Questions tagged [ndvi]
Normalized Difference Vegetation Index is used to quickly identify vegetation and its condition in remotely-sensed data.
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2answers
24 views
Google Engine - Make a greenest pixel composite for Sentinel 2
Does anyone know how to do a composite of greenest pixel for Sentinel 2?
That is calculate the maximum NDVI for a Image collection, and then do a pixel-wise image stacking of the original bands (...
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0answers
3 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).
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0answers
15 views
Exporting a masked image in Google Earth Engine? [closed]
I'd like to know how I can export a large image into a single image. Exporting this NDVI map composite would require me to mosaic it somewhere else.
Can you help me construct the right script for ...
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0answers
16 views
shortest code for application of Savitzky-Golay filter to the MYD13Q1 NDVI is needed [closed]
Can anyone please show me working python code for smoothing MYD13Q1 products through Savitzky-Golay filter, which are represented by raster files?
The problem is that there are separate codes which ...
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1answer
34 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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0answers
22 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 (...
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0answers
24 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 ...
1
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1answer
26 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 ...
1
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1answer
40 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 ...
2
votes
1answer
38 views
Create animation of NDVI from ImageCollection in GEE
I'm trying to make an animation of NDVI images from sentinel collection in order to see clearly variance in the field.
The first part of the code works with little error: "Layer name is not a string: ...
1
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1answer
21 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 ...
-2
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0answers
18 views
Pixel-Level NDVI : what is it
I have basic knowledge on how to compute floating or integer based NDVI value of an AOI on daily, weekly, monthly or yearly scenes BUT do not understand what is meant by pixel-level NDVI value. ...
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1answer
39 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 ...
1
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1answer
61 views
Make a Loop for Monthly NDVI in Google Earth Engine?
I've computed maximum NDVI for each month. but I don't know how can I write this code through a loop in Google Earth Engine?
code link: https://code.earthengine.google.com/...
1
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1answer
39 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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0answers
11 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 ...
2
votes
1answer
47 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 ...
3
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1answer
43 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 ...
1
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1answer
54 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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0answers
20 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 ...
0
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1answer
29 views
NDVI Analysis of a small area from the year 2000- 2011 [closed]
I want to perform an NDVI analysis in a small area. I want to see the change around a river body for the year 2002, 2005, 2008, 2010 and 2011. I tried using Landsat-7 data but due to the scanline ...
1
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1answer
43 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
46 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 ...
2
votes
2answers
56 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 ...
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1answer
28 views
Select observations based on Quality Bands , Google Earth Engine
From the following NDVI collection, I want to keep only the observations with Good Quality (equal to zero).
I try to do this with the SummaryQA but I get "Pattern 'SummaryQA' did not match any bands"...
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1answer
29 views
Unable to transform features into projection, Google Earth Engine
I have the following code with which I try to export the MODIS NDVI index.
I have rescaled the collection with the appropriate scale factor and code runs without errors.
When I try though to download ...
0
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0answers
26 views
How to retrieve GIS data in Multiple Orthophoto at point level
I have been using a python script that can read Data from Orthophoto(*.tiff) of size 300Mb-2Gb. But this is taking 32s per request of lat-long, which is not ok.
I have different Orthophotos with ...
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1answer
40 views
Centroid value extraction of Landsat image collection in Google Earth Engine
I have an NDVI collection wich I have created from the combination of different collections Landsat5 and 7.
How can I exctract the NDVI values of the centroids of each pixel, of each image from my ...
2
votes
1answer
58 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 ...
0
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0answers
25 views
NDVI from SRGB image
I have a SRGB image from which I need to get the NDVI value.
I know how to calculate the NDVI, but it does not work with this SRGB image.
0
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1answer
19 views
How to determine the average NDVI value of a selected area?
I'm new to ArcMap 10.2 and trying to get NDVI data of city centers.
So my problem is, after I'm calculating the NDVI and getting the result raster, I would like to get a mean (average) value of ...
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1answer
52 views
Use Google Earth Engine to stack NDVI timeseries layers into one image and export
I would like to export the NDVI with the date in the filename in one image. Now I can only export them respectively.
And when I export the NDVI image, it shows the error "Error: Exported bands must ...
3
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1answer
89 views
Treatment of Landsat 7 SLC error in Google Earth Engine?
Google Earth Engine distributes Landsat 7 image composites of indeces such as NDWI and NDVI that, when averaged on a shapefile, give back a coherent value.
But how is SLC failure treated by it https:/...
1
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0answers
88 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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1answer
66 views
Why does the raster calculator only give out 1 and 0 values
I have a problem with the raster calculator of ArcMap 10.5.1 because it only gives out a raster with 0 an 1 values. I'd like to calculate the Leaf Area Index out of a NDVI-Raster by using this ...
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1answer
70 views
Google Earth Engine equation for fractional vegetation using NDVI
I want to write an equation for fractional vegetation in Google Earth Engine using NDVI.
My code is;
var ndviClip = ndvi.clip(table);
Map.addLayer(ndviClip, {min: -1, max: 1, palette: ['FF0000', '...
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1answer
66 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
99 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 ...
0
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0answers
49 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':
...
2
votes
1answer
186 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 ...
1
vote
1answer
183 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'...
3
votes
1answer
170 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....
0
votes
1answer
190 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 ...
1
vote
0answers
27 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
94 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");
...
2
votes
1answer
659 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, ...
0
votes
1answer
44 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 ...
2
votes
1answer
337 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
91 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",...
1
vote
2answers
201 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)
....
