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
801 views

Performing per-pixel linear regression over multiple rasters with NoData?

I have a stack of 10 Landsat satellite images over the same area that I have calculated NDVI for. I want to calculate NDVI trend over time on a per-pixel basis. This means that for each pixel in the ...
3
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1answer
524 views

Better NDVI for Landsat 8?

I'm looking at NDVI changes for an area over 20 years. There seems to be a slight downward trend, however, upon switching from Landsat 5 in 2011 to Landsat 8 in 2013 I'm getting NDVI values that are ...
3
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1answer
1k views

Pixel-wize trend analysis of an irregular time series stack of NDVI rasters in R

I'm interested in doing a pixel-wize trend analysis of a series of NDVI images from Landsat in R. The problem is that my images are not exactly happening at regular intervals. But decent imagery of ...
3
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1answer
167 views

How to represent seasonal variability in a single global NDVI map?

I have twelve monthly MODIS datasets for a 1 year period (http://neo.sci.gsfc.nasa.gov/view.php?datasetId=MOD13A2_M_NDVI&year=2015) and wish to combine all the data into a single map highlighting ...
3
votes
1answer
439 views

QGIS raster calculator: difference gives NaN for Landsat 8 scene

I'm strugling with the QGIS Raster Calculator, trying to get a NDVI image from a Landsat 8 scene (path 222, row 84, date 2015-11-15). The problem is, I'm consistently getting NaN values for all the ...
3
votes
1answer
328 views

Extracting NDVI using QGIS from multiple images to Excel?

I created 25 images in QGIS. Each image has different information about the NDVI of the area. How can I extract mean, max, and min information about the NDVI from each image and put it in Excel?
3
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1answer
85 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 ...
3
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1answer
50 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 ...
3
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1answer
348 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....
3
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1answer
297 views

Determining the best month for discriminating between different vegetation types?

I ordered and downloaded several (Surface Reflectance) Landsat 5-8 images from USGS Earth Explorer with the purpose of choosing a few of them to calculate some Vegetation Indices for each (NDVI, SAVI, ...
3
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1answer
2k views

NDVI time series in R — how do I create a time series object from a data frame?

I am doing a time series analysis of NDVI using the bfast package in R. Bfast requires a time series (TS) object. I have successfully created a data frame with the NDVI at various point locations ...
3
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2answers
651 views

SPOT NDVI time series

I have 423 spot.vgt ndvi from first April 1998 till 31 Dec 2009. I want to know how to stack these NDVI to have one image for time series analysis? Or better to ask how is it possible to analyze a ...
3
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2answers
224 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 ...
3
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2answers
97 views

Computing NDVI in ArcMap from Landsat 8 “Analysis-Ready” Surface and TOA Reflectance Products

The internet is full of various contradictory advice on corrections one can make to get NDVI computed from Landsat 8 to fall between -1 and 1. This is for instructional purposes, so I hope to use ...
3
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1answer
243 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 ...
3
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2answers
105 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 ...
3
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1answer
172 views

How can we calculate the area of dense and sparse vegetation from NDVI image in QGIS?

I'm trying to obtain values of area covered by dense and sparse vegetation through NDVI classification. I'm using QGIS (2.18), ERDAS 2014 and ArcMap.
3
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1answer
2k views

Unable to create NDVI image using Python gdal package

I have Python 3 and all GDAL bindings installed on my Windows machine, so that when I run this: import numpy as np from sys import argv from osgeo import gdal, gdalconst I get no error messages. ...
3
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1answer
832 views

NDVI image processing

I am trying to get a NDVI image from an RGB + NIR image captured by a modified Cannon S110 camera bought from Event38 along with a 3DR Iris+ drone link The image captured with the camera looks like ...
3
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1answer
196 views

Temporal spectral analysis in order to differentiate agricultural/croplands from natural/semi-natural grasslands using remotely sensed data

I am working on a critically endangered bustard species in India (Houbaropsis bengalensis). I need to prepare a land cover map of its 'suitable' grassland habitat across its distributional range. I ...
3
votes
1answer
1k views

Converting Worldview 2 imagery to TOA reflectance for Vegetation Change detection in ArcGIS?

I am working on a change detection study to look at effects of herbicides on vegetation growth. Therefore I have Worldview 2 (4 band +pan band) imagery for two subsequent years that I would like to ...
3
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1answer
825 views

Applying savitzky golay filter to MODIS NDVI data

I want to smooth the NDVI MODIS 16 bit integer data .tif for LULC classification. I have timesat 3.1 software on windows but I don't how to apply the SG filter. I am not that good in programming. I ...
3
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0answers
188 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 ...
3
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0answers
527 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: ...
3
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2answers
1k views

NDVI analysis of LANDSAT 8 imagery in QGIS

I am trying to run an NDVI classification of 2015 multispectral LT8 imagery in QGIS to assess the quality of vegetation cover in regards to habitat suitability for a primate species in northern ...
3
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0answers
699 views

How to create an annual NDVI from Landsat 8 imagery [closed]

