Partnership Shows LiDAR’s Practical Use, Potential in Oregon

A 2.419Mb PDF of this article as it appeared in the magazine complete with images is available by clicking HERE

The Oregon Department of Geology and Mineral Industries (DOGAMI) leads the Oregon LiDAR Consortium, which was created in 2007 with the goal of providing high-quality LiDAR data coverage for the entire state. An initial $2 million seed capital investment by the Oregon Legislature has since been leveraged into more than $15 million of LiDAR acquisition. Projects start with a partner interested in funding a specific area, and DOGAMI then works to enlarge that area by finding additional partners and adding consortium funds to create contiguous blocks of LiDAR collection.

It’s a strategy that’s working, says Jacob Edwards, DOGAMI’s LiDAR project and database coordinator. A recent $951,000 project collected 976 square miles of LiDAR data and orthophotos in the Portland Metro area. The more than 30 partners–including cities, counties, transportation agencies and the U.S. Geological Survey–have access to all the data. They’re putting the LiDAR to many uses, from helping 9-1-1 dispatchers update their information to surveying urban tree canopy to mapping manhole covers.

"With every project, we learn more about the value LiDAR data has for our partners, and for the Pacific Northwest," Edwards says.

Improving understanding of Oregon’s watersheds is a significant use. Using LiDAR imagery, DOGAMI cartographer Mathew Tilman has been working since 2008 to digitize stream centerlines–which are particularly critical in modernizing FEMA’s flood maps, which inform flood mitigation efforts as well as flood insurance requirements. Redrawing the lines digitally is painstaking, detail-oriented work that’s especially intense in Oregon’s highly dendritic Coast Range. But from the first project, he says, it’s been clear how much more accurate the new stream centerlines are.

"We very quickly figured out that what stream data we had was completely wrong," says Tilman, who has now digitized almost 25,000 miles of streams from LiDAR.

Practical application of LiDAR data is ever-expanding. In March 2015, DOGAMI wrapped up a two-year project with the U.S. Forest Service that used LiDAR to map abandoned mine features. A 1860s gold rush followed by sporadic copper, zinc and lead mining left abandoned mine features, including mine entrances, exploration pits and waste rock areas, in Oregon’s North Santiam Mining District. Over time, heavy vegetation obscured signs of mining.

"The mountains are rugged, with thickly forested terrain," says Clark Niewendorp, DOGAMI industrial minerals geologist. "LiDAR offered a clear look."

The maps reveal 226 abandoned mine features where previous mapping showed only 58. Identifying where potential pitfalls are hidden is essential to the work of modern foresters and firefighters, who need to know where mine features are to safely and effectively fight fires and manage forest land.

"LiDAR aids in the inventory and closure of abandoned mine features with the aim to protect public safety," says Ruth Seeger, area minerals geologist for western and central Oregon and western Washington with the U.S. Forest Service. "LiDAR is an effective tool in advance of a ground survey because it increases the efficiency and labor of a time-consuming abandoned mine survey."

Potential uses continue to emerge. A pilot project by the U.S. Bureau of Land Management is looking toward whether LiDAR imagery can be used to map changes to sage grouse habitat over time. LiDAR and orthophotos for a southwest Oregon area ravaged by wildfire were collected in 2013, and the same area is set to be recollected in 2015 in order to analyze tree regrowth.

"As we continue to collect LiDAR within the state we’ll have multiple datasets, and will be able to do more change detection analysis," Edwards says.

Those multiple datasets will be of extreme quality as well. DOGAMI requires aggregate design multi-swath density of at least 8 pulses per square meter. The higher-than-typical density is absolutely necessary, Edwards says, to get accurate bare earth coverage in a state that’s as forested as Oregon. The Agency also has a four-point quality control program in place that stringently reviews specifications for data completeness, swath to swath data consistency, digital elevation model (DEM) requirements, and absolute accuracy of bare earth DEMs.

Since 2008, DOGAMI has ordered 54 large LiDAR flights, supported by funding from more than 60 partners. High-resolution LiDAR data has been acquired for almost 33,000 square miles in Oregon, and approximately 33.5 percent of the state and about 72 percent of Oregon’s populated areas. DOGAMI expects to collect nearly 4,000 additional square miles in 2015. The OLC has also been awarded $770,050 from the U.S. Geological Survey’s 3DEP program, which will help fund a multi-partner project worth nearly $3 million.

LiDAR is the foundation for the Agency’s new generation hazard maps, and geologists are again seeing more revealed than ever before. More landslides have been mapped in the past five years than in the previous 60 years, says DOGAMI Engineering Geologist Bill Burns, and that’s due in large part to LiDAR technology. Almost all of the nearly 20,000 landslides mapped since 2009 have come from geologic and landslide mapping that used LiDAR.

"When we finish mapping with LiDAR for the whole state, we’ll have a very different–and much better– understanding of landslides," Burns says.

Overall, says Interim State Geologist Ian Madin, use of LiDAR data has made DOGAMI far more efficient and effective in performing work over time–and made for astonishingly more accurate, comprehensive maps.

"Before we had LiDAR base maps, we were doing geologic mapping for one or two quadrangles per year," Madin says. "Now we typically map eight per year, with the same resources, and the maps we’re producing are dramatically better.

Ali Ryan is the Earth Science Information Officer for the Oregon Department of Geology and Mineral Industries, known as DOGAMI. She leads the Agency’s efforts to connect Oregonians with information about the Agency’s science and stewardship.

LiDAR Exploration for Pros and the Public

Making LiDAR data easily accessible for both professionals and the public is important. The DOGAMI LiDAR Data Viewer, which launched in 2007, lets casual users explore bare earth digital elevation models of existing Oregon LiDAR data. Users can zoom to 1:9,028 scale for a close look. Comparing LiDAR images to other types of base maps–including satellite and topographic–is also possible. Creating recreation maps, posters, and an annual LiDAR calendar has also expanded general knowledge of LiDAR’s uses–both creative and practical.

Newly added data viewer features are aimed at professional users, who can now click on a quadrangle to purchase LiDAR data. If data are available, a popup will show the USGS top map name and Ohio Code as well as a link to the Nature of the Northwest Information Center to order the data quadrangle. DOGAMI also recently activated a map layer to show where LiDAR is available and where LiDAR is in progress.

Find the DOGAMI LiDAR Data Viewer online:

A 2.419Mb PDF of this article as it appeared in the magazine complete with images is available by clicking HERE

About the Author

Guest Contributors

Guest Contributors ... Articles from Experts in the LiDAR community
Contact Contributor Article List Below