Built on Public Law, Open to the Public.
ParcelPlanner is an open-source property intelligence platform designed to determine what can legally be built, modified, rented, or developed on a specific parcel of land. The platform translates public land-use law, zoning regulations, municipal ordinances, county regulations, and state law into accessible property intelligence.
ParcelPlanner is designed around a law-first approach. A property goal or development concept cannot be evaluated reliably until the location and governing jurisdiction are established. Once a location is provided, ParcelPlanner identifies the applicable governmental authorities, retrieves the relevant legal and zoning documents, evaluates the applicable requirements, and produces a traceable analysis.
The platform also works in reverse. Instead of starting with a property, a buyer can describe what they want to accomplish and ParcelPlanner can identify jurisdictions where that objective may be legally possible. This creates a Buyer Opportunity Discovery system for people seeking properties that support specific development, rental, housing, or investment strategies.
ParcelPlanner exists to bridge the gap between property ownership, property acquisition, and public law.
The platform is designed to help users answer questions such as:
- What can legally be built on this property?
- Can an accessory dwelling unit be added?
- Can an ADU be used as a rental?
- Can a detached unit, cottage, or other secondary dwelling be developed?
- Can a tiny home be placed on the property?
- Can an existing structure be converted into additional housing?
- What zoning district governs the property?
- What setbacks, lot coverage, density, parking, height, and other restrictions apply?
- Which permits and approvals may be required?
- Which jurisdictions allow the development strategy I want?
- Where should I buy if my goal is to create rental income?
- Is the proposed project physically feasible?
- Is the proposed project financially viable?
ParcelPlanner does not replace legal counsel, planning professionals, surveyors, architects, engineers, or permitting authorities. It is a property intelligence and research decision-support system.
- Law before assumptions.
- Location before legal analysis.
- Official sources before secondary interpretations.
- Traceable citations for legal and zoning findings.
- Current regulations over outdated or superseded regulations.
- Human review for consequential decisions.
- Transparent reasoning and source provenance.
- Public law translated into accessible intelligence.
- Modular architecture that can expand by jurisdiction.
- Open participation without sacrificing source integrity.
- Financial analysis connected to legal feasibility.
- Buyer strategy connected to jurisdictional opportunity.
The Location Module establishes the property or geographic area being evaluated.
Features include:
- Address input.
- Parcel identification.
- Parcel number and property identifier support.
- Municipality identification.
- Township identification where applicable.
- County identification.
- State or province identification.
- Country identification.
- Geographic coordinates.
- Geocoding and reverse geocoding.
- Location validation.
- Property boundary identification where authoritative parcel data is available.
- Location confidence indicators.
- Required location confirmation before jurisdictional analysis begins.
The module must establish a sufficiently precise location before ParcelPlanner presents property-specific zoning or legal conclusions.
The Jurisdiction Discovery Module determines which governmental authorities control the property.
Features include:
- Municipality identification.
- Township identification where applicable.
- County identification.
- State identification.
- Planning authority identification.
- Zoning authority identification.
- Building authority identification.
- Permitting authority identification.
- Applicable special districts.
- Overlapping governmental jurisdictions.
- Jurisdictional boundary verification.
- Authority-to-property relationship mapping.
The module must distinguish between jurisdictions that have authority over land use, zoning, building regulation, permitting, environmental restrictions, and other applicable requirements.
The Government Source Verification Module establishes whether a legal or regulatory source is authoritative and current.
Features include:
- Official government source identification.
- State statute verification.
- State administrative code verification.
- Township ordinance verification.
- Municipal code verification.
- County ordinance verification.
- Zoning ordinance verification.
- Land development regulation verification.
- Unified development code verification.
- Official planning document verification.
- Official zoning map verification.
- Official GIS source verification.
- Court decision verification where applicable.
- Administrative ruling verification where applicable.
- Official legal interpretation verification where applicable.
- Effective date tracking.
- Amendment tracking.
- Superseded regulation detection.
- Source version tracking.
- Citation provenance.
- Source audit history.
