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Octo × Terrain PT Request an assessment

Octo for terrain modeling

The volume calculation runs on its own. The base, the density and the signature are yours.

Cut and fill volumes, contour lines and stockpile measurement are differences between two surfaces, and almost all of it runs in batch with GDAL, PDAL and Python, checked against the program the office already uses (Carlson, Civil 3D, Topograph, DataGeosis). Octo builds the scripts, runs them with two grid spacings, draws the cut-and-fill map and points out what doesn't add up. Base, breaklines, tolerance, density and the measurement with an ART stay with the technical lead.

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Fictional surface of a hill drawn by ten contour lines at one-meter intervals, with the 800 and 805 meter index contours thicker and labeled, a profile axis crossing the hill, and on the left a terminal that generates the contours with gdal_contour and a cut-and-fill summary 800 805 ▲ 809.6 AA' $ gdal_contour -a cota -i 1 \ mdt_q07.tif q07.geojson index and intermediate contours cut and fill per grid spacing difference map WARNING when spacing changes the volume PROFILE A-A' grade 806 OCTO × TERRAIN INTERVAL 1 m T-04
Illustration: surface drawn by contour lines, with labeled index contours and a profile axis; fictional data.
GDAL3.13.3version of Aug 18, 2026
PDAL2.10.2version of Jun 12, 2026
Carlson 202613.1on IntelliCAD 13.1; supports AutoCAD 2026
Sources14listed at the end of the page
01

What Octo does in terrain modeling.

Six possible deliverables, drawn from the research. All of them work on a copy of the field files, and all of them go to review by the person who signs the measurement.

DTM and TIN checked

Reads the points and finds duplicates in plan, break codes that didn't become breaklines and gaps in coverage before triangulating.

Deliverable: surface with a list of issues

Cut and fill with a map

Difference between original and current ground at two grid spacings, a color map with a neutral band and daylight line, and a report with warnings.

Deliverable: volumes + map + report

Batch contours to DXF

Index and intermediate contours on the client's layers, labels aligned and never upside down, short segments discarded, one sheet per DTM.

Deliverable: DXF per sheet + summary

Profiles and sections

Terrain sampled station by station, cut and fill areas per section, volumes by average end area and a cumulative volume table.

Deliverable: tables and drawing for checking

Stockpiles every month

The flight's point cloud becomes a grid per stockpile, volume over the chosen base, mass by the approved density and reconciliation with the recorded movements.

Deliverable: history per stockpile + open items

Cross-check

The same calculation in the office program and in the open script, with the same boundary. A difference above tolerance becomes a question, not an adjustment.

Deliverable: side-by-side table of the two calculations
02

Eight arms, one terrain measurement.

The same Octo cycle, applied to terrain modeling. Each arm has a narrow role; the ones who choose the base, approve the density and sign the measurement are people.

  1. Discovery

    Surveys what already exists

    Surveys and dates, equipment, coordinate system, the office program and its version, volume reports already issued.

  2. Data

    Pins down references

    Horizontal and vertical reference frames, the boundary of each area, field codes, approved densities and the measurement history.

  3. Security

    Looks after access and data

    Reads the field files and calculates on a copy. Private areas, tonnage and shipments are the client's confidential information and don't go to an external service without agreement.

  4. Architecture

    Chooses the path

    The office program, GDAL, PDAL or Python; grid or TIN; floor or toe as the stockpile base; DXF, GPKG or a report as the deliverable.

  5. Development

    Writes the script

    Dry run, two grid spacings, warnings and exit codes, with the source of each syntax noted in the file.

  6. Review

    Checks against an accepted calculation

    Compares with the office program or with an old measurement already accepted, by the numbers and the map, not by the absence of errors.

  7. Release

    Delivers to the agreed folder

    Only with the lead's OK, it writes DXF, report and history where the team works. Nothing goes to invoicing or inventory without a person.

  8. Documentation

    Records what applies to your project

    Parameters, versions, base method and the result of each measurement, so next month's is comparable.

