Georeferencing

 For this week’s blog I decided to georeferenced a map from downtown Columbia in 1898 which depicts buildings between Sumter, Marion, and Bull Street. After georeferencing the map I added polygons to depict the main buildings in four street blocks (Map 1). I created an attribute table to add the house number, street name, number of floors, and the type of building (Fig. 1). After completing the table I used the “Unique Values” in Symbology and used BuildingType as the field to color the polygons. This allowed me to change all the domicile buildings to dark green, churches to white, and unknown / commercial to purple. There were three unknown buildings that had names associated with them, however the map keys did not provide me with the specific type of building, so I chose to label them partially as 'unknown" as to not assign my own interpretation onto the buildings. In the attribute table notes I added the building’s name, so it’s recorded along with the building type.

Map 1

    Figure 1

After completing this map, I checked through Sanborn maps for 10 years earlier to see if the buildings had changed. It was difficult to find a map that matched the one I had already georeferenced but after finding two, when combined, showed the same area as my 1898 map, I realized there wasn’t a large change. That's why I decided to compare the 1898 map to a 2025 map.

I used a combination of the ArcGIS Pro basemap and GoogleMaps to determine the building locations and types for my 2025 map. I then added polygons to represent those buildings, and color coded them for the types. This comparison showed me that there was a massive shift in building types (which is to be expected after 100+ years) however, the shift moved from all but 5 buildings being domiciles to only 2 by 2025 (Map 2). 

Questions we can investigate using these maps and the information contained on these maps are:

When did the shift occur from majority domicile to majority commercial?

Why did people relocate? And where did they relocate?

What events may have occurred that caused this change?

Was this part of a larger city plan?

Was economic growth a factor?

Did any weather or fire events impact this shift?

What are other layers you could combine information found on the Sanborn maps (both geographic or attributes) to investigate a topic, questions, or historical argument?

The maps show where fire hydrants and fire houses were located. In the event that fire may have played a part in the commercialization of part of downtown Columbia, knowing where fire hydrants were and how quickly firefighters could respond and get the fire under control could help.

Additionally, many of the maps show the type of materials used for the buildings such as frame, brick, stone, iron, etc. This will assist in determining if events such as a fire or weather event may have impacted that specific building.

Another way to determine when a shift occurred would be to review the maps from different years, allowing us to see when there is a shift in building changes.

 

Historical Rewrite:

For this week’s blog, I georeferenced an 1898 map of downtown Columbia showing buildings between Sumter, Marion, and Bull Street. I added polygons for buildings across four blocks and created an attribute table with house number, street name, number of floors, and building type. Using unique value symbology, I color-coded domiciles (dark green), churches (white), and commercial/unknown (purple). For three named but unidentified buildings, I marked them as “Unknown” in building type but recorded their names in the notes section.

I compared this 1898 map with a Sanborn map from 1888 and with a 2025 map. The Sanborn maps showed little change, but the 2025 comparison revealed a major shift from almost all domiciles in 1898 to only two by 2025. This raises questions:

1)       When and why did the shift from residential to commercial occur?

2)       Where did residents relocate?

3)       Did city planning, economic growth, weather, or fire events help drive this change?

Sanborn maps can offer additional layers for investigation. Fire hydrants and firehouse locations, along with building materials (frame, brick, stone, iron), could reveal how fire or weather shaped redevelopment. Additionally, comparing maps from multiple years would also help pinpoint when major shifts took place, making it easier to research what events preceded the change.