Questions tagged [ndvi]

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

78 questions with no upvoted or accepted answers
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775 views

Landsat level-2 data comparison

I'm doing a temporal analysis of NDVI and temperature over 17 years, necessitating data from Landsat 5,7, & 8. I'm interested in using level-2 Landsat data available from https://espa.cr.usgs.gov/...
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275 views

QgsRasterFileWriter.writeRaster() is crashing python program

I am doing ndvi analysis on a farm image. After ndvi I need to convert the image into Singleband pseudocolor image using following python code. def calculate(): file_name = CUR_DIR + "\...
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0answers
186 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 ...
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515 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: ...
2
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0answers
25 views

Finding whether a particular band value is consistently less over a period of time in an image collection

The code below gives me forest regions of India from the Hansen data set and then I have filtered the landsat images of these regions from 2013-2019 on a quarterly basis. My output image is such that ...
2
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1answer
111 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 ...
2
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0answers
214 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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0answers
128 views

Calculating indices such as NDVI or NDSI on Landsat 8 imagery whose pixel type is 16 bit signed integer?

I am trying to calculate an NDSI (Normalized Difference Snow Index) using Landsat 8 OLI level 1 imagery atmospherically corrected in ERDAS ATCOR using raster calculator in ArcMap. NDSI is used to to ...
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0answers
214 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,...
2
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1answer
143 views

Which output data type to choose in QGIS SAGA Raster Calculator in Batch Mode?

I have 5 years of MODIS13Q1 NDVI .tiff images for time series analysis. I want to multiply all the images with the scale factor of 0.0001 before using them. In order to process all at once I try to ...
2
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0answers
73 views

Overlaying point data with NDVI layer with raster output (not graph)

I have point data, which are animal burrows, and a NDVI raster layer that shows plant productivity. I want to overlay these layers and determine if vegetation productivity is higher close to burrows (...
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232 views

Supervised Classification Plugin QGIS: change input image; use another raster layer

I'm doing supervised classification on a sugar cane field for identifying vegetation, soil, and soil and litter. The plugin is only taking in the GeoTiff taken from the multispectral camera we used (...
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514 views

Pixel based Regression

I have 80 .tif files, and each pixel value represents NDVI. The whole stack of images is a time-series. I want to run a regression for each pixel using NDVI and time. I have tried to approach this ...
2
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0answers
78 views

Extract Mean Raster Value from multiple raster files into Excel

I have a series of non-orthorectified raster files containing NDVI information. I would like to extract the mean value from each raster so I can see a summary of each raster image name and the ...
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0answers
193 views

16-day-MODIS NDVI values seem to be wrong compared to my soil moisture ground data!

I'm using MOD13Q1 product of MODIS for estimation soil moisture. As I know, this product is made up of the maximum value of NDVI of each pixel over 16-day calculated NDVI values. The problem is that ...
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0answers
400 views

QGIS 2.4.0-Chugiak: How to produce raster colour map

By carefully deriving the NDVI values from Landsat Band 3 and Band 4 after doing atmospheric correction by applying DOS1 method in semi-automatic classification Plugin QGIS, I was to calculate the ...
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0answers
248 views

Comparing/Correlating NDVI Rasters with other index Raster

So, I've created two rasters. One for NDVI and one for another index for surface water from the same orthorectified World-View 2 image. I can visually see how the indexes are inversely proportional. ...
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0answers
2k views

Interpreting NDVI value on water?

There is a surreal thing on my NDVI images. NDVI values on lake is ranging from -0.04 to 0.7. (The lake surrounded by forest and has freshwater). Theoretically, negative value of NDVI is correspond to ...
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14 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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16 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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25 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
46 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
29 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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73 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
82 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
96 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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0answers
41 views

Error in smoothing NDVI (BISE) using SPIRITS

I want to minimize the spikes caused by cloud cover (smooth) NDVI timeseries data before applying Savitzky–Golay filter in Timesat. My previous post was also related to timeseries (Interpreting NDVI ...
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0answers
13 views

Does Modis offer MultiYear statistics?

I'm trying to calculate the VCI data for my entire State. I'm using MODIS's 16 day NDVI Average. From this post, I see that I would need to calculate the Min & Max NDVI values for each pixel ...
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0answers
444 views

Writing numpy array to rasterio raster file generates empty file

I'm using Rasterio to read GeoTIFF from Sentinel 2 and calculating NDVI, but when I try to save as a new TIF file, the file turns to transparent and empty file. What am I missing? That's the code: ...
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0answers
126 views

Dimensions of images given their latitude and longitude for Google Earth Engine

From the point long: 16.499050771335575, lat: -30.882 I want to find the corresponding latitude and longitude values that would result in a 200 km by 200 km square in which the aforementioned ...
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0answers
59 views

Using Band Math in R Creates Raster with Different Coordinate System?

