Questions tagged [ndvi]

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

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68 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 ...
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29 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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161 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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100 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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226 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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1answer
53 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
101 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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1answer
643 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'...
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521 views

Google Earth Engine API: How to select an image from an image collection based on NDVI value?

I want to select the image with lowest median NDVI to represent bare ground cover from Sentinel-2 image collection for my region of interest (<5% cloud). I have a boundary file pre-loaded on ...
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1answer
42 views

NDVI values to image conversion

I have a column of NDVI values of several centroid of pixels and relevant longitude/latitude associated with it. I want to convert this table to a raster image in ArcGIS 10.4.1. I know the conversion ...
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69 views

Identifying high NDVI values close to vector lines

I have NDVI raster data and vector line data for the St George Queensland irrigation channels. I am trying to detect irrigation channel leakage using high NDVI values detected on the immediate bank....
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98 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 ...
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1answer
131 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 ...
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1answer
40 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 ...
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1answer
368 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 ...
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1answer
232 views

identification of Forest cover area by using eCognition Software

How to find forest cover area by using eCognition software? I'm trying to find vegetation by using NDVI in the ruleset but it takes vegetation too with the forest. Can I use any other filter along ...
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1answer
248 views

How to convert NoData values to other values for raster data?

I have a NDVI map from MODIS data for my AOI. When classified, i noticed that few of the pixels appear in " white" color and show no value. How do i classify these pixels and attache an appropriate / ...
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1answer
760 views

Image segmentation

I am performing a segmentation on an NDVI using the OTB mean shift segmentation on QGIS 2.18. The size of the image is about 15000*15000 with one band only and 8-bit. Since I do not want to use ...
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1answer
770 views

multiply range of value NDVI of Modis product in Google Earth Engine

Modis product have range of value NDVI from -2000 to 10000, but I need this range of value modify on range from -0,2 to 1 This is my code for finding NDVI in region: var California = ee.Feature( //...
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1answer
540 views

How to remove cloudy pixel from MODIS NDVI (MOD13Q1)

I am using MODIS NDVI product (MOD13Q1) for the vegetation changes study. I want to remove cloudy or bad pixel from MODIS NDVI data. I am not getting any suitable method or software or any program to ...
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2answers
929 views

How to define season by month and average data

I have 10 year NDVI data i.e. two values per month. I would like to average values within a season e.g Season A (January, February and March) per year and plot a graph. y axis=average ndvi value, x ...
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1answer
240 views

Pixel based 10 year NDVI time series

I would to do pixel based 10 year NDVI time series analysis using MODIS data. I’ve 3 seasons in a year. Should I average all values in the study area per season?
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319 views

time-series analysis

I have 46 MODIS NBAR images of the same area (time-series). How can I get seven (1 for each band) multilayer (46 layer) images, for the further FastICA analysis? According to the results of the paper, ...
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1answer
971 views

NDVI values for MODIS images [duplicate]

I have downloaded NDVI MODIS 500m image i.e. MOD13A1. From the hdf format that i got i converted them into tif format using the HEG tool. The images that i got some are showing pixel values -32767 to ...
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1answer
186 views

how to calculate the ndvi % greater than 0.5 in a particular zone and also cloud percentage

i have a problem whem i am working to calculate the ndvi from landsat sattellite of rainy season i have assumed the pixel value above 15000 are clouds and calculate NDVI.then i am assigning the clouds ...
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1answer
289 views

NDVI error in ERDAS

I have created a NDVI image from Landsat 7 data using ERDAS (veg_NDVI.gmd). This model was already in ERDAS 9.3. After creation the final output visually highlighting vegetative areas but the value ...
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1answer
548 views

Doing NDVI when nir data is given as 3 bands

I have been provided with two data sets of the same area, one with normal RGB bands and one with NIR data. My problem is that since the NIR data is given as 3 bands, i am not sure how I should ...
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1answer
77 views

Long term NDVI mean from different resolution satellite imageries

I have 10 years satellite imageries of different resolution (Landsat TM, LISS3, AWiFS and Landsat 8). My aim is to generate long term mean NDVI from that data. Since the resolutions are not same, i ...
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1answer
251 views

Apply regression equation to Landsat ETM+ image

I have sample points in an Excel file with XY coordinates and canopy density. I also have a Landsat ETM+ image. All points are collected from the same area as in the image. I exported all sample ...
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1answer
314 views

Canopy density & NDVI Regression using ArcGIS for Desktop?

