HTM Implementation

Requirements

Tested Platforms

Intersection Benchmarks

Documentation

Download

Requirements

The HTM Implementation has evolved a lot over the past few years. Initially, Alex Szalay put together the first C code that generated the complete HTM index and was able to perform most of the querying. Robert Brunner wrote the first C++ version, calling it AstroMap. When we first started to receive 'real' data in 1998, we gathered enough experience to know where the bottlenecks lie. The code was completely redesigned and rewritten in C++ by Peter Kunszt in 1999, based on the initial C implementation, improving the performance by factors up to 300. With the new implementation, we can in principle go down to any level depth, although the current maximum level is set to 14. All known bugs have been resolved, and new functionalities have been added for complex query handling. The current version is 2.0. Here are some benchmarks.

The code should work on every computer with a C/C++ compiler or with JDK1.2 installed for the java version. It has been successfully tested on these platforms.

There are 3 APIs available:



C bindings


C++ set of classesDocumentation / Papers


a Java2 package


Documentation

There are online documentations available:

C functions


C++ classes and methods


Java class documentation (JavaDoc)


Detailed description


Download

The HTM code that can be downloaded here has the following functionality:


• For a given point (x,y,z) on the sphere, return the node name it belongs to up to a given level
• For a given node name, return the 3 vertex vectors
• Bit-encode and decode node name into an integer
• Supports complicated query surfaces on the sphere, returning the node names for each node fully contained in the query surface and for each node partially contained in the query surface
• Visualization in Java3D (only available in the Java package)

The documentation is included with each package. If you are interested in very detailed descriptions of the HTM, please read one of the publications or see the online details.

NOTE: To download - depending on your browser settings - you might have to hold the shift key while clicking on the link you're interested in.

C bindigs

C functions and documentation, in .tar.gz for unix


C functions and documentation, in .zip for windows


C documentation only (HTML), in .tar.gz for unix


C documentation only (HTML), in .zip for windows


C++ classes

C++ classes and doc, in .tar.gz for unix (75K)


C++ classes and doc, in .zip for windows, as a VisualC++ 6.0 workspace (106K)


C++ class documentation only (HTML), in .tar.gz (20K)


C++ class documentation only (HTML), in .zip (27K)


Java package

Java htm package htmIndex.jar with examples and a 3D visualization tool (107K)


Java HTML documentation in .tar.gz format for Unix (56K)


Java HTML documentation in .zip format for Windows (160K)

Peter Z. Kunszt,
Last Modified: October 18, 1999.