ParcelPlanner must prioritize official government legal documents and regulatory sources. Third-party real estate websites, blogs, news articles, social media posts, investor websites, law firm summaries, and other secondary sources must not be treated as authoritative legal sources.
The Zoning Research Module determines the zoning and land-use restrictions applicable to a property.
Features include:
- Zoning district identification.
- Future land-use identification where applicable.
- Permitted-use analysis.
- Conditional-use analysis.
- Special-use analysis.
- Prohibited-use analysis.
- Accessory-use analysis.
- Overlay district analysis.
- Historic district analysis.
- Environmental overlay analysis.
- Flood-related restrictions.
- Lot-size requirements.
- Density requirements.
- Setback requirements.
- Lot coverage requirements.
- Floor-area requirements.
- Floor-area-ratio analysis.
- Building-height restrictions.
- Parking requirements.
- Access requirements.
- Landscaping requirements.
- Open-space requirements.
- Dwelling-unit limitations.
- Rental-use restrictions.
- Development standards.
Each zoning conclusion must be linked to an authoritative source and the applicable legal provision.
The Legal Research Module retrieves and analyzes the laws and legal documents governing a proposed property activity.
Features include:
- State law research.
- Township law research.
- Municipal ordinance research.
- County ordinance research.
- Zoning regulation research.
- Land development regulation research.
- Accessory dwelling unit research.
- Tiny-home regulation research.
- Rental regulation research.
- Short-term rental regulation research.
- Housing-use research.
- Conversion-use research.
- Building and occupancy requirements.
- Permit requirements.
- Approval requirements.
- Special exception requirements.
- Variance requirements.
- Legal definitions.
- Effective-date analysis.
- Amendment analysis.
- Conflict detection between applicable regulations.
- Citation-level legal provenance.
The system must distinguish between what a law explicitly permits, what it conditionally permits, what requires discretionary approval, and what it prohibits.
The Development Opportunity Module converts legal and zoning findings into potential property-development opportunities.
Features include:
- ADU opportunity identification.
- Detached ADU analysis.
- Attached ADU analysis.
- Garage conversion analysis.
- Secondary dwelling analysis.
- Tiny-home opportunity identification where legally permitted.
- Cottage and accessory structure analysis.
- Duplex conversion analysis.
- Multi-unit conversion analysis.
- Additional housing opportunity analysis.
- Rental-income opportunity identification.
- Mixed-use opportunity identification where applicable.
- Development limitation identification.
- Allowed, conditional, prohibited, and uncertain classifications.
- Required approval identification.
Every identified opportunity must be evaluated against the applicable jurisdictional law.
The Buildability Analysis Module determines whether a legally permitted concept can physically fit on the property.
Features include:
- Lot dimensions.
- Lot area.
- Building envelope analysis.
- Setback analysis.
- Maximum building footprint.
- Lot coverage analysis.
- Floor-area analysis.
- Height analysis.
- Parking analysis.
- Access analysis.
- Utility considerations.
- Existing structure analysis.
- Existing improvement constraints.
- Potential development area.
- Development conflicts.
- Preliminary buildability scoring.
The module must clearly distinguish legal permission from physical feasibility.
The Construction Cost Module estimates potential development costs.
Features include:
- ADU cost estimation.
- Tiny-home cost estimation.
- Garage conversion cost estimation.
- Secondary dwelling cost estimation.
- Duplex conversion cost estimation.
- New construction cost estimation.
- Regional cost adjustments.
- Size-based cost modeling.
- Site preparation estimates.
- Utility connection considerations.
- Permit and approval cost considerations.
- Contingency modeling.
- User-supplied construction estimates.
- Cost scenario comparison.
Cost estimates must be presented as estimates rather than guaranteed project costs.
The Rental Income Module evaluates potential income from legally permissible rental opportunities.
Features include:
- Rental income assumptions.
- Monthly rent estimates.
- Annual gross rental income.
- Vacancy assumptions.
- Operating expense assumptions.
- Net operating income.
- Rental strategy comparison.
- Long-term rental analysis.
- Short-term rental analysis where legally permitted.
- Rental restriction detection.
- Income sensitivity analysis.