I am trying to make a simple NDVI raster from a Landsat 8 image (containing bands 2-7). The Landsat image has a Coordinate System of NAD_1983_UTM_Zone_11N (and datum: D_North_American_1983). When I ...
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0answers
601 views

Creating a area time series chart on Google Earth Engine

I'm using Google Earth Engine for a article on my university, and I wanna get the evolution of water area of an water body of my region. For that, I'm using NDVI on time series on GEE. I got the NDVI ...
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0answers
234 views

How to preprocess and remove noisy data from Landsat-8 image Bands for ndvi time-series analysis

I'm working on satellite image processing, I'm calculating NDVI for time series analysis and vegetation prediction. I'm having a tough time removing the noisy data like, Cloud coverage Haze Cloud ...
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0answers
146 views

NDVI raster to polygon in QGIS

I have an NDVI raster created through a Parrot sequoia and Pix4D. When imported into QGIS 3.0.2 it is shown as a singleband gray render type with a range of -0.355826 to 0.905562. I want to create ...
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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 (...
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1answer
86 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 ...
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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 ...
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0answers
115 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 ...
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0answers
193 views

Opening ENVI files in ArcMap?

I have calculated NDVI (vegetation index) in ENVI 5.2 and I saved it in TIFF format. Now I am trying to open it in ArcMap, but its not opening properly. The image is total black and the values are ...
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0answers
517 views

How to export image on google earth engine for large area?

The area that i have been work have about 159695,938 km² and I am mapping the deforestion on this with NDVI. I had to use 2 years to remove all the clouds (eg. 2015-01-31 , 2016-12-31) using a reducer....
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0answers
48 views

What is the best way NDVI can be used for assessment of remediation level of ecosystem (after nuclear accident)?

I am thinking about ways to assess efficiency of various bioremediation methodologies and self-remediation of an ecosystem polluted with nuclear waste. I would like to use NDVI as an assessment ...
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0answers
41 views

Sudden errors intersecting NDVI raster data with overlapping polygons in GME

I am experiencing errors with Geospatial Modeling Environment (GME) that suddenly developed after things were working perfectly. Description of software installed: ArcGIS 10.3.1 for Desktop and ...
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0answers
140 views

How to display data within a drawn polygon

I am using mapbox as my base layer and would like to implement a functionality as shown in this gif below, where if i draw a polygon , it reads from my geotiff file and display NDVI data. I would like ...
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0answers
382 views

Unable to retrieve NDVI coloured images to local storage using Google Earth Engine API

I am currently developing an application which requires LANDSAT NDVI coloured images to be retrieved to local storage. to carry out the task i wrote a script in python using earth engine API (source ...
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0answers
30 views

What indices could is use for coastline extraction using rapideye imagery

I am currently writing a proposal to get RapidEye imagery for my master thesis. In this proposal I am trying to explain what I am doing. Except NDVI/NDVI-RedEdge and NDWI, can anyone suggest some ...
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0answers
194 views

Why are Landsat-8 derived NDVI values higher than SAVI values?

I have calculated NDVI and SAVI vegetation indices for a landsat-8 image. I am unexpectedly getting higher values for the NDVI than SAVI. What may be causing these unusual results? NDVI=0.46 SAVI=0....
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0answers
140 views

Radiometric calibration NDVI values in Excel

I´m doing NDVI analysis, but i forgot to do Radiometric calibrations in QGIS. So the NDVI values in my excel table are in DNs. Can I do this calibration directly in excel?
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0answers
1k views

Histogram matching of two NDVI images

I have two Landsat 5 NDVI images (Surface Reflectance products) from the same period of the year (only a few days apart), but one is from the 1980s and one from the 2000s. I am trying to do a change ...
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0answers
74 views

How to create a map showing NDVI result in erdas?

I'm using Spot 5 image to run an NDVI analysis. The band that I used in processing is 4,3,2. The area was 80% covered by mangrove. My problem here how can I create a map to show or present the result? ...
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0answers
79 views

Using NDVI values as covariate in survival analyses

I am trying to become more familiar with processing NDVI values in GIS. However, despite its usefulness, it seems to have some limitations. Namely, creating NDVI values across a large scale can be ...