ms_rotate_map {mapscanner}

Rotate maps

Description

Display original and modified maps to determine necessary rotation

Usage

ms_rotate_map(map_original, map_modified, rotation = 0, apply_rotation = FALSE)

Arguments

map_original

File name of the original map without anything drawn over it (either a .pdf or .png; extension will be ignored).

map_modified

File name of the modified version with drawings (either a .pdf or .png; extension will be ignored).

rotation

Rotation value to be applied, generally +/- 90

apply_rotation

If FALSE, display results of rotation without actually applying it; otherwise transform the specified map_modified image according to the specified rotation.

Value

No return value. Function either modifies files on disk by rotating images by the specified amount (if apply_rotation = TRUE), or displays a rotated version of map_original (if apply_rotation = FALSE).

Note

If a call to ms_rectify_map detects potential image rotation, that function will stop and suggest that rotation be applied using this function in order to determine the required degree of image rotation. Values for rotation can be trialled in order to determine the correct value, following which that value can be entered with apply_rotation = TRUE in order to actually apply that rotation to the modified image.