Geospatial nets long-term efficiencies

By Louis Demargne, Fugro EarthData, Inc.

The U.S. Conference of Mayors recently identified funding as the single biggest challenge to meeting infrastructure needs. Louis Demargne, Vice President of Marketing for Fugro EarthData, discusses how geospatial services can help fill these gaps.

As the American Recovery and Reinvestment Act of 2009 nears its first anniversary, many local governments – especially those in metropolitan areas – are yet to feel the impact. The forthcoming jobs bill may provide additional relief through infrastructure investments and small business capital. But in the meantime, cash-strapped county and municipal managers are looking for long-term efficiencies to stretch limited budgets. Geospatial technologies are providing some pretty compelling answers to that end.

Land-Use/Land-Cover: Making Best Use of Existing Data

Land-use/land-cover mapping supports a wide range of applications important to infrastructure planning and maintenance. Zoning, route planning, and storm water runoff are but a few of the potential data uses. Yet despite the obvious value these data provide, land-use/land-cover mapping is often seen as an "extra", something nice to have, but beyond the scope of available budgets. That's because base mapping needs tend to overshadow value-added datasets.

Comprising orthoimagery, planimetric, and topographic layers, base mapping is most often produced using a mix of natural color imagery and lidar mapping. Land-use/land-cover data, on the other hand, ideally requires data in color-infrared. Using conventional methodologies, this would necessitate a second aerial flight in addition to the base mapping mission, thereby increasing costs considerably. What's more, the process for developing land-use/land-cover mapping in the past has typically involved time consuming manual interpretation methods.

But that was then and this is now. Today's all-digital mapping environment has significantly streamlined land-use/land-cover mapping processes. To begin with, digital imaging sensors have gradually replaced conventional film cameras as the system of choice for photogrammetric mapping projects. These systems typically collect imagery in four spectral bands simultaneously: red, green, blue, and near-infrared. No second aerial mission is needed to collect the optimal dataset for land-use/land-cover mapping. And map production is further improved with use of a new, automated methodology that combines feature extraction software with classification and regression tree (CART) analysis. The result is faster, more accurate and more affordable land-use/land-cover data production.

This process was recently used in Horry County, South Carolina. Home to Myrtle Beach, Horry County is one of the nation's fastest growing areas. As such, it faces significant development issues, with increased storm water runoff chief among them. To evaluate the risk of flooding among the county's farmlands, residential areas, and world-class golf courses, the county performs GIS-based storm water modeling. The process relies on three critical datasets: terrain elevation, soil types, and land-use/land-cover. While the county had up-to-date, high accuracy elevation and soil data on hand, the ability to acquire updated land-use/land-cover proved a challenge. Having been selected to perform countywide base mapping in 2008, Fugro EarthData suggested using the existing multispectral imagery to benefit the county's storm water management needs, as well.

Land-use/land-cover mapping was completed in 2009 to great success. With the ability to accurately assess storm water runoff, the county is better able to balance continued development with infrastructure needs for managing storm water. Additionally, the data shows promise for safeguarding water quality by predicting pollutants that are being washed off particular types of land, as well as for estimating debris cleanup in the event of a large storm or hurricane.

Panoramic Mapping: Making Specialty Data Affordable

Another geospatial technology with the ability to turn the "extra" into the "essential" is panoramic mapping. This brand new capability, which Fugro EarthData debuted last summer, enables simultaneous acquisition of high resolution vertical and oblique orthoimagery from a single airborne mission. The benefits of oblique mapping have been well documented over the past five years, providing infrastructure managers and developers with information that supports urban planning, public works, asset management, property appraisal, and emergency response.

However, like the land-use/land-cover example before, maintaining base mapping layers often takes precedence over oblique mapping. As a result, jurisdictions may see several different departments contracting for separate airborne imagery acquisitions to satisfy individual end-user needs. The panoramic mapping system is helping to address these contracting inefficiencies through a number of different ways.

First is the ability to acquire vertical and oblique imagery simultaneously and at high resolutions, making multiple airborne missions a thing of the past. And because the system is designed to collect large swaths of data at high altitudes, far fewer flight lines are needed compared to traditional vertical and oblique mapping cameras. This makes data acquisition faster and more cost effective.

Second, the system is highly flexible. Mapping every angle of a given landscape, image output can be customized to user needs, rather than the other way around. If vertical orthoimagery is needed over an entire city, but oblique mapping over just the most densely populated areas, so be it. If a particular city block or even an individual building requires data from a specialized viewing angle, that too is possible. It's just a matter of outputting data to meet customer specifications.

And third, the system makes it easy to visualize and exploit the final mapping data in a three-dimensional environment. Panoramic data is delivered to customers along with an ArcGIS-compatible viewing and mapping software. This highly functional software allows users to pan and zoom, measure features, and search for infrastructure by address, geographic coordinate, or even parcel ID. Buildings can also be digitized and exported as textured 3D models. Available in a web server format, the unlicensed data and viewer allow an unlimited number of authorized users to simultaneously access and manipulate the data to meet their specific needs. All updates need only be made on a single server database.

The Tip of the Iceberg

Land-use/land-cover data and panoramic mapping are just two of the ways that geospatial is being used to stretch limited budgets. By maximizing the value of existing geospatial datasets and employing innovative technologies to develop data that supports an expanded range of infrastructure applications, local government managers are meeting that ubiquitous goal of "doing more with less".