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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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0answers
708 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/...
5
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0answers
255 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 + "\...
3
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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 ...
3
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0answers
453 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
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 ...
2
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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,...
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 (...
2
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0answers
223 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 (...
2
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0answers
495 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
76 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 ...
2
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0answers
186 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 ...
2
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0answers
399 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
246 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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0answers
46 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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0answers
162 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
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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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
404 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
101 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
55 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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548 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
206 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
128 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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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
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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 ...
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0answers
182 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
494 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....
1
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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
40 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
133 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
376 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
184 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
137 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 ...
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0answers
82 views

problem with running raster calculator in grassgis

When I was trying to do NDVI with grassGIS I faced a problem. I cannot run the raster calculation. When I looked to the command console I see that (Sat Feb 21 12:41:58 2015) r.mapcalc ddes = ( ...
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0answers
631 views

Asking linear regression between NDVI and LST using ENVI

Here I have a problem to calculate a linear regression. I Have two images of NDVI and LST derived from Landsat 8 and want to calculate the linear regression for between them obtaining the dry edge and ...
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0answers
830 views

Fitting Time-series Values with a Gaussian Function

I'm trying to fit a stack of NDVI values to a Gaussian model to allow for determining dates of certain NDVI values using Python and NumPy/SciPy. I've attempted to do this with scipy.optimize.curve_fit....
1
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0answers
306 views

Change Detection ArcGIS with multiple dates

I'll explain my aim first: I am trying to create a single raster to represent vegetation resilience, I am doing this via change detection. So far I have created 5 Change detection images, where 2000 ...
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0answers
131 views

Spot NDVI spatial reference system

I have a series of spot NDVI data for Australia and I need to extract some information from it. Unfortunately there is no spatial reference system attached to it. This is one example of the data (HDF ...
0
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0answers
18 views

Pixel-based NDVI time series - Google Earth Engine

I am a newcomer using GEE and now I want to do a NDVI time series. The condition is that it must be based on the result of the pixel, and it need to displayed on the map. I just made the NDVI time ...
0
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0answers
16 views

Error in compareRaster(rasters) : different extent

I'm having this error in NDVI tif layers, however, all the layers have the same extent and resolution. The only difference is an elevation layer (Aster_DEM_UTM).
0
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0answers
68 views

Growing Season Length in Google Earth Engine?

I am trying to estimate growing season length with the MCD12Q2 dataset (Land Cover Dynamics Yearly L3 Global 500 m), which includes dates for the start and end of the growing season (...
0
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0answers
35 views

Landsat 8 Mosaic (NDVI) Overlapping?

I have downloaded 3 satellite images (Landsat 8 OLI TC1P), in three different periods (two images are from Mart 4. 2017. and the one is from Mart 20. 2017). I have joined (made mosaic) them in ENVI ...
0
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0answers
15 views

Atmospheric correction using ERDAS 2014

There are some questions about atmospheric correction using ERDAS. Is it possible to use the atmospheric corrected satellite image to calculate NDVI and LST using ATCOR of ERDAS? If not, I wonder if ...
0
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0answers
61 views

cloudless maximum-value NDVI-composite and saturating values

My aim is to compose cloud free maximum-value NDVI-composite from Svalbard, Norway. Composite is based surface reflectance collection, filtered with dates (growth period) and region of interest. When ...