- User-defined income targets.
Rental analysis must be constrained by the applicable legal and zoning findings.
The Financial Analysis Module evaluates the economic feasibility of a proposed property strategy.
Features include:
- Total project cost.
- Acquisition cost.
- Construction cost.
- Financing assumptions.
- Rental income.
- Operating expenses.
- Net operating income.
- Cash flow.
- Cash-on-cash return.
- Return on investment.
- Cap rate.
- Payback period.
- Internal rate of return where sufficient data is available.
- Scenario analysis.
- Sensitivity analysis.
- Break-even analysis.
- Strategy comparison.
- User-defined financial targets.
Financial conclusions must identify the assumptions used to produce them.
The Strategy Engine converts legal, physical, and financial findings into actionable development strategies.
Features include:
- Goal-based strategy generation.
- Development strategy comparison.
- ADU versus conversion comparison.
- New construction versus conversion comparison.
- Rental-income strategy comparison.
- Cost versus income analysis.
- Legal feasibility scoring.
- Buildability scoring.
- Financial feasibility scoring.
- Risk identification.
- Constraint identification.
- Required approval identification.
- Acquisition recommendations.
- Alternative strategy generation.
- User-defined target optimization.
The Strategy Engine must not recommend a strategy solely because it is financially attractive. Legal feasibility and physical feasibility must be considered first.
The Buyer Opportunity Discovery Module allows users to begin with a goal rather than an existing property.
Features include:
- Natural-language buyer goals.
- Development goal interpretation.
- Rental-income goal interpretation.
- Property-use goal interpretation.
- Housing strategy interpretation.
- ADU goal identification.
- Tiny-home goal identification.
- Secondary dwelling goal identification.
- Jurisdiction screening.
- Municipality comparison.
- Township comparison.
- State comparison.
- Legal compatibility scoring.
- Development opportunity ranking.
- Acquisition criteria generation.
- Property search criteria generation.
- Goal-to-jurisdiction matching.
- Jurisdiction-to-property matching.
- Financial target matching.
- Legal restriction filtering.
Example goals may include:
- "I want to buy a property where I can build an ADU and rent it."
- "I want a detached secondary dwelling."
- "I want to create an additional rental unit."
- "I want to place a tiny home on land."
- "I want to buy property where my development plan is legally allowed."
- "I want to generate a specific amount of monthly rental income."
The module must identify the legal requirements associated with the goal and use those requirements to screen jurisdictions.
The AI Research Assistant Module provides conversational access to ParcelPlanner's property and legal intelligence.
Features include:
- Natural-language questions.
- Property-specific research.
- Jurisdiction-specific research.
- Legal document interpretation.
- Zoning explanation.
- Development scenario analysis.
- Buyer goal analysis.
- Source-aware responses.
- Citation presentation.
- Contradiction detection.
- Uncertainty identification.
- Follow-up questions when required information is missing.
- Human review prompts for consequential findings.
The assistant must not present unsupported legal conclusions as facts.
The Citation and Provenance Module makes every legal and regulatory finding traceable.
Features include:
- Government source citation.
- Document title.
- Government authority.
- Legal section or provision.
- Effective date.
- Amendment status.
- Source publication information.
- Source retrieval information.
- Citation-to-conclusion mapping.
- Source history.
- Superseded-source identification.
- Confidence indicators.
- Research audit trail.
Legal findings without sufficient authoritative support must be identified as unresolved rather than presented as established fact.
The Report Generation Module converts ParcelPlanner research into structured reports.
Features include:
- Property reports.
- Jurisdiction reports.
- Zoning reports.
- Legal research reports.
- Development opportunity reports.
- Buildability reports.
- Financial reports.
- Buyer opportunity reports.
- Strategy reports.
- Source and citation reports.
- Research audit reports.
- Human-review summaries.
- Exportable structured data.
Reports should clearly separate:
- Verified facts.
- Legal requirements.
- Development opportunities.
- Financial assumptions.
- Calculations.
- Unresolved questions.
- Risks.
- Recommendations.
Jurisdiction plugins allow contributors to expand ParcelPlanner into additional municipalities, townships, counties, states, and countries.
