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Open Topography - Infrastructure for Topographic Data

October 05, 2021 6 min read

topographic data, opentopography geospatial and GIS podcast

 

 

Our guest on the podcast today is Christopher Crosby, who is currently the Geodetic Imaging Project Manager for UNAVCO, a geodetic research and education organization that operates the Geodetic Facility for the Advancement of Geoscience. Chris has an extensive background in geoscience, having racked up almost 20 years of experience with LiDAR technology, with a special interest in web-based data delivery systems. Having completed a master’s and PhD in Geoscience with Arizona State University, he began working with the San Diego Supercomputer Center to help bring the OpenTopography project to life. After nearly 10 years, the project has proven to be instrumental to the geospatial and research community, and he will share a little about why that is. 



What is OpenTopography?


OpenTopography is a free online public geospatial data portal, clearinghouse, or spatial data infrastructure (exact terminology is dealer’s choice) for topographic data. Their mission statement is to “Democratize online access to high-resolution (meter to sub-meter scale), Earth science-oriented, topography data acquired with lidar and other technologies.” and to promote interaction, discovery, and knowledge in the Earth science community. 


OpenTopography is primarily funded by the National Science Foundation (NSF)


Their funding is provided with the intent of promoting research and education for all. This takes the form of seemingly limitless open access to topographic data, enabling users to answer the world’s spatial questions. 


The OpenTopography computing infrastructure has been supported by the San Diego Supercomputing Center since its inception and continues to provide backend computing resources that remove the processing burden on the end-user commonly associated with browser-based applications. 


The more technical goal of OpenTopography is to colocate a vast topographic data archive, and the analysis tools needed to accomplish some more common geospatial workflows in the space


The goal of building a holistic data archive has been met with varying success based on locale. More developed countries, such as the United States and European Union member states, have formal topographic data collection efforts geared towards frequent high-resolution collection. 


They have had great success in this area, and quality data collection at regular intervals allows a better understanding of changes in the land through multitemporal data analysis


OpenTopography has leaned into this need for interpreting multitemporal data by providing ready-to-use change detection tools among its analysis options. Other regions, however, may not have the resources to dedicate to high-resolution geospatial data collection, and therefore are more sparsely represented in OpenTopography and less likely to benefit from these kinds of tools for now.   



How is OpenTopography Used?


OpenTopography primarily exists as a topographic data archive, a hub for researchers and educators to go to acquire the data they need to advance their projects. The key here is that access to this raw data alone is hardly ever a user’s objective. They need that data to use as an input to create a product that will help answer their spatial questions.  


OpenTopography enables exactly this by providing on-the-fly analysis tools to create topographic data products, such as digital terrain models (DTMs) and digital surface models (DSMs). Some other DEM derivatives it can provide are slope, and hillshade visualizations. Hillshades can even be exported to kmz for use in Google Maps or Google Earth. 


Elevation data derived from LiDAR collection and more classic collection methods lend themselves to OpenTopography’s TIN (triangulated irregular network) interpolation algorithm. This algorithm serves as the base for generating digital elevation models.

The DEMs lend themselves to hydrologic modeling, and even global solar irradiation products, in addition to the DTMs and DSMs described above.

 

These dynamic spatial products have lent themselves to virtual reality and augmented reality projects, and even video game worlds. 



LiDAR data is essential to OpenTopography’s mission. Increased collection efforts over the years have led to a wealth of point cloud data of ever-increasing quality. The tricky thing about crowdsourced point cloud data is maintaining consistent quality and collection methods.


 Considering LiDAR projects are generally collected on a smaller scale, project-by-project basis, they are particularly challenging to stitch together if coming from a variety of providers


Government-led efforts generally produce the best products as it is easier to enforce standardized workflows and post-processing of data. TheUSGS 3DEP Point Cloud collection is a glowing example of this. The program’s mission is to complete a nationwide collection of LiDAR data by 2023.


OpenTopography has taken this opportunity to advance its mission of democratizing elevation data by providing a convenient catalog for this data, which can ultimately be downloaded through AWS S3 Buckets.   


If this is all a bit too much, don’t worry, OpenTopography is still happy to provide simple browser-based visualization of point clouds and data downloads without all the frills. 




Who Uses OpenTopography?


In the geospatial world there is a bit of a disconnect between the cost of collecting data, versus the cost of hosting that data.


 Data collection is exciting, you launch the drone, satellite, plane, helicopter, hot air balloon, whatever your poison, and return to the ground with a treasure trove of raw data. That data now needs to be cleaned, processed, orthorectified and served. 


A great deal of monetary, and time resources are poured into this, even more than the collection itself. Wouldn’t it be nice if you could access some data that someone already dedicated these resources to? Researchers and scientists have been longing for this for decades, and OpenTopography delivers. 


OpenTopography was created as a sort of topographic data library for academics. Researchers could complete their field collection, then upload the data to the database. When another scientist needs that same data, they can find it in the catalog.


 The beauty of geospatial data is that it is in the eye of the beholder. Data collected with one research intent may be useful for a completely different project


This exchange of knowledge results in unprecedented innovation and ideas, and is very exciting to the National Science Foundation, thus why they continue to fund OpenTopography. 


Considering OpenTopography exists as a public open data portal, many more people than just earth science researchers have made use of this resource.



Educators and students also enjoy open access to topographic data. Additionally, the commercial space has caught on to this bounty. For-profit organizations and companies have been able to take advantage of these resources to further their own projects. 


This is not necessarily a bad thing, but it does place a strain on hosting and serving resources, especially when analysis is conducted at large scales. 


To help mediate this, there is an approval process in place for procurement and processing of very large datasets on the platform, including the USGS 3DEP data. The intent here is to make sure resources are first and foremost being provided to the NSF’s target audience, scientists, researchers, and educators. 


Land Information New Zealand (LINZ) is an excellent case study of how OpenTopography has been able to leverage government partnerships and their open data mandates.


LINZ has undertaken the project of generating LiDAR and high-quality geospatial data for the whole country and making that data available to the public. 


Acknowledging the costs after collection needed to make this happen, they provide funding to OpenTopography in exchange for use of their backend resources to accomplish the data distribution aspect of their mission. OpenTopography gets a suite of high-quality data, and LINZ gets discount hosting, win-win-win. 



What’s Next?

 

With OpenTopography, people come for the data, and stay for the analysis tools (and the data). In order to give the people what they want, OpenTopography will continue to provide access to more data as it becomes available, building out the now iconic elevation data repository. 


Additionally, more data processing tools will be adapted and optimized for browser-based fun, enabling users to reap the benefits of the heavy-hitting processing power of the dedicated resources at the San Diego Supercomputing Center. 


Considering the expense of this computing power, especially when big data analysis comes into play, there may be changes to OpenTopography’s model in the future.


The successful partnership with LINZ has proven promising for future similar endeavours. After 10 years, building sustainability into OpenTopography’s infrastructure is essential in order to continue their mission of democratizing topographic data well into the future. To learn more about how you can help support the project, visit their website, or donate here.  



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