All Questions
Tagged with ndvi time-series
62 questions
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50
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NDVI for Landsat gives results for the entire world
I am trying to get NDVI from Landsat-8 for a region starting from 2013 uptil Sep 2024 in Google Earth Engine. I am attempting time series and am looking for results for every month for all these years ...
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0
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33
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How to analyze NDVI time series data
I am analyzing time series data of NDVI within an AOI.
Ultimately, I would like to plot the average monthly data in a box-and-whisker diagram.
Here is the problem.
The number of months with ...
- 23
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0
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37
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Convert irregular time series to regular for running bfast model
I have NDVI rasters extracted from Sentinel-2 with irregular time series over a year and missing data of July. I would like to generate the irregular time series to a monthly regular time series in R ...
- 379
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votes
1
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27
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Extract, plot and export as a table a vegetation index time series from multipoint feature collection in Earth Engine
Reference is to a tread I posed years ago and was solved Extract pixel values from several bands of an image and export in a single table in Google Earth Engine
The challenge now is to create S2 NDVI ...
- 531
0
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1
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105
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Eliminating missing pixels in NDVI time series analysis by temporal gap filling with linear interpolation to get a smooth result
The code is running correctly but it doesn't give me a smoothened result. Anyone who can help me out?
var startDate = '2015-01-01';
var endDate = '2023-12-31';
var images = sentinel.filter(ee.Filter....
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0
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1
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36
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Trying to create mask to eliminate false NDVI numbers in GEE time series analysis using Sentinel data
It keeps given me the error that ndvi.gte is not a function, I shared my code below:
var images = sentinel.filter(ee.Filter.date(startDate,endDate)).filterBounds(geometry)
print(images);
var ndvi = ...
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0
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1
answer
121
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Unable to compute graph in Google Earth Engine when trying to compute mODIS NDVI Time series analysis of a small region in Crete, Greece
I want to make a simple time series analysis of the past 8 years using MODIS data but I'm unable to compute the graph as I get the following message:
Error generating chart: Collection.first: ...
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1
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0
answers
137
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Creating interactive chart in Jupyter Notebook using Geemap
This code applied the custom date to the x-axis. But I do not want this. I want to show the date on which the Image is taken by using "system:index" property of the Image. Also, This code ...
- 131
1
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1
answer
172
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Creating NDVI and Cloud Chart in Jupyter Notebook
I am trying to calculate NDVI and cloud pixel percentage. I have successfully done this but I am facing a problem in creating a chart of it in Jupyter Notebook, as I am new to Python so I tried ...
- 131
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1
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119
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EEException: Image.bandNames: Parameter 'image' is required
I am trying to compute the NDVI index using the MODIS Landset in Python and to visualize it in a time series chart, but I am facing an error and I cannot understand where is the problem. This is my ...
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0
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230
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Using geemap to apply Otsu's threshold on time series NDVI slope
I'm running geemap on Google Colab, and try to apply Otsu's threshold to a Sentinel-2 time series NDVI, the threshold is when the NDVI slope is greater than 0.5.
But when I try to apply the otsu ...
1
vote
1
answer
143
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Why can I add data as a map layer, but not be able to export it in GEE?
I have put together a script in earth engine with the purpose of producing an NDVI max time-series collection with relevant masks applied from 1984-2022, then reducing this using Kendall's correlation ...
0
votes
1
answer
143
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Removal of atypical images from a time series NDVI sentinel-2 Google Earth Engine
I'm new to GEE.
How can I automatically remove by scanning sentinel-2 NDVI images from a collection of images, which contain outliers in their time series by taking into account the before and after ...
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1
vote
1
answer
206
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Calculating 2022 NDVI time series
I calculated seasonal NDVI Time series (1 image for each season) from 2017 to 2022 using Sentinel-2 L1C images (which I converted to L2A using Sen2Cor), the first 5 years where ok, but the last 3 ...
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0
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1
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153
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Adding system:time_start to a reduced modis collection?
I need to add a system:time_start to a reduced modis collection. I am trying to get monthly maximum NDVI values but the system time start gets lost during the reducing processs and i am unsure of ...
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3
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736
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Google Earth Engine: running NDVI analysis by month
How would I go about making my analysis values per month rather than per year
Create date filter and vector of years for analysis
var date_filter = ee.Filter.date('2010-06-22', '2022-06-22');
...
