C# Port of the AWS DynamoDB GeoSpatial library

The Geo Library for Amazon DynamoDB enables .NET developers to easily create and query geospatial data. The library takes care of managing the geohash indexes required for fast and efficient execution of location-based queries over a table of items representing points of interest - latitude/longitude pairs.

Along with this library there's a sample application demonstrating usage of the library for a cloud-backed mobile app development scenario. You can get up and running quickly with a local IIS Express application and running the unit tests.

##Features

• Box Queries: Return all of the items that fall within a pair of geo points that define a rectangle as projected onto a sphere.
• Radius Queries: Return all of the items that are within a given radius of a geo point.
• Basic CRUD Operations: Create, retrieve, update, and delete geospatial data items.
• Easy Integration: Adds functionality to the AWS SDK for .NET in your server application.
• Customizable: Access to raw request and result objects from the AWS SDK for .NET.

##Getting Started ###Setup Environment

1. Sign up for AWS - Before you begin, you need an AWS account. Please see the [AWS Account and Credentials][docs-signup] section of the developer guide for information about how to create an AWS account and retrieve your AWS credentials.
2. Minimum .NET requirements - To run the SDK you will need .NET 4.5+.
3. Download Geo Library for Amazon DynamoDB - To download the code from GitHub, simply clone the repository by typing: git clone https://github.com/onovotny/dynamodb-geo-csharp.git.
4. NuGet Package - For use in your applicatin, it's recommended to use the Nuget Package. Run Install-Package DynamoDB.Geo in the package manager console.

##Limitations

###No composite key support Currently, the library does not support composite keys. You may want to add tags such as restaurant, bar, and coffee shop, and search locations of a specific category; however, it is currently not possible. You need to create a table for each tag and store the items separately.

###Queries retrieve all paginated data Although low level DynamoDB Query requests return paginated results, this library automatically pages through the entire result set. When querying a large area with many points, a lot of Read Capacity Units may be consumed.

###More Read Capacity Units The library retrieves candidate Geo points from the cells that intersect the requested bounds. The library then post-processes the candidate data, filtering out the specific points that are outside the requested bounds. Therefore, the consumed Read Capacity Units will be higher than the final results dataset.

###High memory consumption Because all paginated Query results are loaded into memory and processed, it may consume substantial amounts of memory for large datasets.

###The server is essential Because Geo Library calls multiple DynamoDB Query requests and processes the results in memory, it is not suitable for mobile device use. You should maintain a .NET server/Website, and use the library on the server.

###Dataset density limitation The Geohash used in this library is roughly centimeter precision. Therefore, the library is not suitable if your dataset has much higher density.

##Reference

###Amazon DynamoDB

• Amazon DynamoDB
• Amazon DynamoDB Forum