Using street level imagery for a site appraisal honestly

Street imagery in a site appraisal is excellent for context and unreliable for anything you would put a dimension against. That is the whole rule, and most of the mistakes come from forgetting the second half of it. A street level view tells you the character of a road, the rhythm of frontages, the boundary treatments, the parked car density and the general condition of neighbouring buildings. It does not tell you the ridge height of the building next door, the level difference across the plot, or whether the wall on the boundary is yours.

Used with its limits stated, imagery saves a great deal of time. Used as a substitute for a visit, it produces appraisals that fall apart at the first officer question.

What imagery is useful for and what it misleads on

Useful: the street scene and its rhythm, the mix of materials at a glance, whether neighbours have already extended and roughly how, boundary types, the presence of street trees, the position of lamp columns and telecoms cabinets, the prevalence of front garden parking, and the general grain of the area.

Misleading: heights, levels, distances, roof pitches, window head heights, boundary ownership