Run Options

Run Options
Section Name	Control Name	Value
Run Type		This provides two options for the PMP computation: Run once for specified location, which uses a single specified storm center location and a single orientation. Run for selected pattern, which systematically tests multiple storm center locations and orientations within a grid-based spatial search area.
	Run once for specified location	Place the storm center at the same location used to establish the DAD curve. If the DAD selection is based on the basin area, the storm center will be set at the basin centroid.
	Run for selected pattern	Use an iterative search for the location that results in maximum precipitation volume. The initial search iterates through a grid and tests multiple rotations to find one or more local maxima. Next, the program performs a refined search of these local maxima to obtain results at the required precision. The optimization for maximum precipitation volume in HEC-MetVue is different than the optimization for peak elevation of a specific reservoir or peak flow at a defined location which requires the use of HEC-HMS.
Run Once Options		This option provides settings for specifying the storm center location and orientation.
	Compute using same location as DAD curve	If this is selected and the DAD curve location is user-specified, the location the storm is placed at the same location used to compute the DAD curves. Otherwise, the basin centroid will be used. Note that once the storm is positioned at this location it can be moved easily using the HEC-MetVue storm repositioning tools, specifically the rotation and translation tools.
	Use specified position	Select this to place the storm center at a location other than the basin centroid or the selected DAD curve sampling option.
	Rotate storm to align with basin	The default is to align the storm with the basin based on the axis computed by minimizing the 2^nd moment of area about the centroid of the basin. Note that the basin centroid is used for the moment computation regardless of the location that the storm is to be placed. Note that once the storm is positioned at this location it can be moved easily using the HEC-MetVue storm repositioning tools, specifically the rotation and translation tools.
	Specify storm rotation	Select this to manually input a specific storm rotation.
	Storm rotation	This is the azimuth in degrees, measured clockwise from north, of the minimum moment axis (longest radial through the center of the elliptical storm).
	Do not adjust depth for storm orientation	Normally HMR52 requires that the storm intensity be adjusted for storm rotational alignments that differ from the optimal storm alignment. This optimal storm alignment is retrieved from the maps digitized from Figure 8 in the original NOAA HMR52 document. at the same location from which the DAD curves are acquired. If the DAD curves are recomputed for a location, the optimal storm alignment will also be recomputed.
Run For Selected Pattern Options		This option provides settings for distributed computations to optimize the PMP storm orientation, center location, and precipitation volume. HEC-MetVue uses a grid-based spatial search pattern to iterate over the defined search grid point locations to determine the optimal storm orientation and center location that yield the maximum precipitation volume for the basin.
	Simultaneous CPU cores to use	The default the setting is to use all available CPU cores on a computer to speed the analysis. A CPU usage setting lower than the default will constrain HEC-MetVue to use fewer CPU resources and better allow other tasks to run on the computer at the same time.
	Confine search to defined rectangle	The default extents are computed as a rectangle encompassing the input shapefile. Making the constraint rectangle smaller will speed the search with less search grid points to iterate through. The latitude and longitude coordinate inputs must be in decimal degree format.
	Constrain storm rotation iterations to positions	The default is to allow all possible storm alignments, but this option can be used to constrain the major axis of the elliptical storm to the defined range . The degrees are azimuths measured clockwise from north.
	Initial distance increment between trials	This should be set to ensure there are adequate number of trials so that a local maxima is not completely missed. An easy general rule would be to use the forth root of the total area of the shapefile polygons as an upper limit. For example, for a 625 square mile drainage basin would have a distance increment of 5 miles between the initial trial locations.
	Final distance tolerance	This sets the acceptable tolerance for convergence on a final solution for the optimal center of the storm. Once the local maxima locations and alignments for the grid search are complete, a binary search technique is used to settle on the optimal storm center location within the acceptable tolerance.
	Initial rotation increment between trials	For every position on the search grid, the program will iterate through all the rotations possible using this increment interval.
	Final rotation tolerance	Once the best initial rotation value is found for a particular grid point, the rotation will be further refined to the acceptable final tolerance using a binary search approach.
	Only consider maximum from initial search pattern for final positioning	This will only refine the location and rotational alignment for the single grid point where the initial search pattern yields the maximum precipitation volume. For most normally shaped basins, there is usually a single maximum storm location.
	Consider multiple local maxima for output of TINs, hyetographs, etc.	On some basin shapes, there can be more than a single local maximum storm position. This option should especially be used for basins that are oddly shaped such as a horseshoe or boomerang shaped basins, where the centroid of the basin is near or outside of its boundaries. Also, if this option is selected, consider reducing the "Initial distance increment between trials".
	Limit the local maxima count to the top [count] sequences	The default is 10. The likely number of local maxima in normal situations is 1 or 2.