Questions tagged [ndvi]

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

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156 views

NDVI for orthoimagery in ArcGIS 10.3

I am working on orthoimagery which I got from drone (UAV). I am wondering if it is possible to create NDVI map from it. I was following the steps as described in this tutorial: NDVI in ArcGIS I ...
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1answer
464 views

How to calculate Percentages of NDVI Classes

I Have calculated the NDVI Using Landsat. I Classify it by threshold value of 0.25 I Then made 5 classes. Now i want to calculate the percentages of each class individually. please reckon me process.
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401 views

NDVI colour scheme for ArcGIS

Does anyone have a download link for the NDVI colour scheme to use in ArcGIS for Desktop? I am looking for MODIS mod13 data and cannot find an appropriate colour scheme in the programme.
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190 views

Obtaining NDVI data from red-edge imagery?

I am working with an aerial image containing three spectral bands (blue, green, and red-edge). I can obtain an NDVI image with the imagery using Erdas Imagine, but I do not know which bands Imagine is ...
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1answer
56 views

Extracting NDVI for large extensions using ArcGIS for Desktop?

I'm trying to calculate NDVI in ArcGIS for Desktop using MODIS to entire neotropical region but I can't find MODIS values for all neotropical. Instead, I foud only for small regions. Does someone ...
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95 views

NDVI for natural region

I have remote sensing data which I have got from landsat 7. The area which I am working on is combination of farms and natural area (Bare earth; without any vegetation). I want to estimate the ...
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1answer
639 views

How to conduct an NDVI and regression with ArcMap?

I would ideally like to execute an NDVI on a sample of NAIP images and then use the NDVI scores per district or whatever my aggregate zone is, probably census tract. My goal is to identify census ...
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2answers
1k views

Normalize the NDVI raster 0-255

NDVI values raster computed by using the band 3 and band 4 reflectance values b4-b3/b4+b3. The output raster is of 32bit type formate although the possible ranges that shows in statistics parameter ...
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1answer
89 views

Raster Calculator Blurring Image Results

I am trying to run a NDVI analysis using raster calculator on Arg Map 10.2.1 and the results create blurry or bleeding image, almost as if the map has been dipped in water. I am using the default ...
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1answer
222 views

how to multiply and group values of NDVI in Erdas

I have downloaded the MODIS data for calculating the NDVi but the ranges of values in its attribute table ranges from -32768 to 9830 i want to club the similar values upto 2 decimal places and also ...
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1answer
984 views

How to extract NDVI values into polygon vector map with QGIS

I have calculated the NDVI values of a satellite image using the raster calculator. Now I need to have these NDVI values extracted into the attribute table of my polygon vector file. Is there a plug-...
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11 views

MODIS DAAC2Disk fails with “Unable to obtain ECHO token”

I have been using the tool DAAC2Disk to easily download NDVI using an extent. However recently the tool fails with the error: "Unable to obtain ECHO token" Has anyone encountered such error? Or know ...
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3answers
52 views

Different NDVI in Python vs QGIS

When deriving NDVI out of a Sentinel-2 image - S2A_MSIL2A_20190502T074621_N0211_R135_T38SLF_20190502T102541 - I am getting a strange result when doing it in python vs in QGIS. In QGIS (using raster ...
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33 views

Chart - trendlines - slope - NDVI - visibleInLegend: true - GEE

I am using the following code in GEE to calculate the trend line: ndviChart.setOptions({ title: 'NDVI (Sentinel 2)', vAxis: {title: 'NDVI'}, trendlines: {type: 'exponential', 0: {color: '...
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1answer
33 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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21 views

Google Engine: Time Series Analysis with multiple point data [duplicate]

I have multiple points representing different crops for an area (say 100 per crop, and 5 types of crops). I compute the Sentinel2 NDVI for a period of one year. Even if I filter for just one type of ...
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1answer
42 views

Duplicate NDVI measurements on Graphs in Google Earth Engine

I have created the following code below for graphing the NDVI at areas of interest and printing it to the user interface. The problem I am having is that on the same date there are two different NDVI ...
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12 views

Rescaling NDVI from 0-255 to -1-1 in ArcGIS Pro?

My NDVI raster ranges from 0-255. My goal is to get values from -1 to 1. If using the Raster Calculator, what would be the correct equation to achieve this? I'm working in ArcGIS Pro.
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1answer
29 views

Format GeoJSON use Join method before export in Earth Engine

After filter an LANDSAT-05 for an small area var Collection = function(pixel) { var colForPixel = ee.ImageCollection('LANDSAT/LM05/C01/T1') .filterBounds(pixel) .filterMetadata('CLOUD_COVER','...
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1answer
100 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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1answer
51 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
44 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
58 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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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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134 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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42 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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21 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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0answers
103 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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37 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
147 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 ...
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32 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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89 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': ...
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1answer
361 views

Image Collection minimum and maximum Extraction in Google Earth Engine?

