They Go Where They Know: Forensic LiDAR Mapping for Investigative Search Areas
Updated: 3 days ago
When an investigation involves a wooded property, rural corridor, drainage system, abandoned parcel, or large area of difficult terrain, the question is rarely just, “Where should we search?”
A more useful question is: What locations were known, reachable, practical, concealable, and consistent with the available time and case facts?
That question may arise in a long-running cold case, but it can be equally important in an active missing-person investigation that remains unresolved after days, weeks, or months. It may arise when an initial search has been completed, when new information becomes available, when a private investigator is retained, or when a family and legal team need a more structured way to evaluate a large and difficult landscape.
LiDAR terrain analysis does not determine what happened to a missing person. It does not replace law enforcement, qualified search personnel, or field verification. It provides an additional decision-support layer: a way to examine terrain, access, travel effort, visibility, and physical constraints beneath vegetation and across large areas.
“They go where they know” is not a rule, and it is not a substitute for investigation. It is an investigative question. When a person must make decisions under stress, time pressure, fear of detection, or a need for control, familiar routes and locations may matter more than the most remote place visible on a map.
Aerial LiDAR can help turn those questions into a documented, terrain-based search strategy. Forensic LiDAR mapping provides a practical framework for reviewing terrain, access, visibility, travel effort, and search-area constraints in missing-person, homicide, and cold-case investigations.
Familiarity, Planning, and Opportunity
Not every case begins with the same level of planning.
Some events may be sudden, emotionally charged, or connected to an intimate-partner or close personal relationship. In those circumstances, a person may have limited time, limited equipment, limited ability to travel far, and a strong need to leave an area quickly. Their practical choices may be shaped by familiar roads, pull-offs, trails, rural property, hunting areas, work routes, drainage corridors, or places they believe are less likely to be observed.
Other cases may involve greater planning. But planning does not necessarily mean a distant or unfamiliar location. A person may instead choose a place already within their normal activity area: a property they know, a road they regularly travel, a work area, a recreational site, a place connected to family or associates, or terrain they have previously explored.
Research involving serial-murder disposal-site selection found that disposal locations often reflected familiar travel distances around an offender’s home base and were associated with the offender’s broader routine activities. The research also found that an offender’s spatial activity area could expand over time.
For investigators, the issue is not simply, “Where is the most remote location?”
It is: “What locations were familiar, reachable, practical, and perceived as low risk within the time and circumstances of this case?”
Forensic LiDAR Mapping Reveals the Terrain Beneath Vegetation
LiDAR can penetrate vegetation and create a Digital Terrain Model, or DTM, representing the bare-earth surface below trees, brush, and other ground cover.
That terrain model can become the foundation for multiple investigative map products.
LiDAR-derived product | What it shows | Potential investigative value |
Digital Terrain Model | Bare-earth elevation | Reveals terrain structure beneath vegetation |
Hillshade | Terrain illuminated from simulated light angles | Highlights subtle surface changes, grades, ditches, berms, old roads, and depressions |
Multi-directional Hillshade | Terrain shaded from multiple directions | Helps reduce feature concealment caused by a single light angle |
Elevation map | Relative height across the landscape | Helps identify ridges, low areas, benches, and terrain transitions |
Contours | Elevation intervals | Supports search planning, route assessment, and map communication |
Slope map | Ground steepness | Identifies areas requiring greater physical effort to cross or carry through |
Aspect map | Direction a slope faces | Helps interpret downhill travel, drainage direction, exposure, and terrain orientation |
Hydrology model | Flow direction and accumulation | Identifies gullies, drainages, low points, and terrain-defined corridors |
Viewshed analysis | What can be seen from a road, trail, residence, or observation point | Helps assess exposure, visibility, and potential concealment |
Cost-distance model | Travel effort across the landscape | Models practical movement based on terrain, slope, barriers, access, and distance |
Road and trail proximity map | Distance from access routes | Helps evaluate accessible areas, pull-offs, service roads, and likely entry points |
No individual map layer proves that an event occurred at a particular location. Their value comes from combining terrain information with known investigative facts.
Missing-Person Search Context
A missing-person case does not automatically imply foul play, and terrain mapping should never be presented as a conclusion about what occurred.
Instead, LiDAR and GIS analysis can organize known information into a practical, map-based assessment. This can be valuable when a missing-person case remains unresolved beyond the initial response period or when a private investigator, attorney, or family representative needs a structured way to review the physical environment.
Depending on the facts available, the assessment may include:
Last-known location and confirmed timeline
Known destinations, routines, travel routes, and personally significant locations
Vehicle information, likely access points, and possible pull-offs
Roads, trails, utility corridors, waterways, and terrain barriers
Slope, elevation, drainage, visibility, and vegetation conditions
Areas physically difficult or unlikely to reach within an available time window
Previously searched areas and locations requiring renewed or more focused field review
The National Missing and Unidentified Persons System, or NamUs, is a national repository and resource center supporting missing, unidentified, and unclaimed-person cases in the United States.
For a private investigator or legal team assisting with an unresolved missing-person case, LiDAR-based mapping can provide a documented framework for reviewing known locations, likely access routes, terrain constraints, and areas that may warrant referral for further investigative or field-search evaluation.
Where a Person May Not Go
Behavioral information may suggest possibilities. Terrain analysis helps identify constraints.
