Denison City Hall

A partnering of several entities will lead to better features for the next generation of geographic information system (GIS) maps of Crawford County.

Last Tuesday, Crawford County Assessor Duane Zenk explained to the Denison City Council that the firm that had been doing the GIS mapping, Sidwell, is no longer providing that service.

Sidwell representatives referred him to EagleView, and Zenk found that firm offers a number of products that would enhance the usefulness of aerial maps – oblique (three-dimensional) views in addition to the base (one-dimensional) aerial photography, views from four directions (north, east, south and west) and Light Detection and Ranging (LiDAR).

City Manager/City Engineer Terry Crawford explained the LiDAR allows users to put elevational contours on a map of a piece of ground.

He said that he currently has Sundquist add this to maps.

“Most of the areas we were considering for annexation, I did LiDAR contours on so we could look at layouts of commercial lots,” Crawford continued. “It helps tremendously from an engineering standpoint to be able to tell how the ground lies so you can serve it with a gravity flow sanitary sewer and see how different things would lay out.”

Zenk said being able to see all four sides of structures will add a big dimension to a lot of the uses of the GIS maps.

“They would be a lot better for all of the uses, not only for assessment but zoning purposes. You could see how many stories a building is and the setbacks from streets,” Zenk explained.

Crawford and City Clerk Lisa Koch said that the GIS maps are used multiple times every day at the city hall.

Police Chief Dan Schaffer added that his department uses the GIS system all the time, “not only in building and code enforcement but we use it for investigative purposes. We’ve used it in emergency situations as well. When we’ve got to find something we can’t find anywhere else, that’s our best tool to go to. With the three dimensional views, that would make a huge difference in some of the investigative things we use it for as well.”

Zenk said EagleView serves probably three-fourths of the counties in Iowa.

He continued that 100 LiDAR subscriptions some with a contract with EagleView. He said that would give plenty of room for people to use LiDAR with the maps at the same time.

“I don’t think we’d have 100 users at any one time that wanted the LiDAR or the more in-depth part of it,” he added.

The most recent aerial photography of Crawford County was flown in 2017. Zenk said typically new mapping is done about every three years.

Annual payments would be $36,862.17.

Zenk said EagleView offers a three-year contract with another three-year renewable option that guarantees the price for those additional three years.

Zenk said the initial cost for the base mapping is a little over $18,000. “To go to the next three dimensions and LiDAR and the other things we’ve talked about is about $18,000 more for that,” he added.

Zenk continued that he has the $18,000 already committed from partners for the basic aerial service and he asked if the city would be willing to participate at $10,000 a year. He said he has a couple other parties that he wants to work with on funding.

The contract with EagleView would begin with the next fiscal year, on July 1.

Zenk hopes the flight for the mapping would be done on November 1 this year, pending no snow cover.

The maps would be delivered 90 days later.

He explained that they want to do the mapping when the leaves are off the trees in the fall or before the buds appear on trees in the spring.

“I’ve had years when we had to wait until spring,” Zenk said. “We don’t want snow.”

The city council agreed to a three-year commitment and made a motion to put up to $10,000 in the budget.

Koch said the funding for the city’s share would most likely be taken from Local Option Sales Tax.

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