Create Multidimensional Raster Mosaic

Summary

Create Multidimensional Raster Mosaic creates a multidimensional raster mosaic dataset from the NetCDF raster files output by Run Cases on Azure and returned from Microsoft Azure® by the Download Cases from Azure tool.

To learn more about the Liquids HCA Tool in general, please see Liquids HCA Tool Frequently Asked Questions.

To learn more about the structure of the Liquids HCA Tool project geodatabase, please see Liquids HCA Tool Data Dictionary.

Usage

Each GeoClaw case processed on Microsoft Azure via Run Cases on Azure results in a NetCDF format multidimensional raster data file. Although you can create individual multidimensional raster layers from individual NetCDF files, a more useful way to view the output from Run Cases on Azure is to create a multidimensional raster mosaic dataset that allows you to visualize all of your release point product plumes at once. Although you can generate a multidimensional raster mosaic dataset manually by using several ArcGIS geoprocessing tools in succession, Create Multidimensional Raster Mosaic offers you a handy way to do the same thing using a single geoprocessing tool.

Create Multidimensional Raster Mosaic utilizes the following parameters:

  • Working Directory – This must be the same working directory that you used in running Create GeoClaw Cases, Run Cases on Azure, and Download Cases from Azure. The plume simulation NetCDF files used to construct the output multidimensional raster mosaic dataset are stored in your Liquids HCA project working directory under their corresponding GeoClaw case folders.
  • Output Location – This is the path to the geodatabase that will store the output multidimensional raster mosaic dataset. Note that the output multidimensional raster mosaic dataset is a composite data object; it consists of the output multidimensional raster mosaic dataset in the host geodatabase plus all the referenced NetCDF files. If you move your Liquids HCA project working directory, you will have to reset the data path links in your multidimensional raster mosaic dataset. For this reason, it’s a good idea to keep the host geodatabase and the underlying NetCDF files near each other. The default output location is the scratch geodatabase for the active ArcGIS Pro project, but it’s recommended that you store your multidimensional raster mosaic dataset in your Liquids HCA project geodatabase.
  • Mosaic Dataset Name – This is the name of the multidimensional raster mosaic dataset that you are creating. The default name is MultiDimRasterMosaic. You may name your multidimensional raster mosaic dataset as you wish, subject to the naming conventions of the host geodatabase. For example, your multidimensional raster mosaic dataset name cannot start with a number.
  • Coordinate System – This is the coordinate system for your output multidimensional raster mosaic dataset. The default projection is WGS_1984_Web_Mercator_Auxiliary_Sphere, which is the native projection of your NetCDF format release point plume simulation files.
  • Statistics Skip Factor – This is the pixel sampling frequency (in both the horizontal and vertical directions) used to examine your NetCDF files for purposes of calculating raster statistics. The default value of 1 means that every pixel in every NetCDF file will be examined to calculate statistics. A value of 2 means every other pixel row and column will be examined; 3 means every third pixel row and column, and so on.

Bear in mind that each time slice in each NetCDF file corresponds to an individual image in the output multidimensional raster mosaic dataset. Assuming an 8-hour simulation and a 2-minute time slice interval, each of your NetCDF files results in 241 images in the output multidimensional raster mosaic dataset. For large numbers of release points, statistics calculations can be very time consuming. For large numbers of release points, you should consider using a large skip factor.

  • Enable Pixel Cache – This checkbox parameter determines whether a pixel cache will be created for your output multidimensional raster mosaic dataset. This parameter is disabled by default. While a pixel cache will improve display performance, understand that each time slice in each NetCDF file results in a separate pixel cache file. One thousand release points with an 8-hour simulation and a 2-minute time slice interval would result in 241,000 individual pixel cache files. Such large numbers of files can cause problems with operating system file systems, particularly in cases where backups and virus scans are being performed. Use pixel caches with caution.
  • Pixel Cache Location – This parameter is visible only when the pixel cache parameter is enabled. This is the directory in which the pixel cache files will be stored. Pixel cache files are stored in the scratch workspace for the active ArcGIS Pro project by default. However, you may want to designate your Liquids HCA project working directory as the destination for your output pixel cache files, to keep them together with your GeoClaw case folders.

In a typical Liquids HCA workflow, Create Multidimensional Raster Mosaic is run after Download Cases from Azure.

For visual reference on Liquids HCA Tool execution order, see Liquids HCA Tool Process Flow Diagrams.

Syntax

CreateMultiDimRasterMosaic_ (input_data, working_dir, mosaic_dataset, coordinate_system, xy_skip_factor, enable_pixel_cache, {pixel_cache_location})

Parameter Explanation Data Type
input_data

Dialog Reference

Specify the working directory storing your release point case folders (and the NetCDF plume simulation files contained therein).

There is no Python reference for this parameter.

Workspace
working_dir

Dialog Reference

Specify the path to the geodatabase that will store the output multidimensional raster mosaic dataset.

There is no Python reference for this parameter.

Workspace
mosaic_dataset

Dialog Reference

Specify the name of the output multidimensional raster mosaic dataset.

There is no Python reference for this parameter.

String
coordinate_system

Dialog Reference

Specify the spatial reference system of the output multidimensional raster mosaic dataset.

There is no Python reference for this parameter.

Coordinate System
xy_skip_factor

Dialog Reference

Specify the pixel skip factor to use in calculating raster statistics for the output multidimensional raster mosaic dataset.

There is no Python reference for this parameter.

Long
enable_pixel_cache

Dialog Reference

Check the checkbox to enable a pixel cache for the output multidimensional raster mosaic dataset.

There is no Python reference for this parameter.

Boolean

pixel_cache_location

(Optional)

Dialog Reference

Specify the output workspace for your multidimensional raster mosaic dataset pixel cache files.

There is no Python reference for this parameter.

Workspace

Code sample

The following script demonstrates how to use Create Multidimensional Raster Mosaic in Python:

import arcpy
arcpy.ImportToolbox(r”C:\Program Files\ArcGIS\Pro\bin\Python\envs\arcgispro-py3\Lib\site-packages\liquidshca\esri\toolboxes\LiquidsHCA.pyt”)
in_dir = r”C:\data”
in_gdb = r”C:\data\test.gdb”
mosaic_raster = “MultiDimRasterMosaic”
spacial_ref = arcpy.SpatialReference(3857)
skip_factor = 1
pix_cache = False
arcpy.liquidshca.CreateMultiDimRasterMosaic(in_dir, in_gdb, mosaic_raster, spacial_ref, skip_factor, pix_cache)

Environments

Current Workspace, Scratch Workspace, Raster Statistics

Licensing information

This tool requires a valid Liquids HCA Tool user license or subscription. Please see the Request License and Register License tool help topics for details on obtaining and registering a Gas HCA Tool software license.

Related topics

Tags

Liquids HCA, NetCDF, Raster, Mosaic Dataset, Statistics, Multidimensional, Raster Mosaic.

Credits

Copyright © 2003-2020 by G2 Integrated Solutions, LLC. All Rights Reserved.

Use limitations

There are no access and use limitations for this item.