Differences

This shows you the differences between two versions of the page.

--- load_map [2015/10/12 16:32]
admin
+++ load_map [2026/08/28 03:25] (current)
hermann Sync from local documentation review
@@ Line 1: / Line 1: @@
 ====== Load Map ======
 ===== Description =====
-This functor loads a map from a file. The filename and its path must be specified.
+Loads a map from a file. The file format is determined automatically from the filename's extension. See [[Load Categorical Map]] for loading maps whose cells represent categories.
 ===== Inputs =====
 ^ Name  ^ Type  ^ Description  ^
-| Filename | [[Map Filename Type]]  | Name and path of input map file. File format is automatically selected based on the filename extension. If path is not specified, file location is the same of model script.  |
+| Filename  | [[Map Filename Type]]  | Name and path of the file to load. If no path is given, the file is located relative to the model script.  |
 ===== Optional Inputs =====
 ^ Name  ^ Type  ^ Description  ^ Default Value  ^
-| Null Value  | [[Null Value Type]]  | Additional value used to represent null cells. Cells with such value are also treated as null cells. This is particularly useful for assigning a null value to image files that do not have this definition.  | None  |
+| Null Value  | [[Null Value Type]]  | Additional value to treat as null, alongside the file's own null value if it has one. Useful for assigning a null value to files that do not define one.  | .none  |
-| Load As Sparse  | [[Boolean Value Type]]  | If true, the map is loaded as a sparse image. Sparse images have the advantage of storing only the cells containing non-null values, but they have worse access time.  | False  |
+| Storage Mode  | [[Enum Type]]  | Hint for how the map should be handled: Default follows the memory allocation policy in the application settings; Prefer Memory suggests loading the whole map into memory; Prefer Disk suggests keeping it on disk and loading it on demand, piece by piece; Load As Sparse suggests storing only non-null cells, minimizing storage at the expense of access time. This is only a hint and may be ignored. This is an advanced port.  | Default  |
-| Suffix Digits  | [[Non Negative Integer Value Type]]  | Number of digits used to represent the image file name suffix.  | 0  |
+| Suffix Digits  | [[Non Negative Integer Value Type]]  | Number of digits used to render Step as a filename suffix. If Step needs more digits than this, it is used unmodified. If zero, no suffix is added. This is an advanced port.  | 0  |
-| Step  | [[Non Negative Integer Value Type]]  | Current step or model iteration. Files with the same name and numbered suffixes will be loaded sequentially according to the model step.  | None  |
+| First Window Coordinate X  | [[Real Value Type]]  | X coordinate of one corner of a crop window, in the map's projection units. Must lie within the file's extent. This is an advanced port.  | .none  |
-| Workdir  | [[Workdir Type]]  | Workdir folder path.  | None  |
+| First Window Coordinate Y  | [[Real Value Type]]  | Y coordinate of one corner of a crop window, in the map's projection units. Must lie within the file's extent. This is an advanced port.  | .none  |
+| Second Window Coordinate X  | [[Real Value Type]]  | X coordinate of the opposite corner of the crop window, in the map's projection units. Must lie within the file's extent. This is an advanced port.  | .none  |
+| Second Window Coordinate Y  | [[Real Value Type]]  | Y coordinate of the opposite corner of the crop window, in the map's projection units. Must lie within the file's extent. This is an advanced port.  | .none  |
+| Step  | [[Non Negative Integer Value Type]]  | Current step or model iteration, appended to Filename as a numeric suffix; automatically bound to the innermost compatible container. This is an advanced port.  | .none  |
+| Workdir  | [[Workdir Type]]  | Work directory Filename is relative to; may be a folder or a Zip archive. When not bound, the directory containing the script is used. This is an advanced port.  | .none  |
-===== Output =====
+===== Outputs =====
 ^ Name  ^ Type  ^ Description  ^
-| Map  | [[Map Type]]  | The map loaded by this functor.  |
+| Map  | [[Map Type]]  | Loaded map, or, when the crop window is defined, only the cropped window of it.  |
 ===== Group =====
-[[Functor List#Input/Output | Input/Output]]
+[[Functor List#Input / Output | Input / Output]]
 ===== Notes =====
-See also [[Load Categorical Map]] for loading maps whose cells represent categories.
+When Null Value is given, any cell already equal to the file's own null value (if it defines one) is converted to Null Value, and any non-null cell that happens to equal Null Value is likewise promoted to null — so a value that meant "no data" before loading still means "no data" after, regardless of how the null definition changed.
-If the "Null Value" parameter is specified, any cell corresponding to the original null value of the map, if provided, is converted to the new null value. This ensures that values originally represented by null value still representing null values, even if the null value definition changes. Any non-null value corresponding to the newly defined null value is also promoted to new null value.
+The crop window (First/Second Window Coordinate X/Y) must either be left entirely at .none, loading the map in full, or have all four coordinates defined together; a partially defined window is not accepted.
-For a list of file formats that Load Map can load, the supported [[wp>Map_projection|projections]] and [[wp>Datum_(geodesy)|datums]], check the [[supported map formats#map_formats_supported_for_reading|supported map formats]].
+If Step is .none, the loaded filename has no numeric suffix.
-It is possible to load maps from [[wp>zip_(file_format)|Zip]] archives. See [[useful_tips#loading_files_from_zip_files|this useful tip]] to know how to do it.
+For a list of file formats that Load Map can load, the supported [[wp>Map_projection|projections]] and [[wp>Datum_(geodesy)|datums]], check the [[Supported Map Formats#map_formats_supported_for_reading|supported map formats]].
+It is possible to load maps from [[wp>zip_(file_format)|Zip]] archives; Workdir may point directly to a Zip archive rather than a folder. See [[Useful Tips#loading_files_from_zip_files|this useful tip]] to know how to do it.
 ===== Internal Name =====
 LoadMap
+===== Usage examples =====
+See practical examples of this functor in [[lesson_4|Lesson 4: Opening and Saving maps]]