Vaisala IRIS - Composite Algorithm

The remapping feature is important since you may not have control over the range or
resolution of the non-IRIS data. Products from non-IRIS systems can be reformatted to
match the standard IRIS formats and then inserted into IRIS using the Input pipes
mechanism.
Vaisala supplies source code examples to customers who want to reformat non-IRIS data
and insert it into IRIS. These products can then be sent to the composite IRIS workstation
either directly, from an external user program, or through another IRIS.
Composites of Composites (Regional, National/International Composites)
The maximum number of radars that can be used in a composite is 16. This is adequate for
most applications.
For larger networks, it is recommended to first make regional composites, and then
composite the composites to make national or international composites.
5.2.1
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 dierent elevations (for example, 1°) and CAPPI products of
dierent 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.
IRIS Product and Display User Guide M211319EN-H
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