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0
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1
answer
455
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Error in generating a chart: No images in the collection intersect the specified regions
I am getting an error saying:
no images in the collection intersect the specified regions
thus my time-series chart cannot be generated.
What might be the reason for this?
The link to my code
https:/...
- 69
0
votes
1
answer
679
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Cloud filtering Landsat collection 2 over specific regions
I'm trying to filter clouds over a specific region for an NDVI time series using Landsat collection 2.
I tried filtering with simple cloud score but it doesn't seem to work (maybe because there is no ...
1
vote
1
answer
105
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Error generating chart: No features contain non-null values of "system:time_start" in generating chart of NDVI
I got this error when trying to produce a time-series chart of NDVI in Sentinel-2. I've already tried something like .copyProperties(image)".set('system:time_start',image.get('system:time_start'))...
2
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1
answer
1k
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NDVI time series of several areas simultaneously with GEE
I'm not an expert in GEE so I'm relying on pre-compiled scripts that I modify a little at a time.
My goal is this: to make a plot in which I compare the time series of agricultural areas and natural ...
- 395
1
vote
1
answer
3k
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Visualization of Time series data of NDVI using GEE
I am trying to perform Time series of my study area, for a period of 6 years, from 2016-2022 (March) using Sentinel-2 COPERNICUS/S2 dataset, in Google Earth Engine JavaScript Web API.
This is how my ...
- 119
1
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1
answer
1k
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GEE NDVI time series for multiple polygons each with its own date range
My question extends one asked recently and I am working with the code suggested there as answer:
This script takes a set of polygons and for each, averages NDVI over all images within the specific ...
- 646
1
vote
1
answer
874
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NDVI mean in polygon between dates, for a set of polygons
I have a set of stations, each has a start and end date for consideration, and polygon of interest.
For each station, I need to average the NDVI inside the polygon, and then to average the NDVI for ...
- 11
1
vote
1
answer
251
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Empty map error for MODIS NDVI time series on Google Earth Engine
I am trying to get a time series of MODIS NDVI for a point, with the script below and it works quite well, except when I try to include the year 2017 where I get the following error message:
ID: ...
- 165
0
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0
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722
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Creating time series of NDVI data using Landsat 8 imagery
I am trying to calculate the average annual NDVI of Landsat imagery on a forest in Kentucky. The study will occur from 1984-2020. I am writing code specifically for Landsat 8 at the moment, but I plan ...
1
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0
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43
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Characterizing annual NDVI for small site areas with significant time series gaps
I'm looking at 30 years of growing season Landsat 5 NDVI for small areas (three sites, each with 9 pixels). For some years there are only one or two available images due to cloud cover, other years ...
- 11
1
vote
1
answer
550
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Plot time series for NDVI on Landsat8
I want to select a region on a map and get the time series for NDVI based on Landsat 8 imagery.
If possible, it would be better if I can get the image row and path through matching the Landsat tiles ...
- 149
0
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1
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785
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How can I plot NDVI time series from multiple polygon into one graph with a single line instead of one line each polygon?
I want to plot NDVI time series from multiple polygon into one graph with a single line instead of one line for each polygon.
Here's part of my code:
var countries = ee.FeatureCollection("USDOS/...
1
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1
answer
592
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Calculating longterm mean NDVI anomaly
I want to calculate the longterm mean NDVI anomaly at a specific geometry point buffered to 1000m. I have calculated the longterm mean NDVI for the 20 year period. Because I want to calculate NDVI ...
- 320
2
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1
answer
460
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Increasing decimal in table chart Google Earth Engine
I have code that generates NDVI times series chart. The values are with 3 decimal places. I want to increase the decimal places to 4 or 5. Is there a way of doing that?
My code:
// Load raster data (...
- 89
0
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1
answer
1k
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NDVI time series with Sentinel-2 in Google Earth Engine
I want to calculate the time series of the NDVI with Sentinel-2 of a specific area of Australia.
I started from this code:
Time series analysis of NDVI using Google Earth Engine
Substituting Landsat ...
-1
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1
answer
286
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Converting numbered day of year to Month on the X axis for NDVI time series analysis for a range of years [closed]
I am working on an NDVI time-series series analysis to detect incidence pests. Timeseries generated by landcover is okay as I am using ui.Chart.image.series function.
The problem I have is with the ...
- 320
1
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0
answers
741
views
Computing NDVI pixel based timeseries for specific landcover classes in Google Earth Engine for a specific time period
I am trying to optimize my Google Earth Engine to perform a pixel-based NDVI time-series analysis for my four landcover classes (grassland, forest, crops and shrubs). I masked these landcover classes ...
