BricsCAD: How to use GSI DEM data to generate terrain (TIN) and contour lines?

juliette1699
juliette1699
edited 8:48AM in Importing and exporting files

Hi everyone,

I’m working with several civil engineering and surveying clients in Japan, and almost all of them rely heavily on the Geospatial Information Authority of Japan (GSI) maps — especially the basic map data and DEM (elevation) data.
https://maps.gsi.go.jp/vector/#13.002/35.498249/133.172208/&ls=vpale&disp=1&d=l

image.png

The clients are using two different datasets from the Geospatial Information Authority of Japan (GSI):

  • 2D Basic Map Information: SFC / GML / Shapefile
  • 3D Elevation Data: DEM exported as XYZ → converted to CSV (NEZ format for BricsCAD)

They need to generate both:

  • clean 2D base map outlines (from SFC/GML), and

3D terrain / TIN surfaces + contour lines (from DEM/XYZ)

++++++
Recently, at least four different companies contacted us asking:

  • How to bring GSI map data into BricsCAD
  • How to generate clean contour lines (white-background base maps)
  • How to create terrain from DEM data inside BricsCAD

After researching the best possible workflow, it seems the only practical way right now is:

  1. Download SFC / GML or DEM (XYZ) from GSI
  2. Convert it using QGIS (to DXF / SHP / CSV-NEZ)
  3. Import the converted data into BricsCAD and build TIN surfaces / contours

 

image-1d7b567a5440b8-cca4.jpg


However…
For users who have no GIS experience, QGIS is extremely difficult.
Even simple tasks like loading DEM, exporting XYZ, or converting layers require too many steps.
Everyone is frustrated that they “must” learn an additional GIS software just to use GSI data in BricsCAD.

So my questions are:

  1. Why can’t BricsCAD import DEM or GSI map formats directly?
  2. Is there any plan to support GSI formats natively (SFC, GML, DEM, XYZ, GeoTIFF)?
  3. Are there plugins or add-ons planned for Japan users to load GSI maps directly inside BricsCAD?
  4. For Japanese civil/survey customers, GSI maps are essential — is Bricsys considering simplifying this workflow?

I think many users would benefit from a smoother, more integrated workflow.
Even a simple “GSI Import” tool or an automatic DEM → TIN conversion feature would solve most pain points.

If anyone has alternative workflows, recommended plugins, or knows about Bricsys development plans, please share.
Any information would be greatly appreciated.

Thanks!

Comments

  • juliette1699
    juliette1699

    Below is what ChatGPT answered me：

    ✅ 1. Why can’t BricsCAD import DEM or GSI map formats directly?

    ✔ Technical Reason (Core Issue)

    BricsCAD is fundamentally a CAD-based vector engine, while most datasets provided by the Geospatial Information Authority of Japan (GSI) are GIS raster formats or GIS-structured vector formats, such as:

    • DEM / Grid Elevation Models (raster-based)
    • GeoTIFF Elevation Models
    • GSI-specific GML / XML schemas
    • SFC (基盤地図情報専用フォーマット)

    CAD engines like BricsCAD, AutoCAD, MicroStation are not designed to parse, render, or analyze GIS raster grids.
    Raster DEM data must be sampled, converted, or vectorized before CAD systems can process them.

    ✔ Simple Explanation

    DEM = raster grid (pixels with elevation)
    CAD = vector geometry (lines, points, surfaces)
    Raster → Vector conversion is required.

    Because of this, BricsCAD Civil Tools focuses on:

    • Points (NEZ / XYZ)
    • 3D Polylines
    • TIN Surfaces
    • Contours

    These are vector-based elements suitable for CAD design workflows — not raster DEM models.

    Conclusion:
    BricsCAD does not import DEM directly not because it is incapable, but because it does not include a built-in GIS raster engine, which would require fundamentally different technologies.

    ✅ 2. Is there any plan to support GSI formats natively (SFC, GML, DEM, XYZ, GeoTIFF)?

    ✔ Current Status (Reality Check)

    As of today, Bricsys officially supports:

    • ✔ GML / SHP via GISIMPORT
    • ✔ XYZ (after converting into CSV-NEZ)
    • ✘ SFC (Japan-specific basic map format)
    • ✘ DEM (Grid Elevation Models)
    • ✘ GeoTIFF

    Regarding official development plans:

    • The Bricsys public roadmap does not mention native GSI format support.
    • Civil Tools development is focused on global standards such as IFC, LandXML, SHP, and general GIS formats.
    • GSI formats are a regional specialization and require dedicated engineering effort.

    ✔ Technically possible, but requires GIS infrastructure

    To support GSI formats directly, BricsCAD would need:

    • A parser for GSI’s unique GML schema (structure differs from general GML)
    • A raster DEM engine to handle elevation grids
    • Built-in support for GSI API / 地理院タイル
    • Automated DEM → TIN surface conversion capabilities

    This is a significant development project and is currently not officially planned.

    ✅ 3. Are there any plugins or add-ons planned for Japan to load GSI maps directly inside BricsCAD?

    ✔ No official plugin exists at the moment

    Bricsys does not currently provide:

    • “GSI Import Tool”
    • “Japan Map Loader”
    • “DEM → TIN automatic converter”
    • “SFC/GML auto-conversion wizard”

    ✔ Third-party situation

    Currently in Japan:

    • No dedicated BricsCAD plugins for GSI map import exist.
    • AutoCAD users face the same situation — they typically rely on:
      • QGIS
      • FME
      • Other GIS preprocessors

    So this is an industry-wide limitation, not unique to BricsCAD.

