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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
103 views

r.mapcalculator

I am using QGIS 2.18.25. I'm struggling to use r.mapcalc to calculate the ndvi for a workbook project. R.mapcalculator is shown on the workbook I'm using and seems simpler to use. Is there a plug-in ...
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2answers
205 views

Faulty Landsat 5 and 7 NDVI/ EVI archives in Google Earth Engine

For my research, I need to use NDVI or EVI datasets in Google Earth Engine. I found Landsat 5 and 7 datasets (8 day, 32 day, anual) for both. However, no matter which combination of datasets and dates ...
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0answers
64 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
344 views

Data smoothing of Sentinel-2 NDVI time series chart in Google Earth Engine?

I am exploring Sentinel-2 time-series NDVI with Google Earth Engine. In another post I learned how to plot a NDVI time series chart. I know that there are many smoothing methods for reducing NDVI ...
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1answer
375 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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1answer
260 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....
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1answer
339 views

How do I convert Digital Number (DN) to reflectance in order to analyze NDVI

I'm working with a mapir nir + red camera meaning that its blue band captures nir light and its red captures red normally. I understand that NDVI is calculated using reflectance values. My question ...
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0answers
34 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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1answer
182 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
2k views

Creating Sentinel-2 NDVI time series chart in Google Earth Engine?

I am exploring Sentinel-2 time-series NDVI with Google Earth Engine. In another post (here) I calculated and exported NDVI values from Sentinel-2. Now I would like to create a NDVI time series chart, ...
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1answer
61 views

How do I visualize NDVI values?

Currently, I have the NDVI values, and I transformed it from [-1, 1] to [0, 255]. Now my question is how do I visualize either of these value? My first thought is to make a color map similar to the ...
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1answer
688 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 ------------------...
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1answer
173 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",...
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2answers
438 views

Making stack from many images in Google Earth Engine?

Using the code below, I've computed 20 ndvi images for modis data. How can I stack and save them in a single file? var mod13 = ee.ImageCollection("MODIS/006/MOD13Q1") .filterBounds(geometry) ....
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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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1answer
101 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 ...
2
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1answer
339 views

GEE Export.image.toDrive output not matching bounding box?

I am new to GEE and javascript. Copy-pasting here and there, I managed to put together this code that extracts NDVI from cloud-free Sentinel-2 images on GEE. I created a fusion table from a KML with ...
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1answer
61 views

Classification based on NDVI values of two images

I want to find the areas where the NDVI value were higher then 0.4 at the end of April and NDVI values were lower then 0.3 at the end of June. I have tried to make it using below demonstrated script, ...
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1answer
166 views

Making subset of Sentinel-2 with rasterio?

I am looking for a solution to my problem with rasterio. I want to download just a specific part of the image from AWS based on lat lon coordinates. Rasterio offers a great tool (window) although it ...
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1answer
67 views

Is the resolution of MYD13A2/MOD13A2 ( MODIS 16 day 1km Global Vegetation Indices) erroneous in Google Earth Engine?

The MODIS vegetation indices collection shows a resolution of 111319.4 metres in Google Earth Engine when, in fact, it should be 1000 metres. Below is my code: var Veg = ee.ImageCollection("MODIS/...
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1answer
98 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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0answers
117 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
407 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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1answer
471 views

Exporting an image of NDVI layers

I have calculated the NDVI for my study area. However, I am having challenges to export the NDVI images. I want to export a single image with several NDVI layers. I have tried the mosaic function but ...
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1answer
62 views

Mosaic Landsat Scenes for NDVI Generation

I would Like to generate an NDVI map for my study region, which is positioned between three Landsat scenes. Which method suits: 1) compute NDVI for each Landsat scenes and then mosaic or 2) Mosaic ...
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2answers
414 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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2answers
61 views

Distance measurement

I have calculated NDVI, now I would like to measure the distance from the places which have more vegetation concentration to low to bare concentration areas. which tool in ArcGIS 10.2 will be suitable ...
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0answers
102 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 ...
3
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1answer
162 views

Why vegetation index, NDVI or SAVI is not working in the desert?

Could anyone explain why the vegetation indices are not working in the desert region? I used Landsat 8 image which has been already radiometric/atmospheric corrected. I want to see the fractional ...
1
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1answer
41 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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0answers
84 views

Choosing statistical method for determining different crop types? [closed]

Task: Determining different crop types from satellite imagery. Tools at hand Training data set which includes RGB, longitude and latitude, NDVI and crop type for each pixel (10m by 10m) Test data ...
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1answer
306 views

Analyze time series NDVI using bfast

I would like to study a trend of NDVI data for a specific time interval using bfast package. For this final aim, I read about the necessity to convert my data frame into a time series object in R. ...
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1answer
49 views

Averaging from several rasters [duplicate]

I need to take an average of several rasters using ArcGIS. Suppose there are 6 rasters and want to have an average of all those 6 rasters. How can I do so?
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1answer
68 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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2answers
79 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 ...
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2answers
379 views

Performing Radiometric Calibration of Sequoia Imagery?

I recently bought a used Sequoia camera and when I bought it, I was under the impression that the sun irradiance sensor and calibration plate would calibrate all my images in real time and I wouldn't ...
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2answers
239 views

Is any map with calculated NDVI available online?

Is there any map which has NDVI calculated? Where can I get highest multispectral satellite image which could be zoom to very large extent?
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3answers
64 views

Calculating NDVI of ONLY desired region using ArcGIS Desktop?

I want to Calculate NDVI of my Surrounding Area using Landsat 8. I have Calculated NDVI but it is rather a very big region. Can NDVI be calculated for a small specified region or can I extract my ...
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3answers
123 views

NDVI error over vegetated surfaces and water

I performed an NDVI analysis using Qgis 2.18 'Las Palmas' of an area of Landsat 7 (wrs_path 168, wrs_row 061),date 2007-12-25 and Landsat 8 (same path and row) date 2017-12-28. I clipped both images ...
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1answer
107 views

NDVI calculation of Color-Infrared Image in Arcpy

I have a color infrared image of an agricultural field. The color infrared image contains 3 different bands; NIR, Red, and Green (order maintained here). To calculate the NDVI, I am currently using ...
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1answer
74 views

Purchasing NDVI imagery for South Western England? [closed]

I am working on a project developing an application for livestock farmers where they can monitor their feed using satellite data. The main aim is to calculate the biomass of a field of grass. The ...
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1answer
68 views

Saving NDVI TIFF file as txt file in ArcGIS Desktop?

I have to use elevation data (dem.tif) and NDVI data (ndvi.tif) as covariates for regression kriging and I want both these files as txt files. How do I do this?
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1answer
123 views

g.getOutputs is not a function while Creating a Chart from a Series

I created a Time Series of NDVI from Sentinel 2 Data, now I want to Chart it, using the following code. I get the error g.getOutputs is not a function I never used g.getOutputs, and from what I read, ...
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2answers
49 views

ArcGIS: NDVI average for bare soil

In ArcGIS I have a 3 Landsat NDVI datasets for 3 consecutive months and would like to calculate the mean bare soil (in hectares) for which I have manually worked out to be between the values of 105 ...
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0answers
165 views

How to compare 2 NDVI images using python?

I want to compare NDVI of 2 images(TIF) of the same area of interest using python. My end result is to get the region on the image where NDVI is decreased(to depict crop damage). Problem: Images have ...
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0answers
56 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
36 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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0answers
550 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
207 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
129 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 ...