Terrestrial imagery combined with structure-from-motion (SfM) provides a relatively easy-to-implement method for monitoring cryospheric systems, even in remote and rough terrain. The collection of in-situ data and identification of control points required for orientation in SfM processing is the primary roadblock to using SfM in difficult to access locations; it is also the primary bottleneck for using SfM in a time series. Recently, other studies have presented different automated approaches to SfM processing with time lapse imagery, but most approaches still rely on control points for georeferencing. We set out to develop an approach to 4D change detection using time lapse imagery which eliminated the need for surveying and identifying control points.
This software implements a new, semi-automated approach for georeferencing terrestrial point clouds (TPC) using a reference point cloud (e.g. aerial point cloud; RPC). We utilize a Discrete Global Grid System (DGGS; Hall et al., 2020) which allows us to capitalize on easily collected information about camera deployment to coarsely register the TPC, and provides a natural correspondence between the TPC and RPC. The approach requires minimal interaction in a user-friendly interface, while allowing for user inspection of results.
Hall J, Wecker L, Ulmer B, Samavati F. [Disdyakis Triacontahedron DGGS]. ISPRS Int’l J. of Geo-Information. 2020; 9(5):315.
- Load point clouds in both referenced and unreferenced frames
- Select the viewpoint of the cameras used to create the unrefereneced cloud
- Automatically optimize fit between reference data and unreferenced point cloud
- Inspect results and select the best solution for further refinement
- Apply results to a time series of point clouds that share the same view
GeoShpr is currently available as a downloadable binary for Windows only. We are working on Linux and OSX versions, as well as the software open source.
To install download the two zip folders into one directory and extract the contents. In the geoshpr-vX folder, find the sandbox.ini file and open it with a text editor. Change the directory path to point to the geoshpr-data folder you just extracted.
That's it! Now open the geoshpr executable and start georeferencing!
One known issue during installation is an incompatability with some native Windows graphics cards. If the software fails to open, try changing the preferred graphics card under in the control panel.
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Load Select the reference data and input camera locations in the reference coordinate frame. Then select the unreferenced point cloud an dinptu the camera loations in the relative frame of the point cloud. Data scenarios can be saved and reloaded in JSON format.
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Orient Select the midpoint of the unreferenced data and adjust the uncertainty of your selection. This highlights the cells searched for best fit in step 4.
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Scale - currently the scaling is not optimized in the software
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Optimize Automatically optimize the best fit between the reference data and the unreferenced data. Solutions are sorted based on the fit and the user can then inspect each solution to choose the best one.
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ICP - an internal fine-registration step is not implemented yet
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Apply Apply the selected solution to any set of selected point cloud files.
Watch the tutorials in the Figures sub-directory to learn more about using the software.
The zip files above contain a sample scenario using data from Fountain Glacier, Nunavut, Canada. The reference data is a point cloud reconstructed from a July 1, 2010 remotely piloted vehicle flight. The unreferenced data was created from two terrestrial images images overlooking a dry calving front on the north side of the glacier. Both point clouds were downsampled for computational efficiency. Data license information is found in the data directory.
GeoShpr was designed and conceptualized by Eleanor Bash (Postdoctoral Fellow, University of Waterloo), Lakin Wecker (PhD Candidate, University of Calgary), and Mustafizur Rahman (Research Associate, University of Calgary). This was originally presented at the American Geophysical Union Annual Meeting in 2021.
Work was supported by the Applied Geospatial Research Group, UW Glaciology, NSERC, and Graphics, Interaction, and Visualization Group.
Development of this software is ongoing, please submit feature requests and bug reports to help us improve it!
(c) 2018-2021 Lakin Wecker & Faramarz Samavati
Permissive Binary License
Version 1.0, September 2015
Redistribution. Redistribution and use in binary form, without modification, are permitted provided that the following conditions are met:
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Redistributions must reproduce the above copyright notice and the following disclaimer in the documentation and/or other materials provided with the distribution.
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Unless to the extent explicitly permitted by law, no reverse engineering, decompilation, or disassembly of this software is permitted.
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Redistribution as part of a software development kit must include the accompanying file named "DEPENDENCIES" and any dependencies listed in that file.
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The following open source projects are either used directly within the the above source or were used during its development.
- boost/1.76.0 - https://github.com/boostorg - https://www.boost.org/ - Boost License
- eigen/3.3.9 - https://eigen.tuxfamily.org/index.php?title=Main_Page - MPL2 License
- fmt/7.1.3 - https://github.com/fmtlib/fmt - LICENSE
- gdal/3.3.1 - https://gdal.org/ - MIT/X license
- glfw/3.3.3 - https://www.glfw.org/ - zlib/libpng license
- hdf5/1.12.0 - https://portal.hdfgroup.org/display/HDF5/HDF5 - BSD-3 License
- imgui/1.81 - https://github.com/ocornut/imgui - MIT License
- immer - https://github.com/arximboldi/immer - Boost License
- implot - https://github.com/epezent/implot - MIT License
- lager - https://github.com/arximboldi/lager.git - MIT License
- libgeotiff/1.7.0 - https://github.com/OSGeo/libgeotiff - X-Style
- libigl - https://github.com/libigl/libigl - MPL2 License
- ms-gsl/3.1.0 - https://github.com/microsoft/GSL - MIT License
- nlohmann_json/3.9.1 - https://github.com/nlohmann/json - MIT License
- openssl/1.1.1k - https://github.com/openssl/openssl - Apache 2.0 License
- pdal/2.3.0 - https://pdal.io/ - BSD
- portable-file-dialogs - https://github.com/samhocevar/portable-file-dialogs - WTFPL License
- proj/8.1.1 - https://proj.org/ - X/MIT License
- range-v3 - https://github.com/ericniebler/range-v3 - Boost License
- spdlog/1.8.2 - https://github.com/gabime/spdlog - MIT License
- tbb/2020.3 - https://github.com/oneapi-src/oneTBB - Apache 2.0 License
- tinyply/2.3.2 - https://github.com/ddiakopoulos/tinyply - Public Domain
- vivid - https://github.com/gurki/vivid - MIT License
- zstd/1.4.5 - https://github.com/facebook/zstd - BSD-3 License
- zug - https://github.com/arximboldi/zug - Boost License