It's one thing to point out in a news story that 12,000 houses in the Columbus area were listed for sheriff's auction during the past five years. It's quite another to publish an eye-popping map that instantly shows the toll of foreclosures in communities across Franklin County - far beyond the inner city and poor neighborhoods.

Projects reporters Jill Riepenhoff, Geoff Dutton and I called it our "holy crap map."

No one - lenders, Franklin County government officials or homeowners - could diminish the scope of the problem. The map provided the foundation for "Brokered Dreams," a four-day series about foreclosures and mortgage fraud published Sept. 18-21, 2005. (The series is posted online at www.dispatch.com/reports/reports.php) A little less than two months later, the Chicago Tribune reported how widespread mortgage fraud was hurting poor communities in the city.

We used ESRI ArcView geographic information system (GIS) software repeatedly during the reporting, writing and editing of the series. Mapping software would strengthen just about any story involving property parcels.

By far, the countywide map of properties sent to sheriff's sales from 2000-04 posed the biggest challenge. The time gathering and cleaning data paid off because the map guided much of the reporting that followed.

The sheriff's department provided a text file with properties sent to auction. That data set included the parcel identification number, which proved invaluable in linking the information to the more-detailed auditor data. Joining the data on the street address field would have been a data nightmare of epic proportions, given the inconsistencies, typos and other data-entry problems.

Once we produced a master table of properties sent to sheriff's sale, we spent hours cleaning it up and standardizing information gathered by two separate county offices. The auditor's data included fields that helped us produce a master table that included only single-family properties. We excluded commercial buildings, apartments and other properties that went on the sheriff's auction block to keep our focus on single-family homes.

When we were confident that our data showed what we wanted, we joined the table using the parcel ID field to the auditor's layer file. Presto: our "holy crap map."

The map breathed life and meaning into our table of nearly 12,000 single-family homes sent to sheriff's sale. We expected to see dense concentrations of sheriff's sales in poor, central-city neighborhoods but never dreamed there would be so many foreclosures outside Interstate 270, the outer belt ringing Columbus.

A printout of the map left Franklin County Treasurer Richard Cordray nearly speechless. "Wow," he said. "Wow."

For a time, we considered using the map as the lead art on Page 1 with the kick-off story. Ultimately, we chose a photo showing workers removing furniture from a foreclosed house, a visceral image that best represented loss of a home. The map also would have eaten up too much space on the cover. The fact that we even considered a large map as lead art shows how far our newsroom has come in its use of digital mapping.

With our countywide ArcView map, we were able to take a closer look at subdivisions all around the outer belt. Many of those neighborhoods have fairly new houses - homes built within the past five or 10 years. We created a theme map showing foreclosed properties based on the home builder. In some subdivisions, several builders had put up houses. In others, a single developer had built the homes. ArcView enabled us to see quickly whether clusters of foreclosures involved a single builder.

Mapping played a pivotal role in driving home the key findings in the series. Other key maps produced for "Brokered Dreams" included:

A detailed look at one Columbus subdivision, Galloway Ridge, which had been riddled with sheriff's sales and personal bankruptcies. The map vividly showed the devastating toll on a neighborhood where nearly one in six households had faced foreclosure, bankruptcy or both. We produced the map by combining sheriff's sale and bankruptcy data and then linking it to a parcel layer. Riepenhoff took a printout of the map with her as she knocked on doors and talked with Galloway Ridge residents about their deteriorating neighborhood. Many knew that foreclosures and bankruptcies were harming their eight-year-old subdivision, but few realized the scope of the problem until they saw the map.

An overview showing how 390 houses financed by a New York City hedge fund were clustered in poor Columbus neighborhoods. Those ramshackle houses had been flipped (sold quickly at huge markups) and left vacant, adding more eyesores to struggling areas. A tipster alerted Dutton to irregularities involving houses financed by the Stillwater Asset Backed Fund.