Stack Exchange Network

Stack Exchange network consists of 175 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [ndvi]

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

1
vote
0answers
111 views

How to export polygon-wise average value of NDVI in Earth Engine? [closed]

I need the average NDVI value for some sample fields of a specific crop. I have the boundary polygons in a shapefile and imported it in the earth engine as fusion table. I have also calculated the ...
1
vote
1answer
88 views

Calculating Average NDVI value for research Plot?

I am working on a Field trial with small research plots. I've created a GeoTiff orthomosaic with 4 bands from a multispectral camera (Red, Green, NIR, Red Edge) and want to be able to extract the mean ...
1
vote
1answer
99 views

Create a grid of NDVI maps from different dates

I want to create a grid of 4 NDVI maps from different dates with the same parameters so I can check variance over a period I tried to change an example named 'Linked Maps' in User Interface folder in ...
2
votes
1answer
99 views

Aggregating/Averaging NDVI across pixels. Arithmetic mean seems bad choice

I need to compute an aggregate index for vegetation density in certain (large) shapes, to assess desertification. I have NDVI data at a high spatial resolution (~100 NDVI-pixels per aggregation shape, ...
1
vote
2answers
147 views

Classification model using NDVI time series?

I am trying to form a classification model with the help of NDVI time series data. I want to use methods like SVM and Random Forest. I know how to apply these methods to normal data. But, I am ...
3
votes
2answers
508 views

Maximum ndvi for 3 months average in Google Earth Engine

I have a ndvi series which I am able to plot using below code: var ndvi = l8.map(function(image) { return image.select().addBands(image.normalizedDifference(['B5', 'B4'])); }); var ndviChart = ui....
1
vote
0answers
114 views

How can I fill NA values in my NDVI Data? [closed]

I have been trying for weeks now to clean my NDVI data. I know that I have to apply Savitzky-Golay filter to smoothen my data. But before that, I have to fill the missing values in my data. I am ...
1
vote
1answer
38 views

Calculate Values from a raster surrounding a list of addresses

I have a list of addresses and I have geocoded into a shapefile in ArcMap 10.4. I've also made a raster that stores NDVI data (with water masked out as it will skew the values we are hoping to obtain ...
0
votes
1answer
296 views

Change pixel size of MODIS in GEE

I am trying to perform some scale-tests with some data on GEE. I have the following code where I use the MODIS-NDVI dataset at 500m. What I want to do, is to perform the same analysis but on 25000m x ...
0
votes
2answers
217 views

how to loop ndvi using R in sentinel-2

I have a two different stacks: one for band 4 (RED) and other with band 8 (NIR). I'm trying to loop the calculation of NDVI in an area of interest using R. Well, this is the loop that I'm trying to ...
1
vote
0answers
41 views

How to Substract one image band from the subsequent in Google Earth Engine?

i am trying to find the day of year (doy) for each year with the highest change in NDVI compared to the day before, to map in the end a shift in start of season. My code to seperate each year so far (...
0
votes
1answer
292 views

Filling gaps in NDVI time series? [closed]

I'm something of a beginner to remote sensing. I've got an NDVI time series, from 2002-2016. I've smoothed the data using an excel spreadsheet with the formula yt = (-2xt-3 + 3xt-2 + 6xt-1 + 7xt + ...
2
votes
1answer
280 views

Troubleshooting downloading MODIS NDVI Data in R

I am trying to download MODIS Data from 2000-2018, however I am encountering some difficulties. Here is my script MODISoptions(localArcPath = "/Volumes/myserver/MODIS/data", ...
1
vote
1answer
84 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 ...
3
votes
1answer
191 views

Applying NDVI formula with PyQGIS on multiple rasters in the Layers Panel

I'm trying to write a Python script in QGIS using the Python console that applies the NDVI formula to all rasters in the Layers Panel, and outputs a new NDVI raster for each original raster. My skill ...
1
vote
1answer
570 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:...
1
vote
0answers
2k views

Using Python with Google Earth Engine?

I'm trying to replicate this python script to calculate NDVI mean for a feature collection (https://stackoverflow.com/questions/47633088/get-results-in-an-earth-engine-python-script). It seems like ...
1
vote
3answers
261 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 ...
6
votes
1answer
206 views

Which NIR bandwidth is suitable to Calculate NDVI?

Often we encounter multi-spectral and hyper-spectral sensors offering multiple NIR bands. For instance, the WorldView 3 sensor has 8 MS bands, out of them, two bands fall within NIR region. Near-IR1: ...
2
votes
2answers
3k views

Writing code for monthly NDVI medians in Google Earth Engine?

My goal is to get monthly NDVI medians in Google Earth Engine. This helpful post got me started: reduce image collection to get annual monthly sum precipitation However, I am using Landsat (not MODIS)...
3
votes
1answer
450 views

NDVI-time series with missing values

I have a Landsat-NDVI-time series from 2013 - 2017 with 23 observations per year (115 scenes in total). My goal is to get a smooth time series for a selected single pixel (maybe by using a Savitzky-...
-1
votes
1answer
372 views

Performing Cokriging in R? [closed]

I would like to perform cokriging of 60 observed data points. In the shapefile, there are 60 fields containing the observations as Time 1 to Time 60. I also have 60 rasters in tiff format. I want to ...
3
votes
1answer
574 views

How to enforce float values for NDVI in ArcGIS?

