AHTSE
Apache HTTPD Tile Server Ecosystem
AHTSE is a collection of Apache httpd modules that can be used independently or combined to implement high performance and scalable tile services. While developed for geospatial applications, AHTSE can be used in other domains that need fast pan and zoom access to large datasets. The main AHTSE common feature that provides interoperability is the tile request format. The tile request supported by ATHSE is a REST request which ends with four integer values, path encoded as "tile/M/Level/Row/Column", called an MLRC tile address. The Level - Row - Column values are the usual tile and pyramid addressing values, while M is a server defined, multi-purpose value, exposing one or more extra dimensions of the served dataset. The M parameter is the only optional one, it defaults to zero when only three numerical parametes are available at the end of the URL.
AHTSE Components
| Type | Name | Function |
|---|---|---|
| Common | AHTSE | Top level AHTSE project, contains useful scripts to build AHTSE |
| libahtse | common code, shared by AHTSE modules | |
| libicd | Raster format codecs with uniform access API | |
| Sources | mrf | Serves tiles from an MRF file |
| ecache | Serves tiles from an esri bundle cache, also cache other tile services | |
| fractal | INCOMPLETE Generates tiles of a fractal as a test source | |
| Transformations | retile | Projection, tile grid and scale, format change |
| convert | Data values and type conversions | |
| fillin | Fill in missing tiles by oversampling lower resolution levels. It can be used to fill in sparse datasets, or to add oversampled levels. | |
| pngmod | PNG manipulation module, without a full transcode | |
| Protocol | twms | Converts requests from tWMS protocol to AHTSE style |
| Utilities | receive | Subrequest filter that enables passing tile data between AHTSE components |
| conditonal send file | Used for protocol handshake files, it responds with the content from a static file to requests matching specific patterns | |
| brunsli | Filter to convert between JPEG JFIF and brunsli on the fly | |
| lua | Allows AHTSE modules to be extended with Lua scripts |
Getting Started
This repository contains a few bash scripts that can be used to build most of the AHTSE components on an Amazon Linux instance. bootstrap.bash is the main build script