Skip to contents

Use Case 2 - Processing a Single Dataset from DataOne

Julien Brun and Kristen Peach, NCEAS

2024-08-20

Source: vignettes/use02_dataset-single-dataone.Rmd
use02_dataset-single-dataone.Rmd

Summary

This vignette aims to showcase a use case using the 2 main functions of metajam - download_d1_data and read_d1_files to download one dataset from the DataOne data repository.

Note on data url provenance when using download_d1_data.R

There are two parameters required to run the download_d1_data.R function in metajam. One is the data url for the dataset you’d like to download.You can retrieve this by navigating to the data package of interest, right-clicking on the download data button, and selecting Copy Link Address.

For several DataOne member nodes (Arctic Data Center, Environmental Data Initiative, and The Knowledge Network for Biocomplexity), metajam users can retrieve the data url from either the ‘home’ site of the member node or the from the DataOne instance of that same data package. For example, if you wanted to download this dataset:

Kelsey J. Solomon, Rebecca J. Bixby, and Catherine M. Pringle. 2021. Diatom Community Data from Coweeta LTER, 2005-2019. Environmental Data Initiative. https://doi.org/10.6073/pasta/25e97f1eb9a8ed2aba8e12388f8dc3dc.

You have two options for where to obtain the data url.

  1. You could navigate to this page on the Environmental Data Initiative site (https://doi.org/10.6073/pasta/25e97f1eb9a8ed2aba8e12388f8dc3dc ) and right-click on the CWT_Hemlock_Diatom_Data.csv link to retrieve this data url: https://portal.edirepository.org/nis/dataviewer?packageid=edi.858.1&entityid=15ad768241d2eeed9f0ba159c2ab8fd5

  2. You could fine this data package on the DataOne site (https://search.dataone.org/view/https%3A%2F%2Fpasta.lternet.edu%2Fpackage%2Fmetadata%2Feml%2Fedi%2F858%2F1) and right-click the Download button next to CWT_Hemlock_Diatom_Data.csv to retrieve this data url:https://cn.dataone.org/cn/v2/resolve/https%3A%2F%2Fpasta.lternet.edu%2Fpackage%2Fdata%2Feml%2Fedi%2F858%2F1%2F15ad768241d2eeed9f0ba159c2ab8fd5

Both will work with metajam! You will get the same output either way.

We have not tested metajam’s compatibility with the home sites of all DataOne member nodes. If you are using metajam to download data from a member node other than ADC, EDI, or KNB we highly recommend retrieving the data url from the DataOne instance of the package (example 2 above).

Metadata format dictates metajam output

We include two examples, one downloading a dataset with metadata in eml (ecological metadata format) and the other downloading a dataset with metadata in ISO (International Organization for Standardization) format.

Example 1: eml

For the first example, we are using Diatom Community Data from Coweeta LTER, 2005-2019: Kelsey J. Solomon, Rebecca J. Bixby, and Catherine M. Pringle. Environmental Data Initiative. https://pasta.lternet.edu/package/metadata/eml/edi/858/1.

Libraries and constants 

# devtools::install_github("NCEAS/metajam")
library(metajam)  
# Directory to save the data set
path_folder <- "Data_coweeta"

# URL to download the dataset from DataONE
data_url <- "https://cn.dataone.org/cn/v2/resolve/https%3A%2F%2Fpasta.lternet.edu%2Fpackage%2Fdata%2Feml%2Fedi%2F858%2F1%2F15ad768241d2eeed9f0ba159c2ab8fd5"

Download the dataset 


# Create the local directory to download the datasets
dir.create(path_folder, showWarnings = FALSE)

# Download the dataset and associated metdata 
data_folder <- metajam::download_d1_data(data_url, path_folder)

At this point, you should have the data and the metadata downloaded inside your main directory; Data_coweeta in this example. metajam organize the files as follow:

  • Each dataset is stored a sub-directory named after the package DOI and the file name
  • Inside this sub-directory, you will find
    • the data: my_data.csv
    • the raw EML with the naming convention file name + __full_metadata.xml: my_data__full_metadata.xml
    • the package level metadata summary with the naming convention file name + __summary_metadata.csv: my_data__summary_metadata.csv
    • If relevant, the attribute level metadata with the naming convention file name + __attribute_metadata.csv: my_data__attribute_metadata.csv
    • If relevant, the factor level metadata with the naming convention file name + __attribute_factor_metadata.csv: my_data__attribute_factor_metadata.csv
Local file structure of a dataset downloaded by metajam

Local file structure of a dataset downloaded by metajam

Read the data and metadata in your R environment 

# Read all the datasets and their associated metadata in as a named list
coweeta_diatom <- metajam::read_d1_files(data_folder)

Structure of the named list object

You have now loaded in your R environment one named list object that contains the data coweeta_diatom$data, the general (summary) metadata coweeta_diatom$summary_metadata - such as title, creators, dates, locations - and the attribute level metadata information coweeta_diatom$attribute_metadata, allowing user to get more information, such as units and definitions of your attributes.

Example 2: iso

For the second example, we are using Marine bird survey observation and density data from Northern Gulf of Alaska LTER cruises, 2018. Kathy Kuletz, Daniel Cushing, and Elizabeth Labunski. Research Workspace. https://doi.org/10.24431/rw1k45w

Libraries and constants 

# devtools::install_github("NCEAS/metajam")
library(metajam)  
# Directory to save the data set
path_folder <- "Data_alaska"

# URL to download the dataset from DataONE
data_url <- "https://cn.dataone.org/cn/v2/resolve/4139539e-94e7-49cc-9c7a-5f879e438b16"

Download the dataset 


# Create the local directory to download the datasets
dir.create(path_folder, showWarnings = FALSE)

# Download the dataset and associated metdata 
data_folder <- metajam::download_d1_data(data_url, path_folder)

At this point, you should have the data and the metadata downloaded inside your main directory; Data_alaska in this example. metajam organize the files as follow:

  • Each dataset is stored a sub-directory named after the package DOI and the file name
  • Inside this sub-directory, you will find
    • the data: my_data.csv
    • the raw EML with the naming convention file name + __full_metadata.xml: my_data__full_metadata.xml
    • the package level metadata summary with the naming convention file name + __summary_metadata.csv: my_data__summary_metadata.csv
Local file structure of a dataset downloaded by metajam

Local file structure of a dataset downloaded by metajam

Read the data and metadata in your R environment 

# Read all the datasets and their associated metadata in as a named list
coweeta_diatom <- metajam::read_d1_files(data_folder)

Structure of the named list object

You have now loaded in your R environment one named list object that contains the data coweeta_diatom$data, the general (summary) metadata coweeta_diatom$summary_metadata - such as title, creators, dates, locations - and the attribute level metadata information coweeta_diatom$attribute_metadata, allowing user to get more information, such as units and definitions of your attributes.

Structure of the named list object containing tabular metadata and data as loaded by metajam

Structure of the named list object containing tabular metadata and data as loaded by metajam