Questions tagged [time-series]

Series of data points indexed in time order.

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Snow cover timeseries in GEE - MODIS NSI - shows zero snow in winter in Norway

I want to make a simple time-series of snow cover in a study area in Norway. I modified the script below from another post: Generation of snow cover area time series in GEE using MODIS Snow Cover ...
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1 answer
31 views

Calculating yearly air temperature mean for selected region ERA5

Using ERA5 data, I am trying to extract the average annual temperature for a region. I am interested in a single value for each year. This is the code I tried to use: //Define area var area = ee....
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2 answers
57 views

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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1 answer
75 views

Smoothen the Sentinel-1 Time Series Graph Using Google Earth Engine

In order to study the growth pattern of crops, I tried to smoothen the Sentinel-1 time series graph using the following code but got the error. Error: ImageCollection (Error) ImageCollection.reduce: ...
1 vote
1 answer
69 views

Coefficient of Variation Timeseries in Google Earth Engine

You can build a timeseries for mean or standard deviation band values over a geometry in Google Earth Engine (see code below). However, there does not appear to be an option to plot a timeseries of ...
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1 answer
32 views

GEE add a constant median band representing the median of pixels within a multipolygon

I have a time series of Sentinel-2 images and I'd like to get a single median EVI index value over a multipolygon representing known land-cover areas in each image and set that as a constant band ...
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1 answer
19 views

Debugging copyproperties when image is null, getting time series for each month

I'm trying to make a collection of Landsat8 images for each month of each year, copying the properties of system:time_start of the first image of each respective month, however some months don't have ...
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28 views

Calculating temporal monthly lag between 2 datasets in Google Earth Engine

I want to calculate how many months pass before the terrestrial water storage reacts and peaks in reaction to precipitation using an raster, time-series Image Collection with 2 bands namely '...
1 vote
1 answer
78 views

Daily IMERG timeseries in Google Earth Engine

I am trying to make an area-averaged time series of daily precipitation (IMERG). I'd use NASA Giovanni, but I need to be able to use my own shapefiles to average the areas. Given the size of the area ...
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Specifying particular year in multi-year time series raster image service when attempting spatial join using ArcGIS Pro

I've been trying to grab land use data over a period of time within a set of polygons, but when attempting a spatial join (either through the right-click menu, through the specific tool or through an ...
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21 views

Generating variable that counts number of points inside buffers in monthly intervals

I am using ArcGIS Pro. I have Sales locations and opening dates (and closing dates if applicable) for retailers in an area. I want to draw buffers and then count the number of other retail locations ...
1 vote
1 answer
34 views

Error Generating Time Series Chart: No features contain non-null values of "system:time_start"

I'm getting the following error while generating the time series chart for Image Collection: Error: No features contain non-null values of "system:time_start". Here is the code that ...
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1 answer
84 views

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:/...
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1 answer
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Performing a k-means clustering with raster time series

I would like to perform a k-means clustering on time series data. I tried doing it with rts package. library(rts) path <- system.file("external", package="rts") lst <- list....
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1 answer
42 views

Extraction of time series simultaneously on different radius bufferpoint on Google Earth Engine

I have this code that extracts the monthly time series of soil moisture, on radius defined by the buffer function: function bufferPoints(radius, bounds) { return function(pt) { pt = ee.Feature(...
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Can I obtain LST time series from Landsat 7 dataset for 2019-21?

I used the below code I got from a similar question for obtaining the time series of LST using Landsat 7 dataset. I am getting error as: Image (Error) reduce.median: Error in map(ID=...
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1 answer
182 views

Calculating snow cover area using MODIS Snow Cover data MOD10A1

I have a code of MODIS snow cover time series analysis, but I want to count the snow pixels covering my AOI and thereafter calculate the area and plot a chart where to incorporate the code in this: ...
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1 answer
45 views

LiDAR derived Canopy Height Differencing extent variability

I am using classified LiDAR to create a canopy height model (CHM) for two LiDAR data sets over time. When I create the CHM I use a filter, -keep_class 5 so the output raster exactly outlines the trees ...
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1 answer
75 views

Cloud filtering Landsat collection 2 time series by region

I'm working on creating an NDVI time series and I'm trying to filter out clouds over a specific region so I wont get huge gaps in the time series. Is there a way to reduce the extent by cloud percent? ...
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61 views

Calculating daily mean wind speed and the mean per polygon over multiple years in Google Earth Engine

I have been trying to obtain the daily mean wind speed per pixel per day, next, I want to calculate the mean of the new pixel values for each of the municipalities in Colombia during the period 2000-...
2 votes
1 answer
66 views

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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1 answer
142 views

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
42 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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1 answer
40 views

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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1 answer
264 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(...
1 vote
1 answer
327 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 ...
4 votes
2 answers
142 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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1 answer
678 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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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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40 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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1 answer
283 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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1 answer
207 views

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 vote
1 answer
256 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 ...
1 vote
1 answer
73 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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2 answers
89 views

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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2 votes
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38 views

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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37 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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0 answers
293 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
131 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
163 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
246 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 ...
1 vote
1 answer
233 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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1 vote
1 answer
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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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0 answers
51 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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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 vote
1 answer
100 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
0 answers
102 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. ...
1 vote
0 answers
25 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 ...
0 votes
1 answer
53 views

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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