CRSReproject Namespace Reference

Classes
struct	Stats

Functions
bool	reprojectModel (SWMM_Engine engine, const SpatialReferenceSystem &oldSRS, const SpatialReferenceSystem &newSRS, Stats *stats=nullptr, QString *errorOut=nullptr)
	Transform every coordinate in the model from oldSRS to newSRS.
void	transformPointsInPlace (OGRCoordinateTransformation *ct, double *xs, double *ys, int n)
	Transform n interleaved scene points in place, in chunks.

Variables
constexpr int	kTransformChunk = 65536
	Number of points pushed through OGR per batched call.

Function Documentation

reprojectModel()

bool CRSReproject::reprojectModel	(	SWMM_Engine	engine,
		const SpatialReferenceSystem &	oldSRS,
		const SpatialReferenceSystem &	newSRS,
		Stats *	stats = nullptr,
		QString *	errorOut = nullptr
	)

Transform every coordinate in the model from oldSRS to newSRS.

Uses the bulk node API for performance; loops per-link and per-subcatch for variable-length chains. Best-effort: a per-object failure logs and continues so a partially-projectable model still gets the rest done.

Parameters

engine	Open SWMM engine handle (must outlive the call).
oldSRS	Source CRS (e.g. layer's stored CRS).
newSRS	Target CRS (also written to the engine via swmm_spatial_set_crs).
stats	Optional out-param with counts of objects touched.
errorOut	Optional human-readable error if the transform itself fails.

Returns

true if the transform was built and applied to ≥ 1 object; false on hard failure (no transform, no nodes touched).

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transformPointsInPlace()

void CRSReproject::transformPointsInPlace	(	OGRCoordinateTransformation *	ct,
		double *	xs,
		double *	ys,
		int	n
	)

Transform n interleaved scene points in place, in chunks.

Replaces the Transform(1, &x, &y)-per-point pattern that made the geometry cache do ~1.5M individual PROJ calls on a 100k-node model. One call per kTransformChunk points instead.

Parameters

ct	Transform to apply. Null is a valid no-op — a layer whose CRS already matches the canvas has no transform, and every caller relied on that.
xs,ys	Parallel arrays of n coordinates, rewritten in place.

Note

Per-point failure semantics are preserved deliberately. The per-point code left an unprojectable coordinate at its INPUT value, and real models carry such points (a projection failure left ten junctions ~4e7 units out in WW-2024). Silently changing where those land — under a performance banner — would move geometry. So this passes OGR the pabSuccess array and restores the original value for any point OGR rejects, rather than keeping whatever OGR wrote.

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Variable Documentation

kTransformChunk

constexpr int CRSReproject::kTransformChunk = 65536

inlineconstexpr

Number of points pushed through OGR per batched call.

Big enough that PROJ's per-call overhead is amortised, small enough that the scratch buffers stay cache-resident and the peak allocation is bounded regardless of model size.