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A file format and library for storing and rapidly accessing point
cloud data, in particular LIDAR data.
GeoHashTree organizes points into a tree structure for fast spatial
access. The tree structure itself encodes the significant bits of
at each node, so child nodes can omit them. The result is a smaller
file than if all the points were stored with full precision. Each
node includes statistical information about the children below (e.g.
average/median Z value) permitting fast overview generation.
Additional attributes are attached to the tree at parent nodes,
below which all children share the attribute value. This reduces
duplicate data storage further.
The advantage of a GeoHashTree file over a LAS file is fast access
and filtering, since the tree encodes useful information at each
node to speed searches over the full set of points in the file.
LASZ zipped files can be smaller, but will be less efficient at
overviews, searching and sub-setting. GHT is a good working format
for applications that will be filtering and querying large sets of
LIDAR data.
WWW: https://github.com/pramsey/libght
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