Each obspack file has a header with metadata and this function reads selected fields from the metadata and add them as columns. This new columns are used later to be filtered
Usage
obs_read(
index,
categories = "flask",
expr = NULL,
verbose = TRUE,
n_site_code = 15,
n_site_latitude = 18,
n_site_longitude = 19,
n_site_name = 15,
n_site_country = 18,
n_dataset_project = 21,
n_lab = 16,
n_scales = 31,
n_site_elevation = 20,
n_altitude_comment = 22,
n_utc = 18,
fill_value = -1e+34,
as_list = FALSE
)Arguments
- index
data.table
- categories
character; ONE category : of c("aircraft-pfp", "aircraft-insitu", "surface-insitu", "tower-insitu", "aircore", "surface-pfp", "shipboard-insitu", "flask").
- expr
String expressions to filter data.table internally
- verbose
Logical to show more information
- n_site_code
number of characters extratced from metadata after search
- n_site_latitude
number of characters extracted from metadata after search
- n_site_longitude
number of characters extracted from metadata after search
- n_site_name
number of characters extracted from metadata after search
- n_site_country
number of characters extracted from metadata after search
- n_dataset_project
number of characters extracted from metadata after search
- n_lab
number of characters extracted from metadata after search
- n_scales
number of characters extracted from metadata after search
- n_site_elevation
number of characters extracted from metadata after search
- n_altitude_comment
number of characters extracted from metadata after search
- n_utc
number of characters extracted from metadata after search
- fill_value
fill value. Appeared in aoa_aircraft-flask_19_allvalid.txt
- as_list
Logical to return as list
Note
The identification of the altitude and type is critical. The approach used here consists of: 1. Identify agl from the name of the tile. 2. If magl not present, search dill_values used in elevation and transform them into NA (not available) 3. If magl is not present, agl = altitude - elevation 4. If there are some NA in elevation, will result some NA in agl 5. A new column is added named `altitude_final` to store agl or asl 6. Another column named `type_altitude` is added to identify "magl" or "masl" 7. If there is any case NA in `altitude_final`, `type_altitude` is "not available"
Then, the relationship with hysplit is:
| type_altitude | hysplit | magl |
| agl | masl | asl |
| not available | f-PBL |
Examples
if (FALSE) { # \dontrun{
# Do not run
obs <- system.file("data-raw", package = "rtorf")
index <- obs_summary(obs)
dt <- obs_read(index)
obs_read(index, expr = "altitude_final == '5800'")
} # }