Plugins may provide:
- Official zoning sources.
- Official municipal codes.
- Official township ordinances.
- Official county regulations.
- State legal sources.
- Zoning maps.
- GIS sources.
- Planning documents.
- Permit requirements.
- Local development standards.
- Local definitions.
- Local source-verification rules.
Each jurisdiction plugin must identify its authoritative sources and maintain source provenance.
State plugins extend ParcelPlanner's legal research capabilities.
Features may include:
- State statutes.
- State administrative codes.
- Statewide housing regulations.
- Statewide ADU laws.
- Statewide zoning limitations.
- State building requirements.
- State rental regulations.
- State preemption rules.
- State definitions.
- State agency interpretations.
Parcel data plugins may provide authoritative parcel boundaries, identifiers, ownership-related public records where legally available, and geographic information.
GIS plugins may provide official geographic layers relevant to property analysis.
Features may include:
- Zoning layers.
- Flood zones.
- Environmental overlays.
- Historic districts.
- Future land-use layers.
- Parcel boundaries.
- Special districts.
- Infrastructure layers.
Property search plugins may connect ParcelPlanner's legal opportunity criteria to property discovery services.
Property matching must remain subordinate to ParcelPlanner's verified legal and zoning analysis.
Financial plugins may provide supplemental market or financial data for modeling.
Financial data must remain clearly separated from authoritative legal findings.
Document ingestion plugins may process official government legal documents and convert them into searchable, structured legal information.
Notification plugins may monitor official sources for relevant legal changes and alert users when regulations affecting an analyzed property or strategy change.
Export plugins may provide additional report and data formats while preserving citations, provenance, assumptions, and source relationships.
ParcelPlanner follows a location-aware, law-first research process.
The general workflow is:
- The user defines a property, location, or development goal.
- ParcelPlanner establishes the required location.
- ParcelPlanner identifies the governing jurisdictions.
- ParcelPlanner identifies authoritative government legal documents.
- ParcelPlanner verifies source authenticity and currency.
- ParcelPlanner identifies applicable zoning regulations.
- ParcelPlanner analyzes applicable legal requirements.
- ParcelPlanner identifies development opportunities.
- ParcelPlanner evaluates physical buildability.
- ParcelPlanner estimates development costs.
- ParcelPlanner evaluates rental income where applicable.
- ParcelPlanner performs financial analysis.
- ParcelPlanner compares strategies.
- ParcelPlanner identifies risks, restrictions, and unresolved questions.
- ParcelPlanner generates a traceable report.
The Buyer Opportunity Discovery process begins with the buyer's desired outcome.
The workflow should:
- Capture the buyer's natural-language objective.
- Translate the objective into measurable legal and property requirements.
- Identify jurisdictions where the objective may be legally possible.
- Retrieve the applicable official laws and regulations.
- Verify those sources.
- Compare jurisdictional requirements.
- Rank jurisdictions by legal compatibility.
- Identify property characteristics required to pursue the goal.
- Identify matching acquisition opportunities where property data is available.
- Evaluate potential development strategies.
- Estimate costs and income.
- Present the buyer with a sourced opportunity analysis.
This workflow allows ParcelPlanner to answer the strategic question:
Where should I buy to legally accomplish what I want to do?
ParcelPlanner's legal and zoning intelligence must be based on authoritative public sources.
Preferred sources include:
- State statutes.
- State administrative codes.
- Township ordinances.
- Municipal ordinances.
- County ordinances.
- Zoning ordinances.
- Land development regulations.
- Unified development codes.
- Official planning documents.
- Official zoning maps.
- Official GIS data.
- Court decisions.
- Administrative rulings.
- Official governmental legal interpretations.
- Other official government legal documents.
Third-party summaries must not replace the underlying legal authority.
ParcelPlanner should identify the actual controlling provision whenever possible rather than relying on a secondary description of the law.
ParcelPlanner must:
- Identify the applicable jurisdiction before property-specific legal analysis.
- Identify the applicable law before making a legal finding.
- Verify the current status of relevant regulations.
