Geoprocessing provides a large suite of tools for performing GIS tasks that range from basic buffer and polygon overlays to complex regression analysis and image classification. You can automate all kinds of GIS workflows using Geoprocessing, from converting a large amount of data from one format to another to using a sequence of operations to model and analyze complex spatial relationships.
- Calculating optimum paths through a transportation network
- Predicting the path of wildfire
- Analyzing and finding patterns in crime locations
- Predicting which areas are prone to landslides
- Predicting flooding effects of a storm
There are many reasons why geoprocessing services are good options for these tasks. They can centralize logic to the service. They can help to reduce the workload on the client. Also, geoprocessing services can access tools that aren’t available or efficient to run in the client.
Geoprocessing is based on a framework of data transformation. A typical geoprocessing tool performs an operation on an ArcGIS dataset (such as a feature class, raster, or table) and produces a new dataset as a result. Each geoprocessing tool performs a focused operation on geographic data, perhaps as a small part of the overall analytical process.
Geoprocessing allows you to combine a sequence of tools into what is called a model. In a model, the output of one tool is fed into another, which allows you to automate your workflows. Geoprocessing tools and models can be shared with others by creating web services. ArcGIS Runtime uses geoprocessing tools through web services.
A geoprocessing tool is a command or function that performs an operation on GIS data. There are three types of tools, as shown in the table below.
Built-in tools are created by Esri and provided with ArcGIS
Model tools are user-created tools authored using ModelBuilder
Script tools run a geoprocessing Python script file
Geoprocessing tools can be system tools built by Esri and included in ArcGIS products, or custom tools built as script or model tools by you and other users. You can use both custom and system geoprocessing tools in the same ways. Learn more about using geoprocessing in ArcGIS Desktop by taking a quick tour (in the ArcMap documentation).
Use geoprocessing in ArcGIS Runtime
A geoprocessing web service is published from ArcGIS Desktop to ArcGIS Online or ArcGIS Enterprise. This web service and its tasks can be consumed as REST endpoints by web-based clients such as ArcGIS Desktop, ArcGIS Explorer, custom web apps, and ArcGIS Runtime SDK apps.
Learn more about creating and publishing geoprocessing web services.
What is a geoprocessing task?
A geoprocessing task is a REST child resource of a geoprocessing service. A geoprocessing service can host one or more tasks. A task has a set of parameters that define how a client can interact with the task and what kind of input must be passed to it to execute the task. The server executes the task and returns output values to the client. Output values could include a map service to show the results. This allows for the display of complex data and raster data.
The following figure shows the hierarchy of geoprocessing REST resources. Notice that geoprocessing service properties (shown in orange) are inherited by every geoprocessing task. These include the execution type, the maximum number of records to return, and the map service used to return results.
The format for a geoprocessing task URL is http://<gpservice-url>/<taskName>. The endpoint for a task called BufferPoints hosted on myserver, for example, would be the following.
Tasks defined in HTML task pages
The ArcGIS Server service directory contains a set of service pages—web pages of information about each service it provides. You can use the service pages of a geoprocessing service to explore its tasks and their parameters, and learn how to code against them—simply open the REST URL in a browser.
What are task parameters?
Task parameters are the inputs and outputs of a geoprocessing task and vary from task to task based on its individual requirements. Each parameter has a set of properties that describe it, such as name, data type, whether it is required or optional, and so on.
When tasks complete, results are returned in a variety of ways. It’s important to understand how a particular geoprocessing task returns results in order to handle them properly. To learn about parameter types, see geoprocessing task parameters.
A geoprocessing task may output a map service result. This prevents the client app from having to symbolize and draw a large number of features or to try to handle a data format that cannot be added directly to the map via the API. When maps from map services are rendered, symbology is applied to the features.
The work required of a geoprocessing task can be straightforward and may take a few seconds to execute on the server, or it can support advanced functionality—processing large datasets—and may take longer to execute. Therefore, the REST API provides two execution types, which are options for running the geoprocessing task on the server.
- Synchronous: Synchronous tasks are suitable for fast running tasks. In synchronous tasks, the client sends a request to run the task and waits for the results of the task to be returned as a response.
- Asynchronous: Asynchronous tasks are suitable for long running jobs. In asynchronous tasks, the server returns a job ID which the client uses to poll for task status. When the status is completed, the results are created as child resources of the job which the client can access using its job ID.
In ArcGIS Runtime both execution types are accessed asynchronously and the call to the correct REST endpoint is defined by the execution type set on the geoprocessing parameters. Even though the geoprocessing tasks are executed in different manner at the service level, they are accessed through one single API. To learn how you can use geoprocessing in your app, see Run a geoprocessing task.