Octo works with read access and in a support role. It does not sign surveys, does not issue measurements for payment and does not adjust inventory: that belongs to a licensed professional, with an ART or TRT.

03

Every task, its own path.

The criteria Octo uses to choose. Always with the documentation for the installed version and a check against a calculation already accepted.

TaskPathNotes
Volume between two point surveysSciPy Delaunay + grid, or TIN to TIN in CADTwo spacings and the same boundary
Volume between two drone DTMsgdal_calc --calc="B-A" --extent=intersectSame vertical reference
Cut-and-fill mapgdaldem color-relief with a diverging paletteNeutral band equal to the accuracy
Daylight linegdal_contour -fl 0 on the difference gridVector for the drawing
Batch contour linesgdal_contour or gdal raster contourThe client's contour interval
DXF contours with layers and labelsezdxf over the GDAL outputThe client's drafting standard
Grid from a point cloudPDAL writers.gdalClasses listed, not negated
Stockpile volumeStockpile grid minus the base (floor or toe)Method recorded on every row
Volume surface in Civil 3DAPI: AddTinVolumeSurface and StatisticsDetails in the Autodesk case
04

From one-off checks to monthly measurement.

Three steps. Each one only makes sense after the previous one has shown results on your survey team.

A proposal, not a promise

1 Today

Second opinion on volume

You send the original ground, the current one and the boundary; Octo redoes the calculation by script and puts it next to your program's number.

  • Volume at two grid spacings
  • List of duplicate points and missing breaklines
  • Cut-and-fill map for the meeting
Gain: errors show up before the measurement
2 Next

Drafting batches

Contours, profiles and sections for many sheets come out in the client's standard, with a summary per sheet for review.

  • Index and intermediate contours in DXF
  • Sections and cumulative volumes per segment
  • Summary of elevations and discarded segments
Gain: the drafter reviews a sample instead of redoing sheets
3 Later

Monthly measurement, monitored

Stockpiles and work fronts measured every month with the same method, a comparable history and reconciliation with the client's system.

  • Grid per stockpile from the flight
  • History with the base method on every row
  • Open items for the person in charge, with no automatic adjustment
Gain: measured inventory matches recorded inventory
05

Confirmed by a source.

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.

ConfirmedContours and differences with GDAL
gdal_contour accepts -i, -fl, -off, -3d and polygons with -p; the new CLI has had gdal raster contour since 3.11. gdal_calc has had --extent=intersect since 3.3 and depends on the Python bindings.Source: gdal.org, gdal_contour, gdal raster contour and gdal_calc pages
ConfirmedThe class filter trap in PDAL
In filters.range, ranges on the same dimension are combined with OR and on different dimensions with AND. Two negations on the same dimension let everything through; the example lists the classes to keep.Source: pdal.io, filters.range
ConfirmedThe method changes the volume
Carlson's tutorial calculates the same stockpile by five methods (stockpile, layers, two grids, two TINs, sections) and gets fills from 3,264.22 to 3,265.59 cubic yards.Source: Carlson, "Calculate Volumes By 5 Methods" (2022 manual)
ConfirmedCivil 3D exposes cut and fill in its API
The TIN volume surface is created with AddTinVolumeSurface (base and comparison) and returns CutVolume, FillVolume and NetVolume in Statistics.Source: Autodesk, Civil 3D developer's guide (2023)
06

What Octo does, and what stays with you.

Octo prepares everything, but it does not sign. The document of record stays with whoever is accountable for it.

Octo prepares

Surveys, calculates, organizes and produces the documents: spreadsheets, reports, drawings and draft legal descriptions.

Deliverable: material ready to check

Your team checks

The 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 signs

Who signs

Octo 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 TRT
07

Sources.

Documentation from open-source projects and vendors used in the research, consulted on Oct 31, 2026.

This month's volume, checked before the meeting.

The assessment starts with a measurement your team has already done: the original ground, the current one and the accepted number. You get the same calculation by script, the map and the list of what can be automated, and you decide with that in hand.

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