I have a Landsat ETM+ image, I also have 200 sample points with coordinates,canopy density, different band values and NDVI values. If I build OLS model I only got sample points regressed. How can I ...
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1answer
1k views

How to calculate area of respective pixel?

I wants to create NDVI Map, In which it shows an area of respected pixel value lies in map.I have NDVI value within -0.6 to 0.7. Suppose,I wants to calculate area of 0.5 NDVI value with scale of map....
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1answer
864 views

how to calculate area verses each NDVI value?

I created an NDVI map, I want to calculate area of vegetation verses the respective NDVI value of the given map. Which tools are used for this process and what steps are required?
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1answer
457 views

create a vegetation mask using Landsat 7 [closed]

I'm working on a very large study area. The aim is to create a vegetation mask representing only pines. I'm using Landsat 7 images. Since the recordings were made in the winter it's pretty easy to ...
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1answer
544 views

Creating Time-series (Temporal) Map of NDVI?

Is there a best practice for a cartographer to create a Time-series or Temporal Map ? I have 83 of the NDVI in an imagine format and should I converted them to polygons and populated them and display ...
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1answer
5k views

How to get percentage coverage of raster values in an overlapping polygon?

I have an NDVI image in ArcGIS 10.1 which is from -1 to 1. I have reclassified that image in 0 (range all negative value - non-green) and 1 (all positive value - green). I have overlayed a 'fishnet' (...
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1answer
122 views

Sources for long-term NDVI datasets with coverage to west Asia?

I'm in need for long-term NDVI dataset for my research in bio-climatology, looks like GLCF GIMMS are no longer available online, any suggestions/workarounds to get the data.
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948 views

How to get “p value” for time series data to detect significant change

I have yearly maximum NDVI data (1982-2008) and extracted all value to Excel. Also calculated slope value for each point during the 27 years. All of you know the slope value represents changes per ...
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1answer
2k views

Removing pixel values below -1 using ENVI?

I have downloaded NDVI from MODIS website and pixel values go up to -3000 to 1. I want to remove all values below -1. How do I do this? I am using ENVI 4.3
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12 views

Calculate the annual mean NDVI for a region using the Maximum Value Composite

I first used the Maximum Value Composite to generate a annual NDVI for a watershed, and then calculated the mena NDVI for the entire basin. I don't know if this code is correct. In addition, I want ...
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0answers
24 views

Comparing NDWI regions with a given shapefile Google Earth Engine Python?

With the code below, I computed the NDVI, NDWI and NDWIMOD indices of a R.O.I. in order to detect water areas in that R.O.I. Now, my goal concerns to compare the water areas with a given shapefile ...
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0answers
13 views

Problem merging/clipping MODIS rasters in QGIS

Im pretty new to QGIS and am having some trouble making a NDVI map for Mali. To cover the whole country I need 5 MODIS NDVI tiles, however every time I try to merge them I get a "the following layers ...
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16 views

I am trying to create an NDVI image using an RSGISLib python script, but it is displaying no data values

My script runs fine and creates an output, but the output is displaying values all the way down to -999, rather than just having the values present in the NDVI result (0-1). I can create an NDVI image ...
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0answers
17 views

Scaling factor for MODIS (MY09GA 006 or MYDTBGA 006) product for timeseries data

I was using Modis data (MYDO9GA) product for my research and I was following this document as a user guide. https://landweb.modaps.eosdis.nasa.gov/QA_WWW/forPage/user_guide/MOD09_UserGuide_v1.4.pdf ...
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0answers
30 views

Calculating NDVI values for specific zones using zonal statistics using QGIS

I am currently working with multispectral data from a MicaSense RedEdge M on a plot size study in wheat research plots. I want to conduct zonal statistics to calculate NDVI for individual plots. I ...
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1answer
51 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
34 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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82 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
403 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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1answer
99 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
108 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 ...