Ad Hoc Operations

Ad Hoc Operations allows the user to quickly generate time series plot based on points or polygons drawn directly in the Map Window. Plotting point time series from precipitation datasets in HEC-MetVue Map Window can show the temporal variation of the precipitation for the duration of the events.

There are two methods to sample time series from the gridded dataset loaded in a Map Window through the ad hoc operations:  Point Operations and Polygon Operations.

Point Operations

Point Operations allows the user to create time series for a point where the mouse is right-clicked.

  • Select the "MBRFC Precip 1HR" Map Window
  • Allow the data to load. 
  • Zoom into the heaviest precipitation area which fell in the Vermillion, Lower Big Sioux, and the Rock HUC 8s. 
  • Right click the magenta shaded area on the border of the Vermillion and Lower Big Sioux HUC 8s. 
  • Then select the "Ad Hoc Operations" then "Point Operations" then "Plot Time Series for Point ..."
  • HEC-MetVue will begin calculating the time series precipitation for that point.
  • The time series will display in a new window and "Point 1" will appear in the Map Window. 
  • The "Ad Hoc Point Operations" can be repeated to display time series for multiple points in the same Time Series Plot. 

Notice that a time series interval does not have to be specified. HEC-MetVue uses the interval of the dataset to create the time series interval for the plot. This Time Series Plot is showing the precipitation values for a one hour time interval because the Map Window is using hourly grids. 

  • Close the Time Series Plot.

Polygon Operations

  • Select the "MBRFC Precip 1HR" Map Window
  • Select the Draw Tool  to begin creating a polygon within the Rock HUC 8.
  • Create points for the polygon and double left click to finish the polygon. 
  • Right click in the polygon and select "Ad Hoc Operations" then "Polygon Operations" then "Plot Time Series."
  • HEC-MetVue will calculate the time series precipitation for that point and display it in a Time Series Plot window. 
  • Additional polygons can be added to the map using the "Define Polygon" tool and then the "Ad Hoc Polygon Operations" to create the time series.
  • The additional time series will be added to the Time Series Plot window that was created for Polygon 1. 
  • The polygons will be labeled sequentially as they are created and will be assigned different colors.

    Note that a mix of point and polygon time series sampling is possible through the Ad Hoc Operations.

    • Keep the Time Series Plot open. 
    • Add in three point time series to the map window using the "Ad Hoc Operations."
    • Notice that the point time series are added to the polygon Time Series Plot.
    • The polygons and points will be labeled sequentially as they are created and will be assigned different colors.


Question: Which time series of precipitation has the highest value and when did most of the rain occur?

  • Point 1 contains the largest hourly precipitation value of 2.6 inches on July 21st. The time series plot shows that the June flood developed from a three day rainfall event that fell from June 20th through the 22nd. 

Question: From looking a the time series plot, can you narrow down the start and end dates of the precipitation event?

  • The time series shows that the precipitation event of the flood can be assigned a duration of 36-hours from June 20th to June 22nd, 2024.

To remove the "Ad Hoc" polygons and points from the Map Window either remove any particular curve from the Time Series Plot legend or close the Time Series Plot to remove all polygons and points at the same time.

Now that you have explored the general functionality of the ad hoc operations to sample time series from points and polygons, proceed to the next set of tasks to use time series samplings to compare data from different precipitation products.


Tasks

Part A – Introduction to the Project and Datasets

Part B – Ad-Hoc Operations - Time Series

Part C – Mass Processing of Samples