ndvi: NDVI Data from Alaska

In gapfill: Fill Missing Values in Satellite Data

Description

The dataset was created to test gap-fill algorithms. It mimics a subset of the MODIS NDVI data (product MOD13A1) in the region of Alaska. The data product features one image per 16-day time interval, i.e., 24 images per year. The indicated images (see Image(ndvi)) were downloaded and stored as a 4 dimensional array. Its dimensions correspond to longitude, latitude, day of the year, and year.

Usage

ndvi

Format

Numeric array with 4 dimensions. As indicated by the dimnames of the array:

• dim 1: longitude,

• dim 2: latitude,

• dim 3: day of the year,

• dim 4: year.

The values are NDVI values, and hence, between 0 and 1. Missing values are encoded as NA.

Source

The actual MOD13A data product is available from NASA EOSDIS Land Processes DAAC, USGS Earth Resources Observation and Science (EROS) Center, Sioux Falls, South Dakota https://lpdaac.usgs.gov. MODIS data can be downloaded with the R package MODIS https://r-forge.r-project.org/projects/modis/.

Examples

str(ndvi)
Image(ndvi)

Example output

Loading required package: ggplot2
 num [1:21, 1:21, 1:4, 1:4] 0.522 0.526 0.459 0.492 0.476 ...
 - attr(*, "dimnames")=List of 4
  ..$ : chr [1:21] "-153.032" "-153.012" "-152.992" "-152.973" ...
  ..$ : chr [1:21] "69.1" "69.12" "69.14" "69.16" ...
  ..$ : chr [1:4] "145" "161" "177" "193"
  ..$ : chr [1:4] "2004" "2005" "2006" "2007"

gapfill documentation built on Feb. 12, 2021, 5:06 p.m.