Over the past several years, the DNR began mapping the state using LiDAR, a state-of-the-art mapping technology. Check back often to view the DNR's progress and view new LiDAR maps
What is LiDAR?
LiDAR, which stands for Light Detection and Ranging, is a new technology that creates an interactive topographic map with elevation data accurate within eight inches. Current data has an accuracy of within five feet. LiDAR is a process of scanning the earth with lasers from an aircraft to obtain accurate elevations.
LiDAR is similar to sonar in that it measures distance by the time it takes for the laser to reach the ground and bounce back to the aircraft.
As a supplement to field surveys, LiDAR can be used to plan for road construction, other construction sites and conservation farming practices. It can also be used to evaluate alternative infrastructure options, for education and research purposes, and in engineering.
What will LiDAR cover?
The DNR plans to obtain LiDAR coverage and accompanying aerial photography for the entire state of Iowa.
These maps, as well as elevation maps for all Iowa counties, will be available for free on www.iowadnr.gov.
How accurate is LiDAR?
- Proposed project will generate elevation data which is within eight inches of actual elevations (currently available statewide data has an accuracy of ± 5 feet).
- Data will support development of 2-foot contours that meet national map accuracy standards and Federal Emergency Management Agency (FEMA) requirements.
- Data points used to generate elevation data will be spaced an average of 5 feet apart or less.
When would the data be collected?
- Depending on weather, the DNR proposes to cover one-third of the state over three seasons (fall 2006, spring 2007, fall 2007).
- During these times, there is no tree canopy to obscure the mapping mission.
- Desired start date is fall 2006.
How will the data be made available?
- The data is available in various formats at:
What are the total costs associated with the LiDAR project? (estimated $5.86 million)
- One year ago, the best prices were around 50 cents per acre.
- U.S. Geological Survey (USGS) recently negotiated a sole source contract with a vendor that states are eligible to contract with for the LiDAR project.
- Under this contract Iowa could be flown for 8.5 cents per acre.
- 36,000,000 acres in Iowa x $0.50 = $18 million
- 36,000,000 acres in Iowa x $0.085 = $3.1 million
- The DNR still needs funding for these LiDAR components:
- High-resolution photography (necessary complement to LiDAR for completing data processing and development of detailed elevation maps) ~ $1.5 million.
- Infrastructure necessary to store and distribute data over website ~ $200,000.
- Data handling, acceptance, quality control, distribution, etc. ~ $520,000.
- Project administration/coordination ~ $140,000.
- Delineation of floodplains ~ $400,000.
- Funds would be allocated as data are delivered to the state.
What are some uses of LiDAR data?
LiDAR will allow planners to greatly reduce and supplement field survey requirements for many Iowa businesses and agencies.
- Reduction of many infrastructure planning costs
- Roadway siting, planning, and estimating
- Utility line siting, planning, and estimating
- Construction site planning and estimating
- Soil conservation structure (terraces, sediment ponds, etc.) planning and estimating
- Risk assessment
- Floodplain and flood insurance mapping
- Erosion potential measurements and modeling
- Emergency management and response planning
- Dam breach inundation areas
- Levee analysis
- Spill routing
- Evaluating alternative infrastructure options
- Utility lines
- Stormwater facilities
- Permit process improvement
- Animal feeding operation siting with regards to floodplains and slope
- Air emission permitting
- Floodplain permitting for industrial/residential construction
- Environmental science
- Watershed modeling
- Runoff modeling
- Conservation practice performance
- Watershed delineation
- Construction site planning
- Development/use of automated planning tools
- Development of new technologies – potential for yet unimagined applications
Who is going to do the work?
- USGS will contract to obtain LiDAR and photographic data.
- IDNR will coordinate the data collection project with USGS.
- IDNR will assume the responsibility of processing and serving the data via the Internet to Iowans.