This map is an independently developed public-advocacy tool for understanding the PSEG Maryland Piedmont Reliability Project, a proposed 500 kV transmission line cutting through Frederick, Carroll, and Baltimore counties. It is built to help residents see where the line is being proposed, who it affects, and what it would look like from the ground.
This map is not a PSEG product. It is built and maintained by Will Sykora, an affected landowner and pro se intervener in Maryland Public Service Commission Case 9773. The goal is to give other affected property owners an honest, citable view of the project, drawn from the same public datasets that regulators and PSEG's own consultants rely on.
The current route is PSEG's June 2026 adjusted proposed route, which includes their micrositing changes. The September 2025 route and the original December 2024 CPCN submission are available for comparison. All three come directly from PSEG's public ArcGIS feeds, as do the 313 proposed tower locations, access roads, and tower pads.
The ground-level and first-floor visibility analyses (viewsheds and impact corridors) have been recomputed for PSEG's June 2026 tower positions. The second-floor view is still from the September 2025 positions and is being recomputed; most towers did not move, but about 28 moved by up to roughly 1,070 ft, so it is approximate near them.
Conservation easements, agricultural preservation districts, historic properties, National Register sites, and the Linganore American Viticultural Area boundary are layered on top, pulled from Maryland iMAP and the UC Davis AVA repository. Existing transmission lines and substations come from the federal HIFLD dataset.
Tree canopy and terrain are rendered from December 2024 LiDAR flown by USGS, the most recent high-resolution survey of the corridor. Roughly 46,000 individual tree cells are shown at their measured heights. Trees inside the right-of-way are removed from the view to simulate the post-construction clear-cut.
What you would see, hear, and be exposed to. Viewshed polygons show where each tower would be visible from, banded by distance. A 250-foot audio buffer approximates the audible corona noise from a 500 kV line in rain, based on EPRI's standard reference. Three nested EMF bands approximate magnetic-field reach under typical loading.
The Affected Parcels layer lists every Maryland property
whose recorded boundary is crossed by PSEG's June 2026
right-of-way. Parcel boundaries, addresses, and deeded
acreage come from the State Department of Assessments and
Taxation (SDAT) parcel layer published on Maryland iMAP
(MD_ParcelBoundaries). The acres inside the
right-of-way were computed by intersecting each boundary
with PSEG's published ROW polygon in Maryland State Plane
coordinates; overlaps under about 0.01 acre are treated
as boundary-touching artifacts and left out, as are road
right-of-way records. Parcel boundaries in the state layer
are approximate and are not a survey. Owner names are never
fetched or shown. Clicking a parcel outside the set looks
it up live from the same state layer.
The terrain and canopy models are derived locally from USGS
3DEP LiDAR (project MD_4County_D24, December
2024 leaf-off acquisition) using PDAL, an open-source
point-cloud processing library. Deriving the digital
elevation model directly from the source point cloud,
rather than using USGS's published tiles, gives complete
coverage across the 70-mile corridor and keeps the terrain
and canopy datasets internally consistent. The result is a
1-meter (~3.3 ft) resolution model built from the newest
available data, which is methodologically equivalent to or
stricter than the 3-meter (~10 ft), 2014 to 2021 LiDAR
that PSEG's own consultants at EDR used in their visual
impact analysis.
Viewsheds are computed by ray-marching line-of-sight from each tower at 5-meter (~16 ft) steps across an 8-meter (~26 ft) grid, with output banded into five distance rings from 0.5 to 5 miles. Tower-to-tower wire connections are reconstructed by geometric nearest-neighbor chaining because PSEG's published object IDs are not route-sequential.
Base imagery comes from Esri, CARTO, USGS, OpenStreetMap, and OpenTopoMap.
The LiDAR is from December 2024 and the landscape may have changed since. Viewsheds assume a stationary observer and treat tree canopy as opaque, so real-world visibility varies with weather, season, and time of day. The audio and EMF buffers are approximations from published reference data, not site-specific measurements. This is a public-advocacy and case-preparation tool, not engineering- grade design data, and it does not substitute for professional appraisal, environmental, or legal analysis.
This tool supports public participation in Maryland Public Service Commission Case 9773. Maryland Public Utility Companies Act Section 7-207 governs Certificate of Public Convenience and Necessity review for transmission line construction in Maryland. Affected landowners have the right to intervene, submit comments, and testify.