cardboard

Cardboard is a JavaScript library for managing the storage of GeoJSON features on an AWS backend. It relies on DynamoDB for indexing and small-feature storage, and S3 for large-feature storage. Cardboard provides functions to create, read, update, and delete single features or in batch, as well as simple bounding-box spatial query capabilities.

Installation

npm install cardboard
# or globally
npm install -g cardboard

Configuration

Generate a client by passing the following configuration options to cardboard:

option | required | description --- | --- | --- mainTable | X | the name of the DynamoDB table to use region | X | the region containing the given DynamoDB table accessKeyId | | AWS credentials secretAccessKey | | AWS credentials sessionToken | | AWS credentials dyno | | a pre-configured dyno client to use for DynamoDB interactions

Providing AWS credentials is optional. Cardboard depends on the AWS SDK for JavaScript, and so credentials can be provided in any way supported by that library. See configuring the SDK in Node.js for more configuration options.

If you provide a preconfigured dyno client, you do not need to specify table and region when initializing cardboard.

Example

var Cardboard = require('cardboard');
var cardboard = Cardboard({
    mainTable: 'my-cardboard-table',
    region: 'us-east-1',
});- '6.9'

Creating a Cardboard table

Once you've initialized the client, you can use it to create a table for you:

cardboard.createTable(callback);

You don't have to create the table each time; you can provide the name of a pre-existing table to your configuration options to use that table.

API documentation

See api.md.

Concepts

Datasets

Most cardboard functions require you to specify a dataset. This is a way of grouping sets of features within a single Cardboard table. It is similar in concept to "layers" in many other GIS systems, but there are no restrictions on the types of features that can be associated with each other in a single dataset. Each feature managed by cardboard can only belong to one dataset.

Identifiers

Features within a single dataset must each have a unique id. Cardboard uses a GeoJSON feature's top-level id property to determine and persist the feature's identifier. If you provide a cardboard function with a GeoJSON feature that does not have an id property, it will assign one for you, otherwise, it will use the id that you provide. Be aware that inserting two features to a single dataset with the same id value will result in only the last feature being persisted in cardboard.

Collections

Whenever dealing with individual GeoJSON features, cardboard will expect or return a GeoJSON object of type Feature. In batch situations, or in any request that returns multiple features, cardboard will expect/return a FeatureCollection.

Precision

Cardboard retains the precision of a feature's coordinates to six decimal places.