NDVI data from the Google Earth Engine MODIS satellite. I used the following dataset: img = ee.ImageCollection("MODIS/006/MOD13A2") To actually download it, I ran img....
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1answer
293 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 ...