- Identify effective dates.
- Detect superseded provisions where possible.
- Preserve source provenance.
- Distinguish mandatory requirements from discretionary approvals.
- Distinguish permitted, conditional, prohibited, and unresolved uses.
- Identify conflicts between applicable legal provisions.
- Identify uncertainty when the source material is insufficient.
- Avoid unsupported legal conclusions.
- Present findings as decision-support information rather than legal advice.
ParcelPlanner is designed to keep people in the decision loop.
Human review should be encouraged when:
- The legal authority is ambiguous.
- Regulations conflict.
- A discretionary approval is required.
- A variance may be required.
- A special exception may be required.
- A property has unusual restrictions.
- The proposed project has significant financial consequences.
- The source material is incomplete.
- The law has recently changed.
- A governmental authority must provide a final determination.
ParcelPlanner should make uncertainty visible rather than hiding it.
ParcelPlanner should maintain a clear relationship between:
- Property.
- Location.
- Jurisdiction.
- Government authority.
- Legal document.
- Legal provision.
- Zoning rule.
- Development opportunity.
- Buildability finding.
- Financial assumption.
- Strategy.
- Recommendation.
Users should be able to trace important conclusions back to the authoritative source from which they were derived.
ParcelPlanner must be designed so that geographic expansion does not require rewriting the core analytical system.
The core system should remain jurisdiction-neutral wherever possible.
Jurisdiction-specific requirements should be implemented through optional modules and plugins.
This allows contributors to expand ParcelPlanner from one municipality or state to additional jurisdictions while preserving the same core research and analytical workflow.
ParcelPlanner should make its reasoning understandable to users.
The platform should identify:
- What information was used.
- Which jurisdiction supplied the information.
- Which legal document supports the finding.
- Which provision supports the finding.
- What assumptions were made.
- What remains uncertain.
- What additional information is required.
- Which conclusions are legally verified.
- Which conclusions are analytical estimates.
- Which recommendations require human confirmation.
ParcelPlanner should minimize unnecessary collection of personal information.
The platform should support:
- Data minimization.
- User-controlled property research.
- Secure handling of saved research.
- Access controls.
- Protection of sensitive property information where applicable.
- Clear separation between public legal information and private user information.
- User control over saved research and generated reports.
ParcelPlanner is intended to make public land-use law more accessible.
The project encourages contributions that:
- Expand jurisdictional coverage.
- Improve legal source verification.
- Improve zoning analysis.
- Improve property intelligence.
- Improve accessibility.
- Improve transparency.
- Improve source provenance.
- Improve financial modeling.
- Improve buyer opportunity discovery.
- Reduce dependence on proprietary property intelligence systems.
Contributions should preserve the project's law-first, source-grounded approach.
- Fully AGPL-3.0+ compliant system
- Copyleft enforced for network deployments
- Required attribution:
- Roxanne Ardary
- https://www.roxanneardary.com/
- Specification Branding License (SBL)
- Attribution-free commercial deployment
- Pricing based on scale, usage, and deployment scope
- https://roxanneardary.com/parcelplanner/
ParcelPlanner is released under the GNU Affero General Public License v3.0 or later (AGPL-3.0+).
By contributing to this project, you agree that your contributions will also be released under this license.
Please note the following:
- All contributions must comply with the AGPL-3.0+ terms.
- Under Section 7 of the license, all redistributions, forks, and derivative works must preserve attribution to:
Roxanne Ardary and roxanneardary.com. - ParcelPlanner specificiations are free to use with attribution. A Specification Branding License can be negotiated upon request.
- The project's notice.md file tracks attribution requirements and contributor acknowledgments.
Any update that adds new contributors or modifies attribution should also updatenotice.md. - When submitting a pull request, ensure that any new files maintain the attribution headers where applicable.
- Network-deployed versions of this software must also remain fully AGPL-3.0+ compliant, including exposure of source code modifications when applicable under the license.
For full legal details, please refer to the AGPL-3.0+ license and the project's notice.md file.
Open Arsenal Hub
https://gitlab.com/Roxanne_Ardary/open-arsenal-specs