Questions tagged [time-series]

Series of data points indexed in time order.

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Dynamic stats in the decoration title lable, by time stamp, in QGIS

I am trying to create a visualisation method of simple stats using the title label in QGIS canvas. I need to observe temporal changes in the stats, so I have tried to specify a dynamic chunk of text ...
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16 views

Cloud filtering Landsat collection 2 over specific regions

I'm trying to filter clouds over a specific region for Landsat collection 2 images. I saw different answers for collection 1 which won't work for collection 2 images. Does anyone have an idea how to ...
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1 answer
27 views

rkt Package function on time series analysis is returning error

I am working with an NDVI time series raster composite (1989 to 2019). I am running a time series function on each pixel of the raster stack using the R code provided by Pironkova et al. 2018. The ...
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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'))...
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56 views

How to Calculate AVI (Advanced vegetation Index) using sentinel 2 Data in GEE

I am trying to download time series data of AVI using Sentinel 2 also I want to make a time series chart? This is my code: var batch = require('users/fitoprincipe/geetools:batch') var avi = function(...
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1 answer
60 views

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 ...
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4 votes
2 answers
113 views

Populating field with sequential timestamp in QGIS

I have a point layer in a GeoPackage with this attribute table. name id timestamp A 1 23:03:2022T23:30:00 A 2 A 3 ... B 1 23:03:2022T23:30:00 B 2 B 3 .....
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70 views

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 ...
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Merge ERA5-Land and ERA5 time series

I am merging some ERA5-Land and ERA5 (netCDF) time series: extract individual ERA5 and ERA5-Land maps and apply scale and offset factors -- this by looping the following for BAND in $(seq 1 8784) ;...
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21 views

Error in Google Earth Engine: No features contain non-null values of "system:time_start"

Here is my code and I want to find the NDVI in this period of time. However, there is a error that is about system:time_start. function maskS2clouds(image) { var qa = image.select('QA60'); var ...
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38 views

R time_to_event function gives an error

I am using the time_to_event function (spatialEco) on a raster time series. The function works when I run the example in the vignette, but when I apply it to my dataset I got this error. Error in if (...
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117 views

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 ...
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Land cover change detection using raster calculator in QGIS

I am trying to find the difference between land cover data from two years. I have used the same classification for both the raster files. For eg: 1-Agriculture 2-Forest 3-Urban 4-Water bodies 5-Barren ...
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1 answer
100 views

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 ...
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1 answer
45 views

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: ...
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Create colour-coded raster from timeseries of binary GeoTIFFs based on date of pixel change

I am studying seasonal snowmelt patterns and have a timeseries of 10 .tif images (one every 2 weeks) over my study area in which a pixel value of 1=water and 0=no water. I was wondering how I could ...
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Extracting the monthly evaporation time series from Google Earth Engine for a point

I am trying to get a time series of monthly evaporation for a point, but I get the error message: FeatureCollection (Error) User memory limit exceeded. Apparently there is an error somewhere that I ...
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23 views

How to convert data/time data into integer to use the histogram widget at CARTO

I want to use the histogram widget at CARTO Builder as time-series widget doesn't have that level of granularity. I have date and time data but how can I convert it into numbers as the histogram ...
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113 views

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 ...
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1 answer
78 views

Generate a time series for a buffer point on Google Earth Engine

I am trying to extract the time series of soil moisture by applying a 500 m radius buffer to the point defined by mapping the bufferPoints function over the FeatureCollection, using the following code:...
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2 votes
1 answer
83 views

Counting points in polygon by time / attribute condition

I have two tables in different databases I cannot connect directly. Table A contains polygons of regions. Table B contains points with timestamps. I want to count the points in each polygon for a ...
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3 votes
1 answer
115 views

Downloading entire image collection of a particular month from 1990-2020 in GEE platform?

I am trying to download ERA-5 daily minimum temperature data of 10 years (2010-2020) for a particular month (at present for November) and a study area (an imported shapefile as WH). I have extracted ...
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1 vote
1 answer
94 views

Extract the monthly soil moisture for a point from Google Earth Engine and export it in CSV format

I am writing a script to extract the time series of soil moisture values from the SMAP soil moisture data using a point shapefile in the Google Earth engine. However in the results I get only 12 ...
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  • 109
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57 views

Error generating chart: No features contain non-null values of "system:time_start". Landsat 8 Surface Temperature Time-Series Chart (Earth Engine)

I want to create an average surface temperature time series chart (+ per year). However I am encountering this error Error generating chart: No features contain non-null values of "system:...
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41 views

How to interpret snowmelt timing script from Google Earth Engine?

