Aerial Maps Delayed By Imaging Troubles
Mississippi Hinds County's plans to update aerial property ownership maps to comply with a state Tax Commission mandate have run into a snag. May not mean a lot to most people but if you're searching for a conventional or digital map of Iowa or need aerial photography of Georgia, you need to take note.
"It's a small stumbling block now, but we want to make sure it doesn't become a large stumbling block," Tax Assessor said.
The stumbling block is that digital copies of aerial maps produced so far don't show areas outside the city limits. The areas appear either black or white. Which is unacceptable.
At stake for Hinds County is $8 million a year in homestead property tax reimbursement and $1.3 million set aside annually for property reappraisal. The state will withhold the funds if aerial maps aren't updated by Oct. 15.
Hinds County wants Neel-Schaffer Inc., which is preparing the computerized maps, to correct the problem at no additional cost.
The tax accessor said it should cost about $1,000 to correct the map problem.
"I don't know if we will do it at no cost," said senior GIS specialist for Neel-Schaffer. "We did it exactly the way the contract said."
He said Neel-Schaffer created two images, one for the city and one for rural areas. "They want a single image," he said.
He said both images can be viewed simultaneously, but it requires Hinds County to merge the two maps.
Hinds County supervisors agreed to spend more than $100,000 to upgrade the maps.
The county is converting aerial maps to digital technology so they can be called up by computer. Digital photographs shot in 2007 and 2008 are being used.
After looking over a high-tech aerial topography map, town officials think they might have to do the measurements over again -- this time the old-fashioned way by walking the property.
A map used to plan a new, $9 million elementary school is inaccurate and must be redone, to the tune of $6,000 extra and another month's work, the project engineer told building committee members.
Readings made at several points around the 30-plus acre site during soil tests by engineer showed that elevation measurements were anywhere from 6 inches to 3 feet lower. The town council in 2008 approved the $400,000 purchase of the maps from Aerial Data Reduction Associates, with the intent of mapping the entire town in 250-acre sections.
Because the elevations -- the height of the land above sea level -- are determined by computerized comparison of photographs taken from an airplane, there is a margin of error in all of the maps' accuracy, town Development Director said. If the photos of the acreage off Rhodes Road were taken where evergreen shrubbery was thick, blocking the camera's sightline to the ground, the computer could have read the height of the shrubbery as the elevation, he said.
Other aerial maps used for previous projects have been "within inches" of accuracy which bodes well for other states interested in state of the art aerial maps indiana or any others.
If approved by the school board, the plans will then go to the state Department of Education. The new survey is only part of the package and can be submitted later, but still before the state begins its review, project architect said.