LAR - Log Amplitude Ratio
- Hook Hua
- Shi Tong Chin
slcp2pm (LAR)
SLC Pair to Log Amplitude Ratio
This repository contains jobs to convert S1-SLCP products to Log Amplitude Ratios (LARs) for creating Flood Proxy Maps v1 (FPMv1).
A LAR is created based on the below pairing system, using 2 SLCs --> 1 SLCP --> 1 FPM:
Note: Since SLCP:LAR is 1:1, the pairing of SLCPs is not required to make LARs. Hence, user simply needs to facet on target SLCPs to execute the LAR job on.
Job 1: S1 Log Amplitude Ratio
Type: Iterative
Facet: SLCPs to create LARs from
User inputs:
Fields | Description | Type | Example |
|---|---|---|---|
| Range looks to create LARs. (Overrides looks in SLCP's metadata) | int | 7 |
| Azimuth looks to create LARs. (Overrides looks in SLCP's metadata) | int | 2 |
Important outputs:
Product | Description | Example |
|---|---|---|
Log Amplitude Ratio Products | Geocoded, multilooked LARs | logr_[burst][range_lks][az_lks].float.geo |
Amplitude Products | Geocoded, multilooked amplitudes stored in 2 bands. Band 1 - Master scene's amp. Band 2 - Slave scene's amp. | amp_[subswath][range_lks][az_lks].amp.geo |
Notes on S1 Log Amplitude Ratio
The LARs in this PGE are computed as such (from log_ratio.py):
(Latest) From dataset
v2.0onwards:
where A = Amplitudes of SLCs of the given date in the co-registered SLCPs
=> Negative values / darker pixels correspond to decreased amplitudes in the post-event scene and possible open-water flood.
Before dataset
v2.0(v1.xetc):
where A = Amplitudes of SLCs of the given date in the co-registered SLCPs
=> Positive values / brighter pixels correspond to decreased amplitudes in the post-event scene and possible open-water flood.
(Below section was moved from hysds-core wiki https://hysds-core.atlassian.net/wiki/spaces/HYS/pages/28540951/Product+Generation)
How to Generate LAR Products
Facet on the SLCP's from which LAR products will be generated.
Click the On-Demand button to bring the action parameters modal up.
Select the S1 Log Amplitude Ratio action. Default parameters are shown.
Enter a tag.
Select the priority and queue for the job.
Click the Process Now button to submit the job that will create the LAR products.