PhotographProposed

School Road, Acton, view 3 · Granted March 2024Photograph 22 December 2021, 10:57

Methodology

How a verified view is made, what in it is measured, and what is a judgement. Every objectively measurable property of a view can be traced back to surveyed control and recorded camera data, so it can be audited by a third party.

Explore the School Road views →Download the method statement (PDF, 9 MB) ↓

The eight stages

The same sequence on every view

Each stage produces recorded data or imagery that can be checked independently, from surveyed control through to the printed image.

PhotographyRAW capture on a full frame camera, levelled, with the lens centred over the surveyed ground mark at 1.6 m, within the 1.5 to 1.65 m eye height range in TGN 06/19.
SurveyAn independent surveyor records the camera position, height, bearing and reference points in the photograph, using RTK GNSS and total station, in OSGB36 with heights to Ordnance Datum.
3D modelBuilt from the architect's drawings and models, checked against plans, sections and elevations, and positioned in OSGB36 using a recorded false origin.
Camera matchingA virtual camera is set from the surveyed height, bearing and field of view, then aligned until the surveyed points overlay the photograph.
Independent checkA second qualified team member verifies the match. An overlay print is kept as a permanent record of match accuracy.
Lighting and renderSun position set from the recorded date, time and location, aligned to true north. Materials from the architect's specification, rendered to the agreed AVR level.
CompositionThe render is placed on the photograph with non-destructive masks where foreground buildings or trees interrupt the view. The recorded scene is not edited; lens correction and any stitching are stated in the method statement.
Output and graticuleFixed print size, with horizon line, optical axis and field of view markers on every view so its geometry can be checked.

Surveyed control

School Road, view 3

Survey accuracy

Method	Plan	Height
RTK GPS / GNSS	±10 to 15 mm	±15 to 20 mm
Total station, reflectorless	±5 mm	±5 mm
Photogrammetry / DSM	±1.5 m	±1.5 m

Tolerances accord with the RICS guidelines for the use of GPS in land surveying.

Why it matters

Distance from camera	Apparent shift per 1 m camera error
10 m	5.70°
100 m	0.57°
1,000 m	0.057°
10,000 m	0.006°

This is why near views are always survey-verified. Long-range views may be matched to 3D city models or LiDAR data, and the source is declared for every view.

Schedule of viewpoints

School Road, Appendix A.1, camera height 1.6 m

View	Lens	HFoV	Type	Date and time	Bearing	Easting	Northing	Height AOD (m)
VV01	24 mm	73.7°	AVR 0	09/12/2021 14:09	47.4°	520773.224	181894.159	33.729
VV02	24 mm	73.7°	AVR 3	09/12/2021 13:54	17.8°	520970.253	181932.375	34.974
VV03	24 mm	73.7°	AVR 3	22/12/2021 10:57	184.5°	521170.057	182238.936	30.421
VV04	24 mm	73.7°	AVR 0	22/12/2021 10:36	102.3°	521038.928	182382.716	34.244
VV05	24 mm	73.7°	AVR 3	22/12/2021 10:49	94.5°	520856.729	182177.829	37.943
VV06	24 mm	73.7°	AVR 0	09/12/2021 14:47	154.7°	520758.101	182158.354	39.801
VV07	24 mm	73.7°	AVR 0	22/12/2021 10:25	229.6°	520842.942	182552.249	36.037
VV08	50 mm	39.6°	AVR 0	10/12/2021 10:38	228.1°	520769.915	182933.607	32.974
VV09	24 mm	73.7°	AVR 0	22/12/2021 11:02	296.2°	521272.603	182347.555	29.733
VV10	50 mm	39.6°	AVR 0	10/12/2021 11:16	95.1°	521685.479	182883.586	39.613
VV11	50 mm	39.6°	AVR 0	10/12/2021 12:00	317.6°	522258.162	182238.790	30.062
VV12	24 mm	73.7°	AVR 3	22/12/2021 12:04	293.8°	522045.115	181687.619	21.165
VV13	50 mm	39.6°	AVR 0	10/12/2021 13:42	265.2°	521818.981	181287.051	13.733
VV14	50 mm	39.6°	AVR 0	09/12/2021 15:16	162.7°	519920.898	181707.541	34.432
VV15	50 mm	39.6°	AVR 0	09/12/2021 16:14	221.1°	519199.705	182299.323	46.275
VV16	24 mm	73.7°	AVR 0	10/12/2021 12:39	63.9°	521295.843	182008.789	31.921

Camera: Canon EOS 5DS R with TS-E 24 mm f/3.5L II and EF 24-105 mm f/4L. Survey: Warner Land Surveyors, GNSS baseline with robotic total station, processed in N4ce. Season: winter, leaf-off.

The photograph is evidence

From camera to plate

RAW fileCaptured with manual exposure, and kept
ConversionTo a high bit depth TIFF, with no adjustment that affects scale, geometry or visibility
Lens profileOnly the manufacturer's calibrated profile, checked against straight surveyed edges
Safe areaThe distorted outer edges of the frame are left out of the camera match

What is kept for every view

PhotographyRAW file and corrected background plate
SurveySurveyor's data for the camera and reference points
Camera matchThe match files and the archival overlay print
Sign-offStatement signed by the operator and countersigned by the independent checker

Lenses and viewing

Lenses are chosen for what the assessment needs, not for effect. The horizontal field of view is recorded for every view and used as the main check. In a built-up setting a 50 mm lens is not always appropriate, as the London View Management Framework notes; a 24 mm lens lets the viewer read the urban context. Shift lenses are used vertically only, so tall buildings are framed without converging verticals.

Printed views should be held at arm's length, or at the distance implied by the print width and field of view.

Lens	HFoV	Used for
105 mm	19.5°	Long-range relationships, distant detail
50 mm	39.6°	Standard lens, close to focused human attention
35 mm	54.4°	General purpose, moderate context
24 mm	73.7°	Urban settings, constrained spaces, tall buildings
17 mm	93.3°	Very constrained viewpoints, panoramic needs

Guidance followed

London: London View Management Framework SPG, Appendix C
Landscape Institute: TGN 06/19, Visual Representation of Development Proposals
GLVIA3: Guidelines for Landscape and Visual Impact Assessment

Modelling: Autodesk 3ds Max
Rendering: Chaos Corona
Compositing: Adobe Photoshop
Insurance: Professional indemnity insurance held, certificate on request

Explore the School Road views →Download the method statement (PDF, 9 MB) ↓