Question 1

Can GPR Determine the Exact Size of a Subsurface Void Cavity?

Accepted Answer

Ground-Penetrating Radar can reliably reveal the presence and general boundaries of a buried void, but its reflections blur at depth. GPR therefore estimates a cavity’s width and depth within a tolerance—often a few inches—rather than providing an architect-grade “exact” measurement for most cemetery-mapping projects today.

Ground-Penetrating Radar (GPR) sends high-frequency radio waves into the ground and records the echoes. A void—whether an underground chamber, abandoned utility vault, or the airspace above a collapsed burial—creates a strong, hyperbolic reflection that stands out on the radargram. By collecting parallel survey lines and processing them into 3-D slices, technicians can outline the lateral footprint and estimate the roof and floor of the cavity. Within a cemetery mapping project, this ground penetrating radar cemetery survey is correlated with precise GPS for burial plot mapping.

Signal wavelength, soil conductivity, moisture, and void depth all smear the reflection, so the interpreted edges usually carry a ±2 to 6-inch margin of error. Very shallow, dry, sandy soils yield the sharpest images; deep clay soils can stretch the error band to a foot or more. In practice, GPR delivers a dependable “box” around the anomaly.

For cemetery managers, Sentry Mapping uses ultra-high-frequency antennas to capture the clearest possible view of underground disturbances. The same workflow that distinguishes intact graves from empty plots also flags subsurface hazards, helping you avoid collapses during maintenance or future burials. Learn more in our Complete Guide to Ground Penetrating Radar.

Question 2

How can a churchyard with limited resources modernize its cemetery record-keeping?

Accepted Answer

Even on a tight budget, a churchyard can convert paper documents to digital records by outsourcing one turnkey survey. Sentry Mapping uses ground-penetrating radar, precision GPS and free web-map delivery to capture every marked or unmarked burial, then loads the data into Chronicle cemetery management software so volunteers can update records online.

Start with a professional cemetery mapping survey that respects tight budgets. Sentry Mapping offers a free estimate and can usually complete a small churchyard in less than a week. High-frequency ground penetrating radar cemetery equipment sweeps the entire site without digging, locating every headstone, footstone and hidden burial. Precision GPS fixes each plot, and our team reconciles old notebooks, ledgers and memory with the new data to prevent duplicate sales or accidental disturbances.

Within weeks you receive a printed master map plus an interactive cemetery GIS mapping portal that anyone can open on a phone, tablet, or computer. Volunteers simply type a name to see a grave’s exact coordinates, photos and available space nearby. Because the map lives in the cloud, the church avoids servers, licenses or IT headaches. Two complimentary years of Chronicle cemetery management software let you keep adding deeds, obituaries and maintenance notes.

The result is sustainable digitizing of cemetery records at a fraction of the cost of hiring surveyors or buying standalone cemetery mapping software. Accurate burial plot mapping today safeguards heritage, streamlines grave locating for families tomorrow and gives congregational leaders confidence that every future interment is in the right place.

Question 3

Is Ground Penetrating Radar Safe to Use?

Accepted Answer

Yes. Ground Penetrating Radar (GPR) is considered safe for operators, cemetery staff, and visitors. The equipment uses very low-power radio waves—about one-thousandth the strength of a cell phone—so it does not disturb human remains, monuments, or nearby electronics. Surveys are noninvasive, silent, and require no digging.

Ground Penetrating Radar transmits non-ionizing radio pulses (typically 250–900 MHz) through the soil and measures the echoes. The power output is less than two watts—roughly the same as a household Wi-Fi router—so it poses no radiation or electrical hazard to people, animals, pacemakers, or headstones. Because the signal loses strength within a few feet of the antenna, nothing outside the immediate scan line is affected.

During a Sentry Mapping cemetery survey, certified technicians push a lightweight GPR cart across the turf. There is no drilling, excavation, or contact with caskets, meaning remains stay undisturbed and the landscape shows no evidence of the work once the wheels roll past. All equipment meets FCC Part 15 emission limits, and our team follows OSHA and cemetery-industry best practices for PPE, site control, and respectful conduct.

The result is a completely non-destructive way to detect unmarked graves, confirm plot boundaries, and digitize records. Managers get precise GPS-tied data for every burial, plus an interactive cemetery GIS map and two years of free Chronicle cemetery management software—without risking visitor safety, staff health, or the integrity of historic sites. In short, GPR delivers the safest, most reliable path to modern, professional cemetery mapping.

Question 4

What is the average cost per acre for a cemetery mapping project using ground‑penetrating radar?

Accepted Answer

Sentry Mapping provides a free, no-obligation estimate for each project. Every property is unique and the exact cost varies with soil type, terrain, tree cover, and record condition. Quotes include full GPR coverage, high-precision GPS positioning, drone imagery, and the conversion of raw scans into a color-coded digital cemetery map with printed and interactive deliverables.

On a typical project, Sentry Mapping prices cemetery mapping on a per-acre basis, adjusting the rate only when unusual features demand extra field time. Smaller, wooded, or hilly sites sit near the upper end because thick roots, uneven ground, and heavy clay slow data collection. Flat, open acreage with sandy soil processes faster and often lands closer to the lower figure. Per-acre pricing also drops when you survey several adjoining acres at once, because crew travel and equipment set-up are spread over more ground.

The quoted rate covers far more than a quick sweep. Sentry Mapping’s team grids every square foot with high-frequency GPR and sub-inch GPS to detect marked and unmarked graves. Drone imaging captures a current orthomosaic. Our GIS specialists then turn raw scans into a color-coded digital cemetery map that pinpoints each burial plot, labels ownership, and links photos or documents. You receive a printed master map, an interactive web map with no annual subscription fees, and two years of complimentary access to Chronicle cemetery-management software so staff can update records in real time.

Because every property is unique, Sentry offers a free, no-obligation estimate. Most managers find the service pays for itself by preventing lost plots, avoiding costly digging errors, and opening up sellable space revealed during the survey. Click here to contact us today to discuss your site and receive a customized quote.

Question 5

What is the difference between a “burial-plot map”, a “web-map”, and a “GIS survey”?

Accepted Answer

A burial-plot map is the precise, static master layout of every grave and available space, produced from a one-time GPR/GPS survey. A web-map is the online, clickable version of that map that staff and families can access online to search from any device. A GIS survey is the underlying field data-collection process that feeds both products.

Think of the three deliverables as steps in one streamlined cemetery-mapping workflow.

1) During the GIS survey, Sentry Mapping technicians walk every row with survey-grade GPS and ground-penetrating radar equipment. The instruments record x-y coordinates, depth readings, and attributes—marked and unmarked grave locations, utilities, pathways, trees—creating a rich spatial database. This is the foundation of professional cemetery GIS mapping and integrates seamlessly with municipal or county GIS systems.

2) We produce the burial-plot map from the GIS survey data. This is the authoritative, to-scale master plan you can print, frame, or keep on the grounds. Every lot line, section number, and interment is plotted in its exact position, so you instantly see which plots are occupied, reserved, or available for sale.

3) We then publish the same data as an interactive web-map so your staff, grounds crew, and even visitors can zoom, search a name, or tap a grave for details on a phone or tablet. The web-map lives in the cloud, receives free updates when new burials are added, and links directly to Chronicle’s cemetery management software for digital record-keeping.

Together, the GIS survey, burial-plot map, and web-map turn outdated paper charts into a living, searchable, digital cemetery mapping system that eliminates double-sold plots, speeds grave locating, and preserves your cemetery’s heritage for generations.

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