rio-l8qa 0.1.0

CLI and python module for working with Landsat 8 QA band

# rio-l8qa

Landsat 8 QA band CLI tool and python module

## Install

```
$ pip install rio-l8qa
```


## Python Usage

The `l8qa` module provides both `qa` (for Landsat Collection 1 data) and `qa_pre` (for pre-Collection landsat data). Both provide a number of functions to extract integer data from the respective QA band formats.

* cirrus_confidence
* cloud
* cloud_confidence
* cloud_shadow_confidence
* fill_qa
* lookup
* radiometric_qa
* snow_ice_confidence
* terrain_qa

And some additional utilty functions to calculate stats or write cloud masks.

* summary_stats
* write_cloud_mask

#### Example

```
from l8qa.qa import cloud_confidence
import rasterio

qatif = "LC08_L1TP_005004_20170410_20170414_01_T1_BQA.TIF"

with rasterio.open(qatif) as src:
yesclouds = cloud_confidence(src.read(1)) == 3 # high confidence
```

## Command Line Usage

*The command line interface currently works only with new Landsat collections format. See `docs/collections.md` for details.*

Summary statistics for each of the QA metrics

```
$ rio l8qa LC08_L1TP_005004_20170410_20170414_01_T1_BQA.TIF \
--stats
{
"cloudConf": {
"maybe": 0.000119,
"yes": 5e-06,
"no": 0.486637,
"notDetermined": 0.513239
},
...
}
```

To generate output tifs for each QA metric to a directory
```
$ rio l8qa LC08_L1TP_005004_20170410_20170414_01_T1_BQA.TIF \
--outdir /tmp
$ ls /tmp
/tmp/LC08_L1TP_005004_20170410_20170414_01_T1_cirrusConf.TIF
/tmp/LC08_L1TP_005004_20170410_20170414_01_T1_cloud.TIF
/tmp/LC08_L1TP_005004_20170410_20170414_01_T1_cloudConf.TIF
/tmp/LC08_L1TP_005004_20170410_20170414_01_T1_cloudShadowConf.TIF
/tmp/LC08_L1TP_005004_20170410_20170414_01_T1_fill.TIF
/tmp/LC08_L1TP_005004_20170410_20170414_01_T1_radiometricSaturation.TIF
/tmp/LC08_L1TP_005004_20170410_20170414_01_T1_snowIceConf.TIF
/tmp/LC08_L1TP_005004_20170410_20170414_01_T1_terrain.TIF
```

If you need a uint8 0-255 cloud mask, suitable for use as an alpha band in an RGBA geotif, there is a shortcut
```
$ rio l8qa LC08_L1TP_005004_20170410_20170414_01_T1_BQA.TIF \
--cloudmask /tmp/justclouds.tif
```