Multidimensional data in a mosaic dataset
Multidimensional data is captured in multiple times or depths. They are normally stored in netCDF, GRIB, or HDF format. Each file contains one or multiple variables, and each variable is a multidimensional array that represents data in a given time or at a given vertical dimension. For example, a netCDF file can store temperature, humidity, and wind speed for every month from the year 2010 to 2014, and at each elevation of 0, 1 meter, and 10 meters.
The mosaic dataset has always been a data model for managing a collection of images and raster data. Now it has been enhanced to manage multidimensional data and provides a unified data model for working with netCDF, GRIB, and HDF formats. The netCDF, GRIB, and HDF raster types can be used to add data to a mosaic dataset directly without extracting any subdatasets, and the mosaic datasets are multidimensional aware when it is created using the appropriate raster type. You are also able to create a multidimensional mosaic dataset from nonmultidimensional data. See Multidimensional raster types for more information about these raster types.
Besides the common properties that a mosaic dataset has, a multidimensional mosaic dataset has information about the variables, the time dimension, and vertical dimension, which are stored as fields in the mosaic dataset footprint table:
- Variable—The variable name
- Dimensions—The name of the dimensions used in the mosaic dataset
It also contains one or more fields that define the dimensions:
- Standard Time—The standardized time dimension values (UTC)
- Standard Z—The standardized vertical dimension that is measured in length (meter)
- Standard Pressure—The standardized vertical dimension of pressure values (Pa).
The original dimension name and values may be copied to the mosaic dataset. Dimensions defined in other units not on the list will be added directly without normalization. The multidimensional information can be accessed from the Multidimension tab of the Mosaic Dataset Properties.
With the presence of multidimensional properties in the mosaic dataset, ArcGIS Pro can now better visualize and process your multidimensional data. For more information about creating and displaying multidimensional data, see Creating and visualizing a multidimensional mosaic dataset.
Display multidimensional mosaic datasets
The rasters or slices in a multidimensional mosaic dataset are usually stacked slices on top of each other. Filter which slices or variables to visualize using the Time and Processing Templates tabs on a mosaic layer.
Set the time extent, then animate using the time slider. See Visualize temporal data using the time slider for more details.
Use the Processing Templates tab to switch variables for displaying the data. For example, if the mosaic dataset contains two variables, temperature and precipitation rate, make a selection of the processing templates to visualize either variable. In ArcGIS Pro, you can switch between your template using the Processing Templates drop-down arrow in the mosaic layer Data contextual tab.
In ArcGIS Pro 1.4 and later, Explore Raster Items in the mosaic layer Data contextual tab can also be used to explore the multidimensional mosaic dataset, and visualize the preview of single slice and variable. You can even add the preview slice to current map, using the Add button. For more information about the raster item explorer, see Using the Raster Item Explorer.
If a mosaic dataset is created with the vector field template, such as wind or current data, it can be visualized using the Vector Field renderer.
Use a multidimensional mosaic dataset with geoprocessing tools
There are three ways to access a slice or set of slices of a multidimensional mosaic dataset, and use them in geoprocessing tools.
The first method to access your applicable data slices is by using the Make Mosaic Layer tool and specifying a query. For instance, use the Make Mosaic Layertool and specify a query with the month of December 2015, and use the mosaic layer output as an input to the Contour tool, to generate contours of the slice for the month of December 2015.
The second way to access your data slices is by using the Select by Dimension tool to choose the dimension you want to work with.
The third method to access your data slices is to make a selection within ArcGIS Pro, add the selected slices as layers of the map, then you have access to these layers for use within your geoprocessing tools. When you make a selection and add it to your map, you can also choose multiple images to add to map.
If you are trying to calculate the minimum, maximum, or mean from a set of data slices, make the appropriate definition query, then set the mosaic dataset's mosaic operator to be Minimum, Maximum, or Mean. Now you can export the output using the Copy Raster tool.
Analyze and computing new variables on the fly
A raster function templates is an XML file that contains one of a chain of raster functions as well as the corresponding parameters. See Edit processing template properties to learn more about function templates. A scientific formula can be represented by a raster function template.
For example, a wind chill index can be calculated from temperature and wind speed.
wind chill = 35.74 + 0.615T - 35.75*(V^0.16) + 0.4275T*(V^0.16)
This equation can be represented as a raster function template as well. ArcGIS Pro provides the Wind Chill raster function in the Raster Functions pane. Optionally, it can be added through Raster Function Editor.
Publish multidimensional mosaic datasets as image services
An image service is multidimensional if it is published from a multidimensional mosaic dataset. You can access, analyze, and display the data slices the same way you would access the slices in a multidimensional mosaic dataset.
Multidimensional image services support a WMS's time and vertical dimension queries. If you intend to publish an image service that supports standard WMS time and elevation queries, set the fields used for time and vertical dimensions in the mosaic dataset properties before publishing the multidimensional mosaic dataset.
For more information about querying WMS time and vertical dimensions, see Communicating with a WMS service in a web browser.