All Questions
42 questions
0
votes
0
answers
37
views
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
1
vote
2
answers
584
views
I want to test the statistical significance of the NDVI change in R
I have 20 Sentinel 2 satellite data for the period from 2017 to 2020, with 5 satellite scenes each for the months from May to September, covering one vegetation season. I am interested in whether the ...
- 23
1
vote
1
answer
512
views
I want to apply Mann-Kendall test to NDVI of Sentinel 2 data in R
I have 20 Sentinel 2 satellite scenes from 2017 to 2020 with the months from May to September to cover the growing season. I calculated the NDVI of each scene and intersected it with my area of ...
- 23
0
votes
2
answers
348
views
Multiply two rasters in R, one raster has stack of 25 images, and another raster has one image
I want to multiply two rasters (one has 25 images, and the second raster has 1 image). I am using the loop function for multiplication. But I am not getting the results.
library(raster)
library(rgdal)
...
0
votes
0
answers
174
views
Visible light bands and NIR band not aligned in raster block image, need to calculate NDVI
I recently got some 4band images from Planet. When I attempted to calculate NDVI, the results seemed off. Once i got to looking at the bands, I found that the NIR band and the visible light bands were ...
1
vote
0
answers
87
views
Calculate by cell statistics of Image Collection in (R) Google Earth Engine?
I am using Google Earth Engine in R via the rgee package. My goal is to calculate median NDVI for each cell in an image collection. I have an image collection gathered via:
#This is not a reprex
...
- 452
1
vote
1
answer
407
views
RGEE: calculate per pixel maximum NDVI value in a given year
I'm trying to use RGEE to get the yearly maximum NDVI value per pixel. The code I've written however outputs an image consisting of the maximum NDVI value within the whole region (see image below), ...
- 11
1
vote
0
answers
122
views
Creating a loop to create NDVI images from raster stacks and naming them from the file name [closed]
I have been trying to write a loop to go through two folders of Sentinel 2 satellite images (Band 4 and 5) and get a NDVI for each date.
A stack is created for each band, some cropping and resampling ...
1
vote
0
answers
112
views
Creating NDVI tiles from NAIP tiles in R Loop
I have a folder with many 4 band NAIP .tif tiles, band 1 = Red, band 4 = NIR. In R I would like to create/calculate unsigned 8-bit NDVI images for each of the tiles in a folder. I would like to write ...
- 67
1
vote
0
answers
1k
views
Modified Chlorophyll Absorption Ratio Index (MCARI) vs Green Chlorophyll Index (GCI) in a desert
I am using UAV multispectral data to compute different vegetation indices. Both of these indices were computed with the purpose of seeing/assessing the chlorophyll content, thus indicating if the ...
- 1,244
1
vote
0
answers
385
views
MSAVI vs NDVI for deserts
I calculated NDVI (Normalised Difference Vegetation Index) and MSAVI (Modified Soil Adjusted Vegetation Index) for a desert environment, where most of the vegetation is shrubs with some trees using ...
- 1,244
0
votes
1
answer
658
views
Perform a Thiel-Sen regression on a raster stack in R
I have a raster stack of 20 layers. Each layer represent accumulated NDVI values for the growing season for each year spanning my period of study.
I want to perform a trend analysis using Thiel-Sen ...
0
votes
2
answers
305
views
Focal statistics means for very large area of NDVI raster to be used to extract value to points [closed]
I have tried using ArcGIS Pro running on server, NDVI from Living Atlas, and 30,000 points covering the entire eastern half of Colorado to get the mean NDVI mean value around each point for 270 meters
...
- 315
3
votes
3
answers
2k
views
Issue with scaling factors for Landsat Collection 2 Level 2 data when calculating NDVI
I'm trying to calculate the NDVI for a scene, and I've downloaded Landsat 8 OLI/TIRS Collection 2 Level 2 data, which means it has already been processed to surface reflectance.
The scaling factors ...
- 31
0
votes
0
answers
1k
views
Extracting NDVI values from MODIS datasets in R
Firstly, I'll provide a bit of context behind my question. I've been reading a paper about bushfire modelling, and the paper uses the MODIS datasets (this is my first time learning about them). In ...
5
votes
1
answer
784
views
Rescale NDVI (-1:1) to 0-255 using R
I am trying to rescale my NDVI band (-1:1) to 0:255. I am trying to follow the approach in this post: Rescale raster in R , but I am getting NA values.
# my ndvi
ndvi
class : RasterLayer
band ...
- 1,044
1
vote
0
answers
714
views
R MODIS MOD13Q1 - How to handle data quality issues?
I'm running into some issues with 250m 16-day MOD13Q1 NDVI data using the MODIS package in R.
Looking at the following raster plot, there are certain days where the NDVI does not match the true ...
- 312
1
vote
1
answer
1k
views
Analyze time series NDVI using bfast
I would like to study a trend of NDVI data for a specific time interval using bfast package.
For this final aim, I read about the necessity to convert my data frame into a time series object in R. ...
- 83
2
votes
0
answers
245
views
Using Band Math in R Creates Raster with Different Coordinate System?
I am trying to make a simple NDVI raster from a Landsat 8 image (containing bands 2-7). The Landsat image has a Coordinate System of NAD_1983_UTM_Zone_11N (and datum: D_North_American_1983). When I ...
- 916
1
vote
0
answers
349
views
How can I fill NA values in my NDVI Data? [closed]
I have been trying for weeks now to clean my NDVI data. I know that I have to apply Savitzky-Golay filter to smoothen my data. But before that, I have to fill the missing values in my data. I am ...
- 43
0
votes
2
answers
802
views
how to loop ndvi using R in sentinel-2
I have a two different stacks: one for band 4 (RED) and other with band 8 (NIR).
