Update documentation

[ghost]

@ianschuler @scisco @KAPPS- @YKCzoli From a satellite imagery newb's perspective, I would like to see a more detailed overview of what this tool can do, such as the following.

Overview: What can landsat-util do?

Landsat-util has three main functions:

• Search for landsat tiles based on several search parameters.
• Download landsat images.
• Image processing and pan sharpening on landsat images.

These three functions can be performed separately or all at once.
Help: Type landsat -h for detailed usage parameters.

Step 1: Search

Search for landsat tiles in a given geographical region, using any of the following:

• Landsat paths and rows: If you know the paths and rows you want to search for.
• Country name: If you know what country you want imagery for.
• Custom shapefile: Use a tool such as http://geojson.io/ to generate custom shapefiles bounding your geographical region of interest. Landsat-util will download tiles within this shapefile.

Additionally filter your search using the following parameters:

• Start and end dates for when imagery was taken
• Maximum percent cloud cover (default is 20%)

Search returns information about all landsat tiles that match your search criteria. This includes a link to an unprocessed preview of the tile. The most important thing is the tile's sceneID, which you will need to download the tile (see step 2 below).

Examples of search: Search by path and row: $: landsat search --cloud 6 --start "july 01 2014" --end "august 1 2014" pr 165 100

Search by country: $: landsat search --cloud 6 --start "july 01 2014" --end "august 1 2014" country 'Singapore'

Search by custom shapefile: $: landsat search --cloud 6 --start "july 01 2014" --end "august 1 2014" shapefile path/to/shapefile.shp

Step 2: Download

You can download tiles using their unique sceneID, which you get from landsat search.

Examples of download: Download images by their custom sceneID, which you get from landsat search: $: landsat download LC80030032014142LGN00 LC80030032014158LGN00

Search and download tiles all at once with the --download flag: $: landsat search --download --cloud 6 --start "july 01 2014" --end "august 1 2014" pr 165 100

Step 3: Image processing

You can process your downloaded tiles with our custom image processing algorithms. In addition, you can choose to pansharpen your images.

Examples of image processing: Process images that are already downloaded. Remember, the program only accepts zip files: $: landsat process path/to/LC80030032014158LGN00.tar.bz

Process and pansharpen a downloaded image: $: landsat process --pansharpen path/to/LC80030032014158LGN00.tar.bz

Search, download, and process images all at once using the --imageprocess flag: $: landsat search --imageprocess --cloud 6 --start "july 01 2014" --end "august 1 2014" shapefile path/to/shapefile.shp

[scisco]

@millerEric Excellent. Could you update the readme and send a pull request?