I am relatively new to GIS. I am studying wildlife (I have collar data that lasts a year) and my supervisor and I would like to create an annual NDVI map for my projected area. I was able to ...
3
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0answers
37 views

Creating coloured map from Excel using ArcGIS for Desktop? [duplicate]

I have an Excel file with some data and I want to create a map and present data with colours. I do everything well except for I present my data with dots. Instead, I need to cover the free space with ...
3
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0answers
109 views

VI Quality dataset in MODIS image [closed]

While importing NDVI dataset in ArcGIS should we also import the VI_Quality dataset ? If yes then how should we handle it ? and, if not, then for what it is there ?
3
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2answers
2k views

Calculating NDVI using Landsat ETM+ band values

I have sample points (shape file converted from a .xls file which contains XY coordinates,nnx,nny and canopy density) and a landsat etm+ image. First I applied 'SpatialAnalyst Tools>Extraction >Sample'...
3
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3answers
2k views

NDVI image value changes from -1 to 1 in ENVI to 0-255 in ArcGIS Desktop and ERDAS Imagine?

When i open NDVI image in ENVI, its value is still within the range (-1 to 1). But when I open this NDVI image in ERDAS and ArcGIS Desktop, its value is 0-255. What does it mean? Is the NDVI ...
2
votes
3answers
1k views

Where to obtain free 15m ASTER image for New Mexico?

I am looking for a free Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) image that will let me to perform NDVI for the pilot crop health/soil moisture that can go as far back ...
2
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2answers
16k views

Using Raster Calculator to generate a NDVI in QGIS [closed]

How can i access raster calculator (to generate NDVI) in QGIS? In case this is not a recommended method, is there any other way to generate NDVI in QGIS?
2
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2answers
1k views

Calculate NDVI using ArcPy Spatial Analyst

My goal is to calculate NDVI using map algebra syntax. import arcpy from arcpy.sa import * red_band_raster = (r"C:\B3.tif") nir_band_raster = (r"C:\B4.tif") #Calculating NDVI float raster ...
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)...
2
votes
1answer
2k views

Tutorial Vegetation Condition Index

Anybody here can help me regarding calculating Vegetation Condition Index (Kogan,2004) for Landsat?. Specially facing problem in NDVI_max and NDVI_min; which should be maximum and minimum value?
2
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1answer
2k views

Using Loop for calculating NDVI in R?

I am using MOD09Q1 now and I would like to calculating NDVI whole year data. One year, I have 46 band 1 images and 46 band 2 images. list.files I creating list of band 1 and list of band 2. ...
2
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1answer
2k views

How to create NDVI map From LiDAR intensity and RGB image

I am new with GIS and I've been looking for ways on how I could create a NDVI map from LiDAR intensity and RGB image. Is there any way I could do this? I have read that you could create an intensity ...
2
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3answers
228 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 ...
2
votes
2answers
574 views

NDVI from Landsat8 LandsatLook images

I have downloaded landsat image from this site and now Im wondering if i can get NDVI index from it. In raster calculator I have only 3 ranges, shouldnt be four? Or am I doing something wrong? If ...
2
votes
1answer
111 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....
2
votes
1answer
168 views

Make raster layer in ArcPy?

I am trying to calculate NDVI from rasters that I've downloaded with download rasters, clipping them with some features (selection_feature) that I'd split from an original archive. I am a begginer in ...
2
votes
3answers
234 views

MODIS temperature and NDVI data?

hope anyone could give me some hints here. I tried to download free MODIS data from their page(resolution 500m, 1km). Im interested in NDVI and temperature data. But when i load the hdf files into my ...
2
votes
1answer
1k views

ListRasters based on filename using Arcpy

I am trying to create a python script for ArcMap which calculates the ndvi from two raster images for each RGB/NIR pair in a folder. However, I am unsure how to create two raster lists; one which ...
2
votes
1answer
445 views

Using ASTER for time series analysis?

This is a follow up to Where to obtain free 15m ASTER image for New Mexico?. If I want to analyze 10 years or so, do I need to download each ASTER file for each year (e.g. 2003 ASTER, 2004 ASTER,...)...
2
votes
1answer
438 views

Right raster zonal statistics for NDVI at county scale?

I am currently doing a modeling project at county scale in which I have disease rate as dependent variable and environment variables (such as temperature, NDVI and evapo-transpiration) as the ...
2
votes
1answer
124 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 ...
2
votes
1answer
181 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 ...
2
votes
1answer
1k views

Calculating NDVI per region, month & year with Google Earth Engine?

I want to calculate the mean NDVI per region (admin level 3, also called woreda), month and year. So my end result would look something like this: regions year month NDVI ------------------...
2
votes
1answer
249 views

Image Collection Statistics in Google Earth Engine?

How can I extarct mean of each image collection in google earth engine? for example for this code: var modis = ee.ImageCollection("MODIS/006/MOD13Q1") .filterBounds(geometry) .filterDate("2000-01-01",...
2
votes
2answers
48 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 ...