Expert category
Spatial information and GIS expert witnesses
Mapping and geographic analysis turn a taking into something a fact finder can see. The exhibits a spatial analyst produces are often the most persuasive evidence in a partial taking, and they are built from the agency’s own data.
Scope
The questions this expert answers
What does the taking actually look like
A before and after aerial overlay, the single most useful exhibit in most partial takings.
How much of the site is still buildable
Constraint mapping that nets wetland, floodway and setback out of the gross area.
Where are the comparables
Mapped against the subject, which supports or quietly undermines a sales comparison analysis.
What changed on the ground
Historic imagery establishing the prior condition, which cannot be created after construction starts.
Is the catchment affected
Drive time and access analysis, which matters for retail and service property.
Is the scale honest
Exaggerated vertical scale on a cross section is a standard technique and a standard cross examination.
Selection
What to check before engaging
| Criterion | What to look for |
|---|---|
| Credentials | GIS professional certification or a surveying or planning licence with spatial specialism |
| Data provenance | Can state where every layer came from and when it was captured |
| Accuracy | States positional accuracy rather than implying precision the data does not have |
| Exhibit discipline | One idea per exhibit, built on the real property rather than a generic diagram |
| Litigation record | Has produced exhibits that survived an admissibility challenge |
| Collaboration | Builds exhibits with the testifying expert, who has to defend them |
In practice
Build exhibits with the witness, not for them
An exhibit the testifying expert did not help prepare is one they will hesitate to defend, and hesitation is visible. The spatial analyst supplies the data and the drawing; the expert who will be cross examined on it has to be able to explain how it was made and vouch for its accuracy.
Several of the best exhibits cannot be created after the fact. Dated photographs and imagery of the property before construction are the only record of the prior condition, and once work starts the opportunity has gone.
Listed experts
Experts in this category
The directory is being built. Experts practising in this category can write to editorial@eminentdomainexpertwitness.com. Listing is free, requires evidence of credentials and condemnation experience, and is not sold.
In the meantime, how to find an expert sets out the four routes that reach the same population, and the questions worth asking before you engage anyone.
Questions about this category
Is this a separate expert or part of the appraisal
It can be either. On a straightforward matter the appraiser produces the exhibits. Where constraint mapping or catchment analysis is in dispute, a specialist is worth retaining.
Are animations useful
Occasionally, and they attract admissibility challenges that static exhibits do not. A clear cross section is usually more persuasive and far less contestable.
When should exhibit work start
Earlier than most people do it, because the prior condition record has a deadline that nobody announces.
Related
Other categories
Eminent Domain
The primary category. Valuation and testimony in condemnation and just compensation disputes, covering every discipline a taking can put in issue.
Real Estate Appraisal
Certified appraisers who value property for condemnation rather than for lending, working to USPAP and, on federally assisted projects, the Yellow Book.
Fair Market Value
Opinions on what the market would have paid at the valuation date, under the legal definition rather than a general sense of worth.
Real Estate Damages
Diminution in value, severance damages, cost to cure, lost rent and the loss that remains after a proposed cure.
Land Use and Zoning
Entitlement probability, zoning compliance after a taking, and whether the remainder can still be developed for the use it was valued on.
Land Surveying
Boundaries, easements, encroachments, right of way plans and the survey evidence a partial taking turns on.
The right expert is the one whose field actually covers the dispute
Start from what is contested, not from a list of names. The category pages explain which discipline answers which question.