Alignment & chainage

👤 Roles — Can access: Mobile User · Can edit settings: Mobile User

Overview

Mark a linear feature as a project alignment to enable chainage and offset calculations for features captured against it — useful for road, rail, pipeline, and corridor surveys.

ℹ️ App version: Soarvo Mobile 0.0.134+.

Three Things Alignment Enables

Map chainage and offset display — a widget at the bottom of the map shows your current chainage and offset from the alignment.
Chainage markers — the alignment is automatically styled with distance markers along its length.
Chainage default codes — attribute codes that calculate chainage and offset for any feature.

Marking a Feature as Alignment

In the mobile app, select an existing linear feature.
Tap the ⋮ context menu on its sheet.
Select Use as Alignment.

To unmark, repeat and select Remove as Alignment.

Configuring Units

Chainage defaults to metres. To use miles and yards (e.g. 1M 13Y):

Edit the alignment feature type in the web portal.
Add a radio attribute Units with option MilesAndYards (optionally also Metres as default).
Set the alignment feature's Units to MilesAndYards.

Configuring Start Chainage

If the alignment doesn't start at 0, add a numeric attribute StartChn to the feature type. Soarvo offsets all chainage calculations by that value.

Chainage Default Codes

Add these as default values on attributes of any feature type requiring chainage/offset.

Resolved when geometry changes:

!CHN — chainage along the alignment (point geometries only)
!CHNOFFSET — perpendicular offset from the alignment (point geometries only)
!CHNMIN / !CHNMAX — minimum/maximum chainage along the alignment (point or linear)

Resolved when feature is opened:

!CHNATTRIBUTE(attrName) — pull any attribute value from the alignment feature itself (e.g. !CHNATTRIBUTE(Units))