Overview

The GeoModelGrids project focuses on storing and querying georeferenced raster-based models with an emphasis on regional models. The models are composed of blocks, in which each block is a grid with a potentially different resolution that vary along the x, y, or z axis.

Motivation

• Support variable resolution models that include topography and are in any standard geographic projection.

• Support querying for model values on a wide range of platforms, from laptops and desktops to large clusters.

Features

• Store models using a self-describing, portable, widely-used storage scheme, HDF5.

• Models are composed of an arbitrary number of vertically stacked blocks of uniform or variable resolution.

• Models domains may be in wide variety of georeferenced coordinate systems and need not be aligned with the x and y axes of the geographic projection.

• If the model includes topography, the blocks will be warped to conform to the ground surface. Queries for applications requiring a flat top surface can use “squashing” relative to either the top surface of the of the model or topography/bathymetry (if provided).

• In serial queries (intended for use on laptops and desktops), only a portion of the model is loaded into memory, thereby allowing queries of models that are much larger than the available memory.

• In addition to discretization information, the self-describing format includes description of the names of the values and their units, and coordinate system information.

Use Cases

There are many possible use cases. Our first target use case is storing and querying 3D seismic velocity models for simulation and analysis of earthquake ground motions.