I am trying to calculate NDVI from Landsat 4-5 TM imagery (of the year 2008) using the formula NDVI = (band4-band3)/(band4+band3) from Raster Calculator of ArcGIS 10.4.1. The problem that I am facing ...
2
votes
0answers
187 views

NDVI calculation problem

I have photo created by UAV, and I want to calculate bNDVI: (NIR-blue)/(NIR+blue) I have these bands (filter is ok -100%). So using QGIS I have values -0,1-> 0,3 - but bNDVI must be from 0,65->0,...
0
votes
1answer
157 views

Seasonal analysis in Google Earth Engine

I want to perform a seasonal analysis of the MODIS NDVI dataset in GEE. I want to analyse for every year the months from May to September and thus, I need to remove the rest of the months from the ...
1
vote
1answer
102 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 ...
1
vote
1answer
234 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'); ...
1
vote
0answers
98 views

rescale MODIS NDVI value- fill value and background value after clip study area

I want to use MODIS NDVI time series to extract phenological parameters using TIMESAT software. I have question about data prepration, Is it alwaysd necessery to rescale NDVI data? valid range in ...
1
vote
1answer
276 views

LinearRegression with Google Earth Engine

I ve been doing simple linear regressions with GEE and I have found a possible error that I would like to share and in case that I am wrong, please let me know: Is it possible that when ...
1
vote
0answers
117 views

masking in ENVI [closed]

I have surface reflectance generated NDVI which I got from ESPA interface, https://espa.cr.usgs.gov. How do I mask cloud with Qa band in ENVI?
3
votes
2answers
100 views

Vegetation Index for dry and sparse vegetated areas?

I found many different index for the estimation of vegetation cover, but many of them struggle in sparse areas with low vegetation cover, as the soil signals are way stronger than the vegetation ...
-2
votes
1answer
178 views

Looping for NDVI in different file paths using R? [closed]

I have different bands separated in different file directory. I used Raster Calculator to calculate NDVI using "NIR1.tif"-"RED1.tif"/"NIR1.tif"+"RED1.tif" as formula. The link below describes a loop ...
1
vote
1answer
271 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 ...
2
votes
0answers
121 views

EVI2 values dont' come out -1 to 1? [closed]

I'm very new to remote sensing in general, and aren't sure if I've made an error. I've calculated EVI2 for a Landsat 8 and Sentinel 2 image. Both Top of Atmosphere. I've used Google Earth Engine to ...
0
votes
0answers
89 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 ...
1
vote
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. ...
3
votes
0answers
170 views

What bin value does QGis Histogram uses?

I have some single-band rasters (NDVI) on Qgis, for which I can obtain their distribution histogram by going to Right-click > Properties > Histogram Tab > Compute Histogram. This is an ...
4
votes
1answer
332 views

Black vertical lines on exported image from Google Earth Engine

I tried to export the NDVI obtained from the Landsat 8 Surface Reflectance Collection in Google Earth Engine and I keep on getting black lines in my final export. Everything looks fine when displaying ...
0
votes
1answer
95 views

interpreting Normalized Differentiated Bareness Index and Normalized Differentiated Impervious Surfaces Index? [closed]

I've tried looking for various sources to help me interpret NDBaI and NDISI indices but I've not found anything particularly helpful. Does anyone know how to do it or have any literature that might ...
2
votes
2answers
47 views

NDVI image contains 500 cells or more using ArcMap

I want to make a map that shows my NDVI image (with 6 classess, natural breaks that I reclassified already)) that only contains zones with 500 cells or more and that are color coded to the area of ...
2
votes
3answers
210 views

Loop using variable - r.mapcalc GRASS GIS

I am doing threshold classification of NDVI rasters. One equation looks like that: r.mapcalc 'prog_r43_n65=if(ndvi_r43_n65>=0.6,1,2)' Now I want to make a loop for more than 2000 rasters, so I ...
1
vote
1answer
248 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: //...
0
votes
1answer
195 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&...
3
votes
0answers
455 views

Difference between gdal_calc and QGIS raster calculator

I am hoping someone can help me with an issue I am having with gdal_calc. I am looking to create NDVI rasters from 4 band 8 bit ortho tiles. I have processed the tiles using the following calculation: ...
0
votes
2answers
2k views

Export time-series MODIS 16 Day NDVI and EVI Data on Google Earth Engine [duplicate]

I want to extract every single MODIS 16 Day NDVI and EVI Data image on a particular area from 2000 to 2016. I was able to filter image collection but I do not know how to export every single image on ...
1
vote
1answer
188 views

ModisDownload - doubts when using MRT tool

I am using the incredible MODISDownload function from the rts package in R to download NDVI data on vegetation index in Africa. I have two questions. I am using the latest version of the package ...
2
votes
1answer
105 views

Exporting NDVI as .TIF using ArcPy?

Here is my code so far: import arcpy from arcpy.sa import * arcpy.CheckOutExtension("Spatial") workspace = arcpy.env.workspace = "C:/Users/KJanus/Desktop/Intro_ArcGIS/RasterData_Lab6" arcpy....
1
vote
1answer
551 views

Monthly GIMMS NDVI time series

I need to create a monthly NDVI time series from GIMMS in GEE (i.e. from January 1981 to December 2013) from the sum of fortnight values (or mean). I've been trying to create a function to do so, but ...
0
votes
1answer
396 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 dont know the steps to ...
1
vote
2answers
542 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 ...