I've wrote this code but it makes error about min and max image? var modis = ee.ImageCollection("MODIS/006/MOD13Q1") .filterBounds(geometry) .filterDate("2000-01-01","2001-01-01") .select("NDVI"); ...
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1answer
121 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 ...
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1answer
120 views

Incorporating NDVI and texture metrics in OBIA-Supervised Image Classification

Anyone knows step-by-step tutorials for incorporating NDVI and texture metrics in land cover classification with ArcMap? I've been doing supervised classification of Sentinel-2 with the assistance ...
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42 views

How to find Dryest Pixel of an ImageCollection in Google Earth Engine? (Dryest pixel composite)

I want to create a composite with the dryes pixels of an ImageCollection. I know how to make a greenest pixel composite, but I have no clue how to make a dryest pixel composite. Is there a function ...
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92 views

Is it possible to create an average image of the analyzed period after the removal of the clouds to fill the flaws in the images?

// study area var local = ee.Geometry.Rectangle([-42.2974, -20.5299,-40.9406, -19.1815]); Map.addLayer(local); var landsat8 = ee.ImageCollection('LANDSAT/LC08/C01/T1_SR') // Fmask classification ...
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1answer
235 views

Removing Clouds From (Landsat8) NDVI Imagery with ArcMap? [duplicate]

I recently was able to generate NDVI images from Landsat 8 using Arcmap. My end goal is to run some zonal statistics over specific neighborhood polygons, however with the cloud values (ranges of 0.002&...
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284 views

Stretching (rescaling) Raster (NDVI) Values between -1 and 1?

I am trying to equalize NDVI values for the same area temporally. For example 2014 LS8 NDVI values between -.12 and .007 while 2011 LS5 values between -.33 and.77. I would like to equalize each raster ...
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1answer
66 views

AVHRR 1 km Coterminous US Server Location

I want to download a signficiant amount of AVHRR data directly from a FTP server... the problem is I'm having a really hard time finding the server location. I don't want to use EarthExplorer because ...
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2answers
458 views

QGIS NDVI Spatial Analysis

I have an NDVI raster that I would like to reclassify into some arbitrary bins i.e. all values between 0 - 0.2, 0.2 - 0.4 etc. for spatial analysis. Could anyone advise how to: 1) reclassify a ...
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0answers
808 views

Downloading NOAA AVHRR NDVI using R

I am using the gimms package to automatically download NDVI data from 1981-2013. The code is provided here. The data is available here. However, after running it shows that data has been downloaded ...
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0answers
488 views

Landsat 8 - NDVI Global Servises - Clouds

I'm looking for Landsat 8 NDVI Global Services, like ArcGIS Online, but including scenes with the high presence of clouds (50-95%). Fresh scenes with clouds needed because they can contain the areas ...
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1answer
321 views

Why do pixel (cell) values change for 32 real NDVI values when taking from Multispec to QGIS?

Landsat 5 values change from normal NDVI -1 to 1 when created in Multispec as a 32 bit signed data image. When adding the raster layer in QGIS, the value range changed to 0-255. How does one ...
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0answers
92 views

Looping over array of type float with interval of float (NDVI) using Python?

I am stuck with my Python Script. The case is, I have an array of floating numbers from 0 to 1 (NDVI values). I want to loop over my array with an interval/step of every 0.025. Every interval/step I ...
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2answers
162 views

AVHRR Max NDVI product

I'm trying to take a max annual NDVI product derived from AVHRR and relate it to a specific area that I'm examining.This requires me to identify the region of interest based on Landsat scenes, and ...
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4answers
131 views

Why does ASTER create -0 to 0 instead of -1 to 1? [closed]

On my previous question on ASTER I need some more information on ASTER for time series analysis and I need to research on building NDVI because when I ran them for each ASTER. Most of them it came out ...
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1answer
91 views

Creating composite band

I have land cover rasta data for the years 2000, 2010 and 2014. I would like to get the NDVI for each of the year. I have to generate the RGB first. I have tried the following things: 1. layer -> ...
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1answer
674 views

Analyzing stacked time series NDVI images in ENVI? [closed]

I just started playing around with stacking NDVI images from different years into one RGB value and am unsure how to read the photos or analyze them. The image on the left had R 2011 G 2011 and B ...
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1answer
1k views

Calculating average NDVI

I would like to calculate average NDVI values. I have 3 values of NDVI: high:243 low:0 high:243 low:0 high:238 low:0 How can I use a a raster calculator to calculate the average valvue