R: CERC Atmospheric Dispersion Modelling System (ADMS) data...

importADMS {openair} | R Documentation

## CERC Atmospheric Dispersion Modelling System (ADMS) data import function(s) for openair

### Description

Function(s) to import various ADMS file types into openair. Currently handles ".met", ".bgd", ".mop" and ".pst" file structures. Uses `read.csv` (in `utils`) to read in data, format for R and openair and apply some file structure testing.

### Usage

    importADMS(
      file = file.choose(),
      file.type = "unknown",
      drop.case = TRUE,
      drop.input.dates = TRUE,
      keep.units = TRUE,
      simplify.names = TRUE,
      test.file.structure = TRUE,
      drop.delim = TRUE,
      add.prefixes = TRUE,
      names = NULL,
      ...
    )

### Arguments

`file` | The ADMS file to be imported. Default, `file.choose()` opens browser. Use of `read.csv` (in `utils`) also allows this to be a readable text-mode connection or url (although these options are currently not fully tested).
`file.type` | Type of ADMS file to be imported. With default, "unknown", the import uses the file extension to identify the file type and, where recognised, uses this to identify the file structure and import method to be applied. Where file extension is not recognised the choice may be forced by setting `file.type` to one of the known `file.type` options: "bgd", "met", "mop" or "pst".
`drop.case` | Option to convert all data names to lower case. Default, `TRUE`. Alternative, `FALSE`, returns data with name cases as defined in file.
`drop.input.dates` | Option to remove ADMS "hour", "day", and "year" data columns after generating openair "date" timeseries. Default, `TRUE`. Alternative, `FALSE`, returns both "date" and the associated ADMS data columns as part of openair data frame.
`keep.units` | Option to retain ADMS data units. Default, `TRUE`, retains units (if recoverable) as character vector in data frame comment if defined in `file`. Alternative, `FALSE`, discards units. (NOTE: currently, only `.bgd` and `.pst` files assign units. So, this option is ignored when importing `.met` or `.mop` files.)
`simplify.names` | Option to simplify data names in accordance with common `openair` practices. Default, `TRUE`. Alternative, `FALSE`, returns data with names as interpreted by standard R. (NOTE: Some ADMS file data names include symbols and structures that R does not allow as part of a name, so some renaming is automatic regardless of `simplify.names` setting. For example, brackets or symbols are removed from names or repaced with ".", and names in the form "1/x" may be returned as "X1.x" or "recip.x".)
`test.file.structure` | Option to test file structure before trying to import. Default, `TRUE`, tests for expected file structure and halts import operation if this is not found. Alternative, `FALSE`, attempts import regardless of structure.
`drop.delim` | Option to remove delim columns from the data frame. ADMS .mop files include two columns, "INPUT_DATA:" and "PROCESSED_DATA:", to separate model input and output types. Default, `TRUE`, removes these. Alternative, `FALSE`, retains them as part of import. (Note: Option ignored when importing `.bgd`, `.met` or `.pst` files.)
`add.prefixes` | Option to add prefixes to data names. ADMS .mop files include a number of input and process data types with shared names. Prefixes can be automatically added to these so individual data can be readily identified in the R/openair environment. Default, `TRUE`, adds "process." as a prefix to processed data. Other options include: `FALSE` which uses no prefixes and leave all name rationalisation to R, and character vectors which are treated as the required prefixes. If one vector is sent, this is treated as processed data prefix. If two (or more) vectors are sent, the first and second are treated as the input and processed data prefixes, respectively. For example, the argument (`add.prefixes="out"`) would add the "out" prefix to processed data names, while the argument (`add.prefixes=c("in","out")`) would add "in" and "out" prefixes to input and output data names, respectively. (Note: Option ignored when importing `.bgd`, `.met` or `.pst` files.)
`names` | Option applied by `simplifyNamesADMS` when `simplify.names` is enabled. All names are simplified for the default setting, `NULL`.
`...` | Additional arguments, passed to `read.csv` as part of import operation.

### Details

The `importADMS` function were developed to help import various ADMS file types into openair. In most cases the parent import function should work in default configuration, e.g. `mydata <- importADMS()`. The function currently recognises four file formats: `.bgd`, `.met`, `.mop` and `.pst`. Where other file extensions have been set but the file structure is known, the import call can be forced by, e.g, `mydata <- importADMS(file.type="bgd")`. Other options can be adjusted to provide fine control of the data structuring and renaming.

### Value

In standard use `importADMS()` returns a data frame for use in openair. By comparison to the original file, the resulting data frame is modified as follows:

Time and date information will combined in a single column "date", formatted as a conventional timeseries (`as.POSIX*`). If `drop.input.dates` is enabled data series combined to generated the new "date" data series will also be removed.

If `simplify.names` is enabled common chemical names may be simplified, and some other parameters may be reset to openair standards (e.g. "ws", "wd" and "temp") according to operations defined in `simplifyNamesADMS`. A summary of simplfication operations can be obtained using, e.g., the call `importADMS(simplify.names)`.

If `drop.case` is enabled all upper case characters in names will be converted to lower case.

If `keep.units` is enabled data units information may also be retained as part of the data frame comment if available.

With `.mop` files, input and processed data series names may also been modified on the basis of `drop.delim` and `add.prefixes` settings

### Note

Times are assumed to be in GMT. Zero wind directions reset to 360 as part of `.mop` file import.

### Author(s)

Karl Ropkins, David Carslaw and Matthew Williams (CERC).

### See Also

Generic import function `import`, for possible alternative import methods. Other dedicated import functions available for other file types, including `importKCL`, `importAURN`, etc.

### Examples

    ##########
    #example 1
    ##########
    #To be confirmed

    #all current simplify.names operations
    importADMS(simplify.names)

    #to see what simplify.names does to adms data series name PHI
    new.name <- importADMS(simplify.names, names="PHI")
    new.name

[Package openair version 2.8-5 Index]