Composite Algorithm

Basic Rules

COMP takes products from several radar sites and combines them into a single product using the following rules:

  • The input products must be of the same type (for example, CAPPI) and have the same name.

    This is the recommended way to manage products on your network in general.

    Note that IRIS sorts everything by site for you, so there is no need to put a site ID in the name.

    The product type and name are specified in the COMP Product Configuration Menu.

  • The products must be within a certain time window to be combined.

    You would not want to combine data if the input products were more than a few minutes apart.

    The time window is specified in the COMP Product Configuration Menu.

Remapping

The products to be composited are remapped to the common projection that is specified in the COMP Product Configuration Menu.

Ideally, PPIs and CAPPIs should be at the same elevation angles and heights.

If they are not at the same elevation angles and heights, there are tolerances for combining PPI products of slightly different elevations (for example, 1°) and CAPPI products of different heights (1000 m (3280 ft 10 in)).

Combining

For regions where radars overlap, you can select one of the following methods for combining radar data:

  • Maximum

    Maximum uses the maximum value to combine the data. This is the most common setting.

  • Average

    Average uses the average of the available data. This is a poor choice if you are trying to cover blocked regions.

  • Priority

    Priority uses data from the available radar that is highest on the site list defined in the COMP Product Configuration Menu.

  • Nearest

    Nearest uses data from the radar that is at the shortest distance away. The data from the radar that is further away is ignored.

  • Weighted

    For weighted, the assigned value at a location is determined by a weighted average from all the radars detecting a signal at that location.

    The weighting is inversely proportional of the distance to the radar site. Data from closer radar sites have a bigger impact to the final value than data from sites farther away.

You can choose the combining algorithm in the COMP Product Configuration Menu.

Output

There is no COMP product. The output of a COMP PPI is a PPI product with the name that is assigned in the COMP Product Configuration Menu.