While spatial analysis is a broad term that encompasses a variety of operations available in ArcGIS Maps SDK for Swift, this chapter describes the high-performance and exploratory analysis APIs, which provide classes and members to perform analysis
Examples of high-performance spatial analysis include:
- identifying gaps in security camera coverage to determine where to place additional cameras (viewshed analysis)
- confirming that tourists have a clear line of sight between an observation deck and several landmarks (line of sight analysis)
- performing calculations on bands of multispectral raster data to derive new datasets, such as vegetation indices (map algebra operations)
Analysis options
A variety of spatial analyses can be performed using the analysis APIs. Analysis results can be visualized interactively in a scene view
As an alternative to high-performance and exploratory (GPU-based) analysis, you can use geoprocessing
Analysis accuracy and results persistence
For high-precision analysis in 2D or 3D, use the functionality exposed by the following classes: ViewshedFunction, LineOfSightFunction, DiscreteFieldFunction, ContinuousFieldFunction, and BooleanFieldFunction. This API operates on the underlying data directly, independent of the current view display, and produces results that can be persisted for later use. The data used for these analyses comes from a ContinuousField, DiscreteField, or BooleanField, representing the set of values in an input dataset.
Conversely, the exploratory analysis functionality exposed by ExploratoryViewshed and ExploratoryLineOfSight operate on the 3D surface, layers, and objects currently visible in a scene view. The accuracy of their calculations is based on the current level of detail, which can vary based on the scene view’s camera position and graphics hardware specifications. Because this analysis relies on the 3D display of objects in a scene view, it cannot be implemented in a map view. The results created by these classes cannot be persisted.
The following table summarizes the capabilities of the various spatial analysis tools available in the API.
- Analysis is based on a single terrain dataset rather than the contents of a map or scene view. The terrain dataset may include buildings and other 3D objects.
- If results are calculated in WGS 84.
- Uses any number of raster datasets required for the analysis.
- Accuracy varies according to the scale at which the data is displayed.