    ✔ However, potential future directions exist

    If enough Japanese users request it, Bricsys could consider:

    • A plugin that connects directly to GSI Map Tiles API
    • Native parsing of SFC / GML (Japan-specific schema)
    • A built-in DEM → TIN surface generator
    • Direct import of XYZ elevation models without conversion
    • Automated contour generation from DEM

    You can help accelerate this by creating feature requests and gathering user feedback from Japan.

    ✅ 4. For Japanese civil/survey customers, GSI maps are essential — is Bricsys considering simplifying this workflow?

    ✔ Current Situation

    Japan is one of the strongest growth regions for BricsCAD in Asia.
    Bricsys is increasingly aware of:

    • The importance of GSI datasets
    • The reliance of Japanese civil/survey workflows on DEM, SFC, GML
    • The difficulty of requiring QGIS as a preprocessing tool

    However:

    • There is no official announcement about integrating GSI workflows
    • There is no confirmation that DEM or GeoTIFF import will be supported
    • The recommended method is still QGIS preprocessing → BricsCAD Civil

    ✔ Possible Future Enhancements (realistic and useful)

    If Bricsys invests in Japan-specific functionality, the following features would be extremely beneficial:

    • Native GSI map connection (地理院タイル API)
    • One-click import of GSI DEM → automatic TIN creation
    • SFC/GML automatic parser for Japanese Basic Map Information
    • Automated contour generation directly from DEM
    • XYZ (elevation points) direct import without conversion
    • Full integration of GSI datasets with Civil Tools

    These features would dramatically reduce the learning burden for users and remove the dependency on QGIS.

    ✔ Community pressure matters

    The more Japanese users and partners raise this requirement:

    • On the BricsCAD Forum
    • Through feature-request channels
    • Through Japan resellers and distributors

    …the more likely Bricsys will allocate engineering resources to GSI support.

  • juliette1699
    juliette1699

    Me：
    How to use GSI DEM data to generate terrain (TIN) and contour lines?

    Google AI modes：
    To generate a terrain model (TIN) and contour lines from GSI (Geospatial Information Authority of Japan) DEM data, follow these steps using standard GIS software like ArcGIS or QGIS. 1. Obtain and Prepare GSI DEM Data

    • Download: Access the data from the GSI Fundamental Geospatial Data portal.
    • Format: GSI DEM is typically provided in a grid-based raster format (e.g., 5-meter or 10-meter mesh). Some Antarctic datasets may be available in Shapefile format.
    • Import: Add the DEM raster layer to your GIS project. 

    2. Generate Contour LinesGenerating contours is usually the first step, as they can be used to build the TIN. 

    • In QGIS: Go to Raster > Extraction > Contour. Set the "Contour interval" (e.g., 10m) and run the tool to create a vector line layer.
    • In ArcGIS: Use the Contour (Spatial Analyst) tool. Specify the input raster and the desired interval.
    • Smoothing: For a more natural look, apply a smoothing level to reduce jagged edges caused by the grid resolution. 

    3. Generate a TIN (Triangulated Irregular Network) A TIN provides a more flexible 3D surface representation than a grid. 

    • From Contours (Recommended):
      • In ArcGIS: Use the Create TIN (3D Analyst) tool. Use the generated contour lines as "Input Features" and set their height field as the source. Select Soft_Line or Hard_Line for the edge type to maintain terrain features.
      • In QGIS: Use the TIN Interpolation tool from the Processing Toolbox. Add your contour layer and select the elevation attribute.
    • Directly from Raster: Some tools allow direct conversion from DEM to TIN by extracting mass points from the grid cells, which are then triangulated based on a specified vertical tolerance. 

    Summary of Tools

    Task 

    ArcGIS Tool

    QGIS Tool

    Contours

    Contour (Spatial Analyst)

    Contour (Raster Extraction)

    TIN

    Create TIN (3D Analyst)

    TIN Interpolation

  • juliette1699
    juliette1699

    Me：
    BricsCAD generate contour lines?

    Google AI modes：
    BricsCAD (Pro/BIM/Mechanical) generates contour lines from TIN surfaces using the TINEXTRACT command. Users can define intervals for major/minor contours, select layers, and generate 2D or 3D lines. It also supports creating TIN surfaces from 3D points, polylines, or raw survey data. This video demonstrates how to create a TIN surface from contour data:

    image-c2780b3fb31af8-63cf.jpeg

    34s

    image-06a7dbf7ba7058-aac7.png

    Key Methods for Generating Contours in BricsCAD:

    • TINEXTRACT Command: Extracts contours directly from an existing TIN surface, allowing control over major/minor intervals.
    • SITE Command: Creates a topographical surface (TIN) from 3D entities (points/polylines) which can then be used to generate contours.
    • Spatial Manager for BricsCAD: A third-party tool that generates 2D/3D contours, labels them automatically, and organizes them by layer.
    • TheoContour: A BricsCAD application that generates surfaces and contours from simple point entities.
    • Point Cloud Data: The POINTCLOUDPROJECTSECTION command creates contours from 3D point clouds. 

    Tips for Better Contours:

    • V24+ Updates: BricsCAD V24 introduced enhanced functionality to create more accurate TIN surfaces directly from existing contour data, minimizing flat areas.
    • Visualization: Use the Properties panel to toggle the display of contours, triangles, and boundaries on a TIN surface.
    • Editing: TIN surfaces can be merged using the TINMERGE command. 

    https://www.youtube.com/watch?v=ADgrLB3JMLo

  • juliette1699
    juliette1699
    image.png

    How about other software options?