Questions tagged [time-series]
Series of data points indexed in time order.
297
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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 ...
- 43
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votes
1
answer
31
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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....
- 67
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2
answers
57
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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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1
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1
answer
75
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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: ...
- 33
1
vote
1
answer
69
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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
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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 ...
- 27
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1
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19
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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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0
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28
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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 '...
- 21
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1
answer
78
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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 ...
0
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0
answers
14
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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
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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 ...
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1
answer
34
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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
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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
40
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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....
- 133
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1
answer
42
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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(...
- 121
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32
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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
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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
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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 ...
- 359
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1
answer
75
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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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0
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61
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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
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1
answer
66
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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 ...
0
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1
answer
142
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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
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1
answer
42
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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
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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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1
answer
264
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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
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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 ...
- 375
4
votes
2
answers
142
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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
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678
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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 ...
- 107
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1
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107
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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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40
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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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0
answers
40
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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
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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
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1
answer
207
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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 ...
- 13
1
vote
1
answer
256
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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 ...
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1
vote
1
answer
73
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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: ...
- 121
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votes
2
answers
89
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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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2
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0
answers
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 ...
- 121
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0
answers
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 ...
0
votes
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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1
answer
163
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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
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1
answer
246
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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
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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 ...
- 121
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1
answer
88
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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:...
0
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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 ...
- 798
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1
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114
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
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1
answer
100
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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....
- 15
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 ...
- 11
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1
answer
53
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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 ...
