A [Task](#task) is the basic processing unit of WebODM. To compute an orthophoto, point cloud and textured model from a set of images, you need to create a [Task](#task).
Field | Type | Description
----- | ---- | -----------
id | int | Unique identifier
project | int | [Project](#project) ID the task belongs to
processing_node | int | The ID of the [Processing Node](#processing-node) this task has been assigned to, or `null` if no [Processing Node](#processing-node) has been assigned.
can_rerun_from | string[] | List of possible "rerun-from" options that this task could restart from, given its currently assigned processing node. If this is an empty list, the task can only be restarted from the start of the pipeline.
processing_time | int | Milliseconds that have elapsed since the start of processing, or `-1` if no information is available. Useful for displaying a time status report to the user.
auto_processing_node | boolean | Whether WebODM should automatically assign the next available [Processing Node](#processing-node) to process this [Task](#task). A user can set this to `false` to manually choose a [Processing Node](#processing-node).
last_error | string | The last error message reported by a [Processing Node](#processing-node) in case of processing failure.
options | JSON[] | JSON-encoded list of name/value pairs, where each pair represents a command line option to be passed to a [Processing Node](#processing-node).
processing_node | | null | The ID of the [Processing Node](#processing-node) this [Task](#task) should be assigned to. If not specified, and auto_processing_node is `true`, a [Processing Node](#processing-node) will be automatically assigned.
auto_processing_node | | true | Whether WebODM should automatically assign the next available [Processing Node](#processing-node) to process this [Task](#task).
options | | "[]" | JSON-encoded list of name/value pairs, where each pair represents a command line option to be passed to a [Processing Node](#processing-node).
After a task has been successfully processed, the user can download several assets from this URL. Not all assets are always available. For example if GPS information is missing from the input images, the `orthophoto.tif` asset will be missing. You can check the `available_assets` property of a [Task](#task) to see which assets are available for download.
After a task has been successfully processed, its assets are stored in a directory on the file system. This API call allows direct access to the files in that directory (by default: `WebODM/app/media/project/{project_id}/task/{task_id}/assets`). This can be useful to those applications that want to stream a `Potree` dataset, or render a textured 3D model on the fly.
These paths could change in future versions of WebODM. If the asset you need can be reached via <b>/api/projects/{project_id}/tasks/download/{asset}</b>, use that instead.
As a [Task](#task) is being processed, processing nodes will return an output string that can be used for debugging and informative purposes. Output is only available after processing has started.
Parameter | Required | Default | Description
--------- | -------- | ------- | -----------
line | | 0 | Only display the output starting from a certain line number. This can be useful to display output in realtime to the user by keeping track of the number of lines that have been displayed to the user so far and thus avoiding to download all output at every request.
If a [Task](#task) has been canceled or has failed processing, or has completed but the user decided to change processing options, it can be restarted. If the [Processing Node](#processing-node) assigned to the [Task](#task) has not changed, processing will happen more quickly compared to creating a new [Task](#task), since the [Processing Node](#processing-node) remembers the `uuid` of the [Task](#task) and will attempt to reuse previous results from the computation pipeline.
After a task has been successfully processed, a TMS layer is made available for inclusion in programs such as [Leaflet](http://leafletjs.com/) or [Cesium](http://cesiumjs.org).
<asideclass="notice">If you use <ahref="http://leafletjs.com/"target="_blank">Leaflet</a>, you'll need to pass the authentication token via querystring: /api/projects/{project_id}/tasks/{task_id}/tiles/{Z}/{X}/{Y}.png?jwt=your_token</aside>
