Marblecutter

This is a standalone (Python / Flask) and Lambda-based dynamic tiler for S3-hosted GeoTIFFs. It is also a set of utilities for transcoding and otherwise preparing raster data for rendering by the tiler.

More information:

• Introducing the AWS Lambda Tiler

Development

Development is best done using Docker, as there are a number of dependencies, some of which remain unpackaged for common OSes (e.g. GDAL-2.2+).

If you're going to be experimenting with mosaicking in any form, docker-compose makes things even easier, as it packages marblecutter alongside a PostGIS database containing footprints and other metadata about imagery.

# build
docker-compose build

# start (requires that Postgres has been populated with appropriate footprint data)
docker-compose up

The transcoding and metadata tools can be used from the images built by docker-compose:

docker-compose run web bash
process.sh ...

AWS Lambda / API Gateway

project.json.hbs defines an apex project that can be deployed to AWS Lambda.

Create IAM role: tiler_lambda_function with Trust Relationship policy document:

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Principal": {
        "Service": "lambda.amazonaws.com"
      },
      "Action": "sts:AssumeRole"
    }
  ]
}

Create IAM policy: tiler_lambda_logs with policy document:

{
    "Version": "2012-10-17",
    "Statement": [
        {
            "Action": [
                "logs:*"
            ],
            "Effect": "Allow",
            "Resource": "*"
        }
    ]
}

Attach policy to the tiler_lambda_function role.

Update project.json with tiler_lambda_function's Role ARN, e.g. arn:aws:iam::670261699094:role/tiler_lambda_function.

Run apex deploy. (Add -l debug to see what's running.) This will build the Docker image defined in deps/ to produce a task.zip containing binary dependencies needed when deploying to the Lambda runtime.

Concepts

PixelCollection

A collection of pixels (as data) associated with Bounds.

Bounds

A bounding box (bounds) with an associated CRS (crs).