I have used this script from Google Earth Engine (GEE) to define the snowmelt timing in Fenoscandia. I am not entirely sure how the mask works for setting the minimum days a pixel has to be covered by ...
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71 views

LST time series chart shows up as a line

Here is the code I am using to create a time series chart representing the LST over a three month period in 2018. However, the mean LST in the chart appears as a straight line representing one ...
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1 answer
55 views

Image time series chart not reading bandName property in doy.SeriesByRegion

Here is part of my code for creating a time series chart in GEE. var addLST = function(image) { var LST = thermal.expression( '(Tb/(1 + (0.00115* (Tb / 1.438))*log(Ep)))-273.15', { 'Tb': thermal....
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2 votes
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73 views

Rainfall trend analysis in Google Earth Engine

I have an image collection of images representing total seaonal rainfall from 1980-2020 in my study area. I want to run an analysis which identifies if a pixel has any significant trends i.e. ...
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1 vote
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23 views

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 ...
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1 answer
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Identifying outliers (not considering spatial relationship) in time-series data

The data I am working on is plant canopy cover (percentage within polygons (0-100%)) estimation from drones. This was collected over the course of 17 weeks. I was thinking on detecting outliers (not ...
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1 vote
1 answer
53 views

Efficient VRT GeoTIFF image stack reading

My aim is to read time series with Python from a stack of spatially aligned GeoTIFF files as efficient as possible. The time series is not only limited to one pixel, but can also relate to a certain ...
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1 vote
1 answer
272 views

Add date annoation for GIF images in Earth Engine

I want to visualize the annual changes on satellite images in Google Earth Engine. I wrote code like this: var geometry = ee.Geometry.Polygon( [[[30.0014347527015, 37.57084315925745], ...
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42 views

Calculating perimeter time series

I'm a beginner in Google Earth Engine and I found this code and edit it for my purpose: // landsat image collection var landsat = ee.ImageCollection('LANDSAT/LC08/C01/T1_SR') .filterBounds(geometry) ....
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1 vote
1 answer
80 views

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 ...
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  • 97
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2 answers
26 views

Fetch all values from all granules of an ImageMosaic click event

I have sucessfully implemented a time series for an ImageMosaic in OpenLayers, using Geoserver as my processing tool. Additionally, I have implemented an onClick event to fetch values when a user ...
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1 vote
1 answer
128 views

Adding Labels to ui.Chart.seriesByRegion with two lines in GEE

I would like to change the labels for a seriesByRegion chart in GEE. var vegIndices = ee.ImageCollection('MODIS/006/MOD13A1') .filter(ee.Filter.date('2015-01-01', '2020-12-31'))...
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1 answer
184 views

Understanding 'ccdc' algorithm in Google Earth Engine

I want to know how the 'ccdc' algorithm, which is deployed on GEE, detects changes. Does the algorithm use the method on the left, the method on the right, or some other method? ---the picture came ...
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1 vote
1 answer
57 views

How to extract Landsat time series for multiple location

I want to extract Landsat time series for multiple locations. I refer to the code in this tutorial.Because I chose a time period of 2019-01-01 to 2019-12-30, I should get multiple columns of ndvi data,...
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1 vote
2 answers
126 views

Converting hourly data to daily data and chart it in GEE

I'm using the following code to convert hourly data into daily data records. In the first case (Surface Solar Radiation) it works well but in the second case (Mean 2m air temperature) occurs an error ...
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35 views

Changes in Sentinel 1 pre-processing in January 2020. ESA or GEE changed something

Working with Sentinel-1 I noticed different behaviors. Then, to analyze them, I took time-series (mean and standard deviation values) of some land and ocean polygons: The images were downloaded from ...
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1 vote
0 answers
91 views

No difference between Savitzky-Golay 2nd order and 3rd order polynomial curve

I don't understand why there is no difference between Savitzky-Golay 2nd order and 3rd order polynomial curve? Perhaps the 3rd order polynomial curve is overfitted, not sure but the concern is yet not ...
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0 votes
1 answer
105 views

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/...
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1 answer
88 views

Adding a GIF into Experience Builder

I've created a time series animation in ArcGIS Pro and exported it into a GIF. Is it possible to add the time series GIF into Experience Builder and play automatically when I am on that page?
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2 votes
1 answer
77 views

Basemap and shapefile CRS issues [duplicate]

I am trying to overlay a timeseries shapefile over a geographic basemap, but the coordinate systems are not the same. I have set the project CRS to EPSG:4326, hence making the basemap in lat/long. ...
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1 answer
154 views

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 ...
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  • 162
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1 answer
60 views

Remove single (un-mosaicked) tiles after mosaicking image collection by day

I want to create a time-series of Sentinel-2 images that cover my entire study area (instead of individual tiles, since the study area spans 2 tiles). I mosaicked the image collection by day using the ...
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1 answer
88 views

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 (...
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13 views

Extract by mask-timeslider issue

I have an issue with the "extract by mask" tool. My Raster Layer is a layer with time content, so I can start an animation with the timeslider. If I extract it based on a country border ...
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1 vote
1 answer
136 views

How to use MOD11A1 bitmask to select "Good Data Quality" pixels for further LST time series generation in GEE

I'm trying to generate a daily LST time series over a region by selecting only the good quality pixels. The code I've written is attached below along with the dataset description. My aim is to select ...
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  • 27
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1 answer
392 views

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 ...
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