Easement-holding organizations can utilize a variety of technology tools to track their easement stewardship activities. Microsoft Access or Filemaker Pro are two databases that can track information such as property owner contact information, approvals, inspections, property data, and more. However, geospatial technology can provide organizations with additional tools that can aid in the ongoing stewardship of preservation and conservation easements. At the National Trust for Historic Preservation, we developed a geospatial boundary dataset and a GIS application to improve the stewardship of our over 135 easements in 26 states and the District of Columbia. This project was a collaboration between the National Trust’s Easement Program and GIS staff, with each team member bringing specific technical knowledge to streamline the process.

Creating the Dataset

The National Trust Easement Program’s files are entirely digital and organized on a shared Easement Drive, which helped facilitate multiple staff members collaborating on this project. The Easement Program utilizes an Access database to track significant property level data, including the address, Google Maps location link, property owner name and contact information, recent inspection information, an index of approvals, and more. To begin the project, we extracted specific data from the Access database into a collaborative Excel document. In this Excel spreadsheet, we tracked:

• Property Name
• Secondary Property Name (if any)
• Link to the property’s folder on our internal Easement Drive
• Address, City, State, ZIP
• Link to location on Google Maps
• Acreage
• Link to a survey or reference map on our internal Easement Drive
• County/State website with publicly accessible GIS parcel data
• Additional comments/guidance

As preservation and conservation easements generally include the entire parcel of the protected property, it was critical to ensure the property boundaries were accurately identified and drawn. Easement Program staff researched and provided two important pieces of information to streamline the creation of geospatial data for each easement property.

1. Reviewing each property’s file and identifying a boundary survey (or other map) that accurately detailed the property’s legal boundary protected by the conservation easement. In some situations, a boundary survey was not available, and a property’s legal description was utilized;
2. Researching and identifying a link to publicly available parcel data. Most properties had parcel data available either through the county GIS department or from a state agency.

As can be imagined, some easement properties were incredibly easy to create spatial data for, while others required more advanced research and techniques such as georeferencing to achieve the creation of accurate and useful digital boundary data.

Building the Application

Once boundary data had been completed for each easement property, National Trust staff worked together to determine the best way in which the new data could be made easily accessible and useful during day-to-day operations. A decision was made to use one of Esri’s ArcGIS Online configurable, no-code-required mapping applications. These applications can be easily created and maintained, while providing a number and variety of analtyic tools. After the decision to use a configurable application was reached, an easement application was created and deployed within just a few days. The new application achieved a mix of stripped-down simplicity with a small number of useful tools that Easement Program staff can use for common tasks and analysis including measurement, basemap change, and search tools.

Collectively, organizing the property level data, creating the spatial data, and building the application took around 100 staff hours.

Application in Practice

With the application completed, we’re exploring a variety of new ways to use the GIS application and associated easement boundary data. For example, the measurement tool included in the application provides a useful method for conducting reviews of proposed changes or activities at National Trust easement properties. Utilizing the tool, we can better understand the size, scale, and relationship of proposed activities. Additionally, layering the aerial imagery basemap below the property boundaries provides us more information about the uses, landscape, and other natural features protected in our easements.

Land trusts are utilizing remote monitoring as an additional stewardship tool, particularly during the pandemic. The National Trust is exploring aerial monitoring for certain conservation easements, particularly those that are difficult to visit or large parcels that can be challenging to fully inspect on the ground. We uploaded the completed shapefiles to a company that provides recent high resolution satellite imagery. Remote monitoring cannot replace in-person site visits for protected historic properties, but it can improve the monitoring process for larger conservation parcels while providing an alternative for a handful of properties that are difficult to monitor on the ground.