I'm trying to loop the calculation of NDVI in an area of interest using R.
Well, this is the loop that I'm trying to ...
2
votes
1
answer
960
views
Troubleshooting downloading MODIS NDVI Data in R
I am trying to download MODIS Data from 2000-2018, however I am encountering some difficulties.
Here is my script
MODISoptions(localArcPath = "/Volumes/myserver/MODIS/data",
...
- 21
4
votes
1
answer
2k
views
NDVI-time series with missing values
I have a Landsat-NDVI-time series from 2013 - 2017 with 23 observations per year (115 scenes in total). My goal is to get a smooth time series for a selected single pixel (maybe by using a Savitzky-...
- 137
-1
votes
1
answer
1k
views
Performing Cokriging in R? [closed]
I would like to perform cokriging of 60 observed data points. In the shapefile, there are 60 fields containing the observations as Time 1 to Time 60.
I also have 60 rasters in tiff format. I want to ...
- 1,188
-2
votes
1
answer
623
views
Looping for NDVI in different file paths using R? [closed]
I have different bands separated in different file directory.
I used Raster Calculator to calculate NDVI using "NIR1.tif"-"RED1.tif"/"NIR1.tif"+"RED1.tif" as formula.
The link below describes a loop ...
- 1,188
1
vote
1
answer
571
views
MODIS data for entire Earth Surface with ModisDownload in R
I am trying to use the ModisDownload function from the rts package to download, mosaic and reproject NDVI data from MODIS for the entire Earth surface. I have successfully done that for a subset ...
1
vote
1
answer
246
views
ModisDownload - doubts when using MRT tool
I am using the incredible MODISDownload function from the rts package in R to download NDVI data on vegetation index in Africa.
I have two questions.
I am using the latest version of the package ...
7
votes
1
answer
8k
views
Using a fixed palette range to plot an NDVI raster in R
I would like to plot an NDVI raster with rasterVis packages using the normalized colors from red to green. I don't understand how fix the color scale from 0 to 1 even if my raster value are between 0....
- 729
1
vote
3
answers
1k
views
Processing landsat 8 to make NDVI in R
I want to do the NDVI with images landsat 8 in R, radiometric correction, radiance and reflectance, I make it from the models of the USGS (model here)
But taking the image (ND) for the calculation of ...
- 316
4
votes
1
answer
2k
views
landsat NDVI time series plot in R, based on point or pixel
I am using R language and I would like to create a NDVI time series plot, NDVI vs time, based on irregular intervaled landsat images. I have found a method to create a raster stack and plot the ...
- 529
6
votes
1
answer
3k
views
Pixel-wize trend analysis of an irregular time series stack of NDVI rasters in R
I'm interested in doing a pixel-wize trend analysis of a series of NDVI images from Landsat in R.
The problem is that my images are not exactly happening at regular intervals. But decent imagery of ...
- 307
1
vote
2
answers
2k
views
How to define season by month and average data
I have 10 year NDVI data i.e. two values per month. I would like to average values within a season e.g Season A (January, February and March) per year and plot a graph. y axis=average ndvi value, x ...
- 373
1
vote
1
answer
375
views
Pixel based 10 year NDVI time series
I would to do pixel based 10 year NDVI time series analysis using MODIS data. I’ve 3 seasons in a year. Should I average all values in the study area per season?
- 373
1
vote
1
answer
2k
views
Remove raster pixel in R
This is the 32 year trend NDVI (raster data)
I would like to remove the green grids data by using R (the green pixel value is larger than 0.03)
and this one is R code that i use but i cannot remove ...
- 51
1
vote
1
answer
228
views
Matching Decedal Average NDVI and Worldclim Data
Ive never used NDVI (or EVI) datasets in R. Does anyone have any resource I could use to access a decadal average NDVI dataset for the globe. It would be preferable if this dataset was also comparable ...
- 757
0
votes
0
answers
1k
views
Downloading NOAA AVHRR NDVI using R
I am using the gimms package to automatically download NDVI data from 1981-2013. The code is provided here. The data is available here. However, after running it shows that data has been downloaded ...
- 498
-2
votes
1
answer
3k
views
Using R calculating NDVI [duplicate]
Is there any function to calculate statistical NDVI in landsat8 package
- 421
3
votes
1
answer
3k
views
Using Loop for calculating NDVI in R?
I am using MOD09Q1 now and I would like to calculating NDVI whole year data. One year, I have 46 band 1 images and 46 band 2 images.
list.files
I creating list of band 1 and list of band 2.
...
- 57
0
votes
2
answers
1k
views
Error in which.max() : not yet implemented for large objects in R
I am going to create raster by Julian day that observed maximum value of NDVI within a single year. Actually, I want to know which julian day (or raster) has max value in each cells and get result by ...
- 315
0
votes
2
answers
589
views
How to create raster map by day that observed maximum NDVI from multiple raster data in R?
I have 11 NDVI raster data, representing single summer. I want to create raster by day (Julian day or name of raster) that observed maximum value.
In other words, I want to know which day (which ...
- 315
1
vote
1
answer
4k
views
How to process MODIS ndvi data using QGIS/GRASS/R?
I have MODIS ndvi data (MODIS_Grid_16 days NDVI) from the iberian peninsula (3 tiles), from February of 2000 to August of 2012 (really big data). I want to know how to deal with this kind of files.
My ...
- 215
0
votes
1
answer
3k
views
How to create a loop in R to average ndvi raster time series?
I have monthly ndvi raster geotiffs for multiple years. I need to run a loop to get the average of each of these ndvi grids/rasters.
Each of my ndvi rasters contains 143 pixels. I would like the ...
