LandXML Import

LandXML is the international standard for exchanging civil engineering design data. SiteView parses LandXML alignment files to extract full horizontal and vertical geometry — straights, circular arcs, clothoid spiral transitions, constant grades, and parabolic vertical curves — giving you a precise centreline definition for chainage marking, cross-sections, and conformance checking.

What Is LandXML?

LandXML is an open XML-based file format designed for exchanging civil engineering and survey data. It is widely used across the road and rail construction industry to share design geometry between different software packages and between design teams, surveyors, and contractors.

A LandXML file can contain one or more <Alignment> elements, each defining a road centreline, railway track, or corridor path. Within each alignment, the <CoordGeom> element describes the horizontal geometry (the plan view) and the <Profile> element describes the vertical geometry (the elevation profile along the centreline).

ℹ️ Did you know?

LandXML is not the same as a DXF drawing. A DXF file contains graphical linework — polylines, arcs, and text drawn on layers. A LandXML file contains mathematically defined geometry with precise parameters for every curve and transition. This means SiteView can compute exact positions, bearings, elevations, and grades at any chainage along the alignment.

Uploading a LandXML File

To import an alignment from a LandXML file:

1. Open a site in SiteView and navigate to the Alignments section.
2. Click Import Alignment to open the upload modal.
3. Select LandXML (.xml) as the source format (this is the default).
4. Choose your .xml file using the file picker.
5. Click Import to upload and parse the file.

SiteView parses the file on the server, extracts all <Alignment> elements, and creates a separate alignment record for each one. If your LandXML file contains multiple alignments (for example, a mainline and several ramps), all of them are imported in a single upload.

After import, SiteView generates a polyline representation sampled at one-metre intervals and stores it as a GeoJSON LineString for rendering on the CesiumJS globe. The map automatically flies to the imported alignment's bounds so you can see it immediately.

Horizontal Geometry

The horizontal alignment defines the path of the centreline in plan view. SiteView supports all three standard horizontal element types found in LandXML files:

Straights (Lines)

A straight segment between two points. Defined by a start coordinate and an end coordinate. SiteView computes the length and bearing from these points.

Circular Arcs (Curves)

A curved segment defined by a start point, centre point, end point, radius, and rotation direction (clockwise or counter-clockwise). SiteView calculates the arc length from the subtended angle and can compute the exact position and tangent bearing at any point along the curve.

Clothoid Spirals

A transition curve where the radius changes linearly along the length — from infinite radius (a straight) to a finite radius (joining a circular arc), or vice versa. Clothoid spirals are the standard transition type used in road and rail design because they provide a smooth, continuous change in curvature that is comfortable for drivers and safe for vehicles.

SiteView implements a Fresnel integral series expansion to compute exact positions along clothoid spirals, providing sub-millimetre accuracy with ten series terms. Both entry spirals (straight-to-curve) and exit spirals (curve-to-straight) are supported.

💡 Tip

Most road alignments follow a pattern of straight-spiral-curve-spiral-straight for each bend. The spirals provide a gradual transition so that curvature does not change abruptly. If your alignment file only contains straights and curves without spirals, SiteView handles that correctly too — it just means the alignment has sharp transitions at tangent points.

Vertical Geometry

The vertical alignment defines the elevation profile along the centreline. SiteView supports the two standard vertical element types from LandXML <Profile> and <ProfAlign> elements:

Constant Grades

A linear slope between two vertical points of intersection (VPIs). Defined by a start elevation, end elevation, and grade percentage. Grades are stored as percentages — a 3% grade means 3 metres of rise per 100 metres of horizontal distance.

Parabolic Vertical Curves

A smooth parabolic transition between two different grades, centred on a VPI. Defined by the VPI chainage, VPI elevation, entry grade, exit grade, and curve length. These are used at crests and sags to provide a smooth transition that is safe for sight distances and comfortable for road users.

SiteView parses the <PVI> and <ParaCurve> elements from the LandXML profile and converts them into a sequence of grade and parabolic curve segments. This allows the system to compute the design elevation and design grade at any chainage along the alignment.

ℹ️ Did you know?

If your LandXML file does not include a <Profile> element, the alignment is imported with horizontal geometry only. Chainage markers will still display on the map, but elevation and grade information will not be available for cross-sections or conformance checking.

Coordinate System Detection

SiteView automatically detects the coordinate system used in your LandXML file. It checks the <CoordinateSystem> element for references to:

• MGA2020 — Map Grid of Australia zones 49 through 56
• NZTM2000 — New Zealand Transverse Mercator
• WGS84 — World Geodetic System (geographic coordinates)

If no <CoordinateSystem> element is present, SiteView falls back to auto-detection based on the coordinate value ranges. Grid coordinates are converted to WGS84 longitude/latitude for rendering on the CesiumJS globe.

Supported Schema Versions and Sources

SiteView parses the core alignment elements (<Alignment>, <CoordGeom>, <Profile>) that are consistent across LandXML schema versions. The parser is designed to handle files from common civil engineering software including:

• Autodesk Civil3D — the most widely used civil design package in Australia
• 12d Model — popular for road and rail design in Australia and New Zealand
• Bentley OpenRoads Designer — used for infrastructure design globally
• Trimble Business Center — survey and design software from Trimble
• Other packages — any software that exports standard LandXML alignment data

⚠️ Watch out!

SiteView focuses on alignment geometry (centreline path and vertical profile). Other LandXML elements such as cross-section templates, superelevation data, pipe networks, and surface TINs are not imported. If you need to overlay a design surface on the map, upload the design as a DXF file through the Design Surfaces feature.

After Import

Once your LandXML alignment is imported, you can:

• View chainage markers along the centreline on the 3D globe
• Generate cross-sections at any chainage to compare survey against design
• Run conformance checks to verify the as-built surface matches the design within tolerance
• Toggle the alignment visibility on and off in the layer control panel
• Delete the alignment if it is no longer needed

💡 Tip

If you do not have a LandXML file but you do have a DXF design surface with a centreline polyline, you can create a simplified alignment from a DXF layer instead. The DXF approach does not capture curve geometry, but it works well for preliminary checks or when a full LandXML export is not available.