Detects available SAGA GIS installations and configures the environment for calling the SAGA command line interface (`saga_cmd` / `saga_cmd.exe`). Optionally prepares variables commonly used by wrappers such as RSAGA.
The function relies on [findSAGA()] to discover installations (unless a predefined installation table is provided via `default_SAGA`).
Usage
linkSAGA(
default_SAGA = NULL,
searchLocation = "default",
ver_select = FALSE,
quiet = TRUE,
returnPaths = TRUE
)Arguments
- default_SAGA
Optional. Either `NULL` (default; triggers [findSAGA()]) or a `data.frame`-like object describing installations (at least a first column with bin directory paths; a second column may provide module paths on Unix).
- searchLocation
Character. Search root or hint passed to [findSAGA()]. Use `"default"` to search standard locations.
- ver_select
Logical or numeric. If numeric, select the indexed installation. If `TRUE`, interactive selection. If `FALSE`, automatic selection.
- quiet
Logical. Suppress messages.
- returnPaths
Logical. If `TRUE`, return the selection list. If `FALSE`, only perform environment setup (side effects).
Value
A list with elements:
- sagaPath
Selected SAGA bin directory.
- sagaModPath
Selected SAGA module directory (may be empty on Unix in this legacy logic).
- sagaCmd
Full path to the `saga_cmd` executable.
- installed
The detected installation table.
- exist
Logical; `TRUE` if a valid installation was selected.
Details
The selection strategy is:
If exactly one installation is found, it is used.
If multiple are found and `ver_select` is numeric, the indexed installation is used.
If multiple are found and `ver_select = TRUE`, an interactive selection is requested.
If multiple are found and `ver_select = FALSE`, the "latest" entry is chosen (currently: last row; improve later by a numeric version compare).
On Windows, SAGA uses different module folder conventions depending on version (e.g., `tools/` vs `modules/`). This function tries to derive the correct module directory based on the detected version.