Mapping the Badlands — Surveying and GIS Just Got Easier

A 1.419Mb PDF of this article as it appeared in the magazine—complete with images—is available by clicking HERE

Surveying and mapping here in southwestern Oklahoma can be a challenge. It’s a rough-hewn landscape with rugged terrain features and plenty of wide-open spaces. Since the historic land rush that gave the Sooner State its name, Oklahomans have been hard at work taming their wilderness and trying to create accurate and useful maps and surveys of their state.

My beat is the city of Lawton. With a population of just under 100,000, it’s Oklahoma’s third-largest city, a 50-square-mile area not far from Wichita Falls, Texas. In addition to the land within Lawton’s city limits, there’s an equivalent area comprising two large lakes adjacent to the city, and the army’s massive Fort Sill is nearby.

I’m an Oklahoma State University Adjunct and worked for many years as president of a survey and engineering company in Oklahoma City. I retired from that post, and I’ve been working in Lawton’s Engineering Division for nine years doing boundary work and surveying for all the departments, GIS data gathering for Public Works, Infrastructure and other departments, and geographic management of all survey and engineering data in Lawton. In fact, Lawton’s GIS was born the day I started work here. Before that, Lawton, like many small to medium-size cities, relied on "junk" information — poor-quality maps and inadequate spatial information. Our data was non-digital and sketchy. My task: to move us into the digital age.

Our Secret Weapon
One of our secret weapons of late has been MobileMapper Pro, an easy-to-use handheld GPS survey system from Thales Navigation that saves time and manpower on a variety of city survey jobs. In many ways, it’s a real jewel.

We bought Mobile Mapper about 18 months ago. We learned the system quickly and now we toss it in the truck each morning and use it to gather a variety of data every day. It’s a real time saver; we’ve paid for it 10 times over.

The MobileMapper has completely replaced total station systems for GIS work and many other applications. It costs a small fraction of a total station and unlike the older product we used, software upgrades are free.

It’s a valuable tool, whether we’re using it for reconnaissance, as a navigation tool or for surveys that require post-processed accuracy. We’ve stored .shp files of all City of Lawton controls, water and sewer lines, streets and much more in MobileMapper Pro. We can use it to navigate to a known location, and review the attributes and make changes if need be.

Surveying Without Setup
For survey work with the MobileMapper Pro I don’t have to worry about taking the time to set up it up as I did with the older equipment. We just take out the MobileMapper Pro, get it to postprocess and move on. Lawton has a local CORS operating around the clock. With that base station, we know from tests that when we postprocess the data, MobileMapper Pro delivers sub-foot accuracy 99 percent of the time–and that’s vertical feet. It’s just outstanding.

In the course of a day we may use the MobileMapper Pro to quickly gather data on as many as four or five projects. That might mean logging latitude and longitude of items of interest, such as a new cell tower to be entered in the GIS; or it might mean finding out whose land the tower is on. We might need to map a trash pile somebody has dumped or to take on various jobs requiring sub-meter post processing.

If, for example, Public Works wants to begin replacing older fire hydrants, we’ve got the efficient way of doing that. Instead of waiting for the existing hydrants to break, we can go into MobileMapper Pro and quickly identify hydrants of a certain type that were manufactured prior to 1940. Instead of two trips–one to inspect and identify the equipment and one replace it–crews can go straight to the sites knowing which ones are slated for replacement.

One recent project involved mapping the location of rocks that had been taken from a demolished waste-water treatment plant. The rocks had been used around the city for several purposes, including street patches and riprap for creeks. When it was found that mercury might have leaked into some of the rocks, their locations needed to be mapped for cleanup planning. In one afternoon, we mapped 30 spots spread over a 40-squaremile area. Without the MobileMapper Pro we would have used total stations or made chain ties from corners. It would have taken us a week or more.

Mapping a Heliport
MobileMapper Pro was at its most productive recently when we were called on by the city Planning Department to check out a new heliport at a local hospital. The hospital’s old pad was a long way from the emergency room, and they wanted the new one closer in. They had purchased several houses nearby and cleared them out to create the pad and an adjacent parking lot. Our job was to map the whole area with an eye to checking compliance with noise level codes and other regulations.

We had an established control point across the street from the hospital, which simplified the matter considerably, but even so it was remarkable that the MobileMapper Pro enabled us to gather the line work and shoot points on the existing pad and fence in less than five minutes. A drawing of the shot we took before processing the data appears here. The MobileMapper Pro was operating autonomously using WAAS at that point. Later we exported the shot and did a quick site plan to show the dimensions in the context of nearby houses and streets.

The whole project took us about 20 minutes, a small fraction of the time it would have taken with total stations. No boundaries were required and we only needed to estimate distances in this case. It wasn’t technically a GIS file, and it didn’t become part of our base map, but it was a very useful map for city council presentations and other informal purposes.

We put MobileMapper Pro to work on a somewhat different application recently when we were asked to map water lines running through the army’s vast Fort Sill. We walked some eight miles through some unusually rugged terrain and completed the job with no hitches. It turned out, though, that we’d been working in some areas that were down-range on firing fields in which live artillery rounds were said to reside: not what we expect on our typical survey assignments.

Mostly, though, MobileMapper Pro is handling many of the relatively mundane chores that public works and planning departments face on a daily basis. We’re building a base map that’s making everyone more productive: firefighters, utility crews and everyone else that works to keep Lawton running smoothly. And thanks to MobileMapper Pro, we’re doing all this in ways that are fast, efficient and easy on the city treasury.

Deral Paulk was the subject of our ProFile story in the March/April 2004 issue. He manages the surveying and GIS department for the City of Lawton, Oklahoma.

A 1.419Mb PDF of this article as it appeared in the magazine—complete with images—is available by clicking HERE