Octo for survey drafting and legal descriptions
The plan, the sheet with its title block, the coordinate table, the area schedule and the draft legal description can all come from a script that reads the same DXF used in the calculation. Octo generates them, checks declared area against calculated area, finds open polylines and adjoining boundaries that don't close, and delivers everything for review. The signature, the ART or TRT and the filing with the city or the land registry stay with the licensed professional.
Six possible deliverables, drawn from the research. All of them start from the drawing the office already has, run in the client's environment and go to review by the person who signs.
One description per lot, with vertices, azimuths, distances, adjoining owners, area and perimeter taken from the DXF, in the registry template the person in charge approved.
Deliverable: text drafts + check CSVOne sheet per block or per lot, with a viewport at scale, the office title block filled in from attributes, the area schedule and the coordinate table.
Deliverable: DXF, DWG and PDF per sheetNon-standard layers, wrong units, open polylines, duplicate vertices, self-intersections, unnumbered lots and declared areas that don't match the calculated ones.
Deliverable: issues report, file untouchedLots, streets, green and institutional areas summed against the parent tract, with percentages, to compare with what the municipal law requires for the subdivision.
Deliverable: schedule checked by sumParts that add up to the original area, with no overlap; a unified perimeter when merging; a description of the remainder. The split itself is the technician's proposal.
Deliverable: descriptions of the parts and sum checkTopograph, DataGeosis and Posição save DXF, DWG and point files. Octo compares the program's description with the one generated from the drawing, vertex by vertex.
Deliverable: list of differences for the technicianThe same Octo cycle, applied to plans and legal descriptions. Each arm has a narrow role; the one who signs, issues the ART or TRT and files is the licensed professional.
CAD and surveying software in use, the actual layer standard, title block, each registry's description template and where the calculation DXF lives.
Reference system, the RRCM local plane if there is one, tolerances, the approved schedule, rural adjoining owners and the municipal law's ratios.
Legal descriptions carry names, ID numbers and registry numbers: they stay in the client's environment and are assessed with the client (LGPD, Brazil's data protection law) before going to any external service. External executables only if installed and verified.
Plain ezdxf, ezdxf with ODA File Converter or scripted CAD; DXF as the single source; check PDF from ezdxf or plotted in CAD.
Python with a dry-run mode, a check report and a non-zero exit code when there are open issues.
Compares with lots already registered: same area, same text, same adjoining owner. Checks by content, not by the absence of errors.
A folder with drafts, sheets, PDFs and SHA-256 for the technical lead. Nothing is sent to the city or the registry.
The approved template, tolerances, ezdxf and converter versions and the result of each lot generated.
Octo works in a support role. It does not sign plans or legal descriptions, does not issue an ART or TRT, does not decide a disputed boundary and does not file with public agencies: that belongs to the licensed professional.
The criteria Octo uses to choose. Scripted AutoCAD is covered in the Autodesk field and is not repeated here.
| Task | Path | Notes |
|---|---|---|
| Read and check DXF | ezdxf.recover.readfile, ezdxf audit | Read only; .rec.dxf copy if requested |
| Read or write DWG | ODA File Converter, directly or through ezdxf.addons.odafc | Converter license to be confirmed |
| Legal description per lot | Python on the DXF (ezdxf.math) | Template approved by the person in charge |
| Area and coordinate schedules | TablePainter in the layout | Plain lines and text, no ACAD_TABLE |
| Standard title block | Block with attributes + add_auto_attribs | Responsible party, registration and ART/TRT left blank |
| Check PDF | ezdxf draw --backend mupdf -l LAYOUT | Fidelity to CTB and SHX to be confirmed |
| PDF for signing | Scripted plotting in AutoCAD or BricsCAD | The office's plot style |
| Headless CAD | BricsCAD /automation /B script.scr (Windows) | The script must close the program |
| Cross-check with Brazilian software | Compare exported DXF and text | No public API found |
| Rural property for SIGEF | Sister georeferencing page | Geodetic coordinates |
Three steps. Each one only makes sense after the previous one has shown results in your office.
A proposal, not a promise
The client's drawing and the office's own go through a check that changes nothing and says what is wrong.
Legal descriptions and tables come from the same DXF, in the approved template, and every change to the drawing regenerates everything.
Sheets per block with title blocks, DWG and PDF, with SHA-256 of what was reviewed, ready for signature.
Every point below has a source published by the responsible agency (Planalto, INCRA, IBGE, ANAC, DECEA), by the vendor or by the project. ABNT standards appear only by number and title. The sources are in the next section.
4
points with a published source, each with its reference shown alongside.
odafc add-on, which calls the installed ODA File Converter. The documentation warns that calling an external executable is a security risk.Source: PyPI and ezdxf documentationOcto prepares everything, but it does not sign. The document of record stays with whoever is accountable for it.
Surveys, calculates, organizes and produces the documents: spreadsheets, reports, drawings and draft legal descriptions.
Deliverable: material ready to checkThe licensed professional checks what Octo delivered before signing. If something doesn't add up, it goes back to Octo with the correction.
Step: checked by the person who signsOcto does not sign. Designs, technical reports, ART/RRT, statements of account and any official document are still signed by the licensed professional at the company or agency: here, the surveying or cartographic engineer with an ART filed with CREA, or the surveying technician with a TRT filed with CRT; for rural properties, the professional accredited by INCRA, who submits to SIGEF.
Signature: licensed professional, with ART or TRTLaws, documentation and vendor pages used in the research, consulted on Oct 31, 2026.
The assessment starts with a subdivision or a parcel split your office has already delivered, without touching the original. You get a proposal for what can be generated and checked by script, tested on lots already registered, and you decide with that in hand.