A location may look secluded in satellite imagery but be difficult to reach because it requires crossing steep terrain, wet drainage, fences, dense vegetation, unstable ground, or a long off-road carry. Another location may appear farther away by straight-line distance but be easier to access using a familiar road, farm lane, trail, utility corridor, or established pull-off.
This is the value of LiDAR terrain analysis: it does not just help identify places that might be considered. It can help rule down areas that are less practical.
A terrain-based assessment can evaluate:
Steep slopes, ravines, embankments, and difficult terrain crossings
Drainages, wetlands, standing water, and low-lying areas
Road, trail, service-route, and pull-off access
Open exposure from homes, roads, trails, or commonly traveled areas
Fences, gates, property boundaries, and other barriers
The time and physical effort required to travel off-road
Areas that demand more distance, more climbing, more carrying, or greater exposure than the circumstances reasonably support
That shifts a search from a generalized statement— “the subject may have gone somewhere familiar”—to a more useful investigative question:
“Within the locations known or available to this person, which areas were physically reachable, offered practical access, reduced visibility, and fit within the available time window?”
Time, Distance, Speed, and Effort
Every movement event is limited by time.
Investigators may have a known or estimated time window, vehicle information, access points, travel routes, cell-site information, witness statements, or last-known locations. Those facts can be evaluated with actual terrain rather than a simple radius drawn on a map.
Straight-line distance is often misleading.
A point may be geographically close but require a person to descend and climb a ravine, cross a drainage, navigate brush, or travel through exposed terrain. A point that is farther away may be easier to reach using known roads, trails, utility corridors, or familiar access routes.
Cost-distance modeling provides a way to account for these differences. The model can combine distance with slope, terrain barriers, vegetation, drainage, road access, and other documented constraints.
The result is not a prediction of what happened. It is a transparent, case-specific model of what was physically practical.
In a sudden or emotionally driven event, a model may place greater weight on immediate access, short travel time, known routes, vehicle stopping points, and terrain that does not require extensive off-road movement.
In a more planned event, the model may also consider known property connections, repeated travel patterns, familiarity with specific terrain, prior access, and areas where a person may anticipate privacy or reduced visibility.
Research Informs Questions—Not Conclusions
Published behavioral research can help investigators develop stronger questions, but it should not be used as a universal formula.
A recent study of disposed-homicide cases in Queensland found that vehicle transport was common and that many victims in the dataset were located close to roads or tracks after transport. The most common distance from a road or track was 10 meters, and the average was approximately 17 meters.
This does not mean every search should use a fixed roadside buffer. The results reflect one dataset, in one jurisdiction, under particular case conditions. Relationships, planning, terrain, vehicle access, weather, available time, local familiarity, and concealment needs can all change the analysis.
However, the research supports an important search-planning question:
“Which accessible roads, tracks, pull-offs, or trails intersect terrain that also offer practical access, reduced visibility, and plausible stopping locations?”
The FBI has recognized that how and where a victim is left, moved, concealed, or recovered can provide information that helps investigators better understand the circumstances of a case and form investigative questions about offender behavior.
Geographic-profiling methods similarly use probability and spatial information to prioritize areas for investigation. They are intended to support investigative work, not replace case knowledge, field verification, or traditional detective work.
From Data to Search Priorities
A LiDAR-based investigative mapping workflow can include:
Compiling known locations, routes, access points, properties, sightings, and case-specific areas of interest
Creating a LiDAR-derived bare-earth DTM beneath vegetation
Producing Hillshade, elevation, slope, contour, hydrology, and terrain-relief maps
Mapping roads, trails, gates, pull-offs, utility corridors, and potential access points
Evaluating time, distance, speed, terrain effort, visibility, and barriers
Identifying areas that are physically practical and consistent with documented case information
Prioritizing areas for investigator review and appropriate field verification
Producing clear map exhibits and technical documentation
The goal is not to claim that LiDAR identifies a burial location, disposal site, missing person, or criminal act.
The goal is to use physical terrain evidence and known case facts to reduce a large, difficult landscape into smaller, explainable, and defensible search priorities.
LiDAR as Investigative Decision Support
Whether a matter is a cold case, a suspected disposal investigation, or an unresolved missing-person case, LiDAR can help translate a broad landscape into an organized set of terrain-based questions.
It can reveal the shape of the ground beneath vegetation. It can show where a person may travel easily, where they may be slowed or exposed, where terrain creates barriers, and where natural features may deserve closer examination.
When familiarity, access, time, distance, terrain, and human behavior are evaluated together, investigators can move beyond “search everywhere” and toward a more structured question:
What locations were realistically reachable, practical to access, and consistent with the known facts of this case?
That is the role of LiDAR terrain analysis in investigative work: not to replace investigation, but to make the search strategy more focused, transparent, and grounded in measurable terrain conditions.
What’s Next?
Law-enforcement agencies, private investigators, attorneys, and investigative teams can contact ScenePhoto360 to discuss whether LiDAR terrain analysis may support an active, unresolved, or cold-case matter. We can review available case facts, known locations, access routes, terrain conditions, and prior search coverage to determine whether mapping and terrain analysis could help prioritize further investigation or field review. For immediate missing-person emergencies, contact local law enforcement or emergency services first.
About the author
Earl Bakke is a Level II Certified Thermographer and FAA Part 107 pilot with night-operations authorization. Twenty years in law enforcement and crash reconstruction, 450+ thermal inspections, and testimony in criminal and civil proceedings. He founded ScenePhoto360 in Stillwater, Minnesota. Read the full background.
