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An overview of multidimensional data in a mosaic dataset

Multidimensional data in a mosaic dataset

Multidimensional data is captured in multiple times or depths, and is often 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 2019, and at each elevation of 0, 1 meter, and 10 meters.

The mosaic dataset is a data model for managing a collection of images and raster data, including multidimensional data, and it 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 dataset is multidimensional-aware when it is created using the appropriate raster type. You can also create a multidimensional mosaic dataset from imagery collected over time or at different heights or depths. For example, you can create a multidimensional mosaic dataset with NDVI data created from Landsat images collected over multiple years. See Multidimensional raster types for more information.

Besides having the common properties of a mosaic dataset, a multidimensional mosaic dataset has information about the variables and dimensions that are stored as fields in the mosaic dataset footprint table:

  • Variable—The variable name
  • Dimensions—The names of the dimensions used in the mosaic dataset

There are two ways to create a mosaic dataset that is multidimensional-aware. You can create a mosaic dataset and add rasters using the netCDF, HDF or GRIB raster type, which will import dimension and variable information into the mosaic dataset and generate the Multidimensional Info tab in the Mosaic Dataset Properties dialog box. Alternatively, you can use the Build Multidimensional Info tool to generate the required multidimensional fields, metadata, and structure to make the mosaic dataset multidimensional-aware. You must have a field in your mosaic dataset footprint table that identifies the variable in each raster, and there must be a time or height field in the footprint table to define one or more dimensions.

With the presence of multidimensional properties in the mosaic dataset, you can visualize and process your multidimensional data. For more information about displaying multidimensional data, see Visualize 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.

Time tab for Layer properties

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.

Processing templates for Layer properties

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.

Contour model

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.

Add selection 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.

Resolve overlap = Mean

Analyze and compute new variables on the fly

A raster function template is an XML file that contains one of a chain of raster functions as well as the corresponding parameters. See Raster function 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.

Wind chill model

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.

Use Time

For more information about querying WMS time and vertical dimensions, see Communicating with a WMS service in a web browser.

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