- 320
1
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1
answer
514
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Reducing multiple NDVI timeseries values for single date at pixel level
I am generating an NDVI Timeseries for masked land cover classes using the Copernicus landcover 2019 Global product in Google Earth Engine. I have masked the landcover classes but and I am computing ...
- 320
2
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1
answer
958
views
Computation timed out when exporting time series for a large number of locations from Google Earth Engine
I am trying to export Sentinel-2 NDVI time series for a huge number of fields (n>80000) to a csv file. However I got a 'computation timed out' error after 12 hours of running. Here is the code and ...
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2
votes
2
answers
2k
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Printing max and min values of Landsat NDVI time series to GEE console
I am trying to extract the min and max values of an NDVI time series and print those values to the console, so I could then subtract those values to determine the seasonal stability of an area. Most ...
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1
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0
answers
142
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Create Time Series Chart of NDVI (based on Landsat 5) of a National Park in Germany with Google Earth Engine
So this is my code so far:
My Questions:
How do I name the title and x-axis and y-axis? It isn´t working with
.setOptions({title: 'NDVI Bayrischer Wald Landsat 5 1984 - 2013'}) unfortunately.
How do ...
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2
votes
1
answer
634
views
Problem generating NDVI chart in GEE
I'm new to GEE. I'm currently working on NDVI data analysis. So this is my code for MODIS NDVI. I already run the NDVI scale factor function and do the image collection, Divide by 10000, in images ...
- 49
2
votes
2
answers
2k
views
Adding time as 'year' band to image collection
I have uploaded 35 images (annual maximum NDVI) to GEE and put them manually (drag and drop) together to an image collection. There is no time band, but for the ee.Reducer.linearFit() function, I need ...
- 137
1
vote
1
answer
644
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Create time series chart with linear trend using NDVI values at specific locations (9000) stored in a feature collection in Google Earth Engine
I try to find a correlation between a linear trend of two NDVI time series before and after a specific day in time. And that I want to repeat (iterate/map?) for a lot of points globally distributed. I ...
- 137
2
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1
answer
578
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GEE check only one sentinel tile instead of checking all of them when the featurecollection is in many tiles
I have code in GEE that creates image collection based on geometry, calc for each polygon the mean value of NDVI for each image, creates new featurecollection with the image as title, and then the ...
- 2,215
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1
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249
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Google Engine - NDVI time series by region - LineChart not connecting dots
I created a stack of NDVI images, and also have several polygon. When I plot the time series, points show up but only a few connects dates to each other.
I am using the ui.Chart.image.seriesByRegion()...
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1
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0
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113
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What happens if some polygons are empty in reduce() in Google Earth Engine
I am drawing the NDVI time-series trend for two types polygon in my target area using Sentinel-2. I don't know why I miss one day's NDVI mean. Is it because some polygons are unmasked after cloudrmove?...
- 11
3
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2
answers
2k
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Max NDVI per month & year using Google Earth Engine to CSV - CSV gives -999 values only
This question refers to Calculating NDVI per region, month & year with Google Earth Engine
I have modified the code posted by @Kel Markert at https://code.earthengine.google.com/...
- 115
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1
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1k
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Creating NDVI time series from single polygon of shapefile using Google Earth Engine
I am new in Google Earth Engine, I am trying to plot ndvi timeseries from a single polygon of shapefile, but when I run the code I get "Error generating chart: Collection query aborted after ...
- 105
4
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1
answer
3k
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Time series analysis of NDVI using Google Earth Engine
I want to create a chart of annual NDVI for a specific region. The output should be one NDVI value for that region for each year.
I tried the following code and so far was able to get an image ...
- 130
0
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1
answer
1k
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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 ...
1
vote
1
answer
960
views
NDVI time series chart showing multiple values for the same point in Google Earth Engine
I tried to generate a time series chart of NDVI using Sentinel-2 data for multiple points. But the chart has vertical plots with two values for same point and same date.
Here is the code:
var ...
1
vote
1
answer
368
views
Convert Landcover Raster to Vector to Use for Tracking NDVI Over Time
I want to look at NDVI and other spectral indices over time and compare these time series across different land cover types. I believe I have the code to do this but I'm running into the error that I ...
- 419
1
vote
0
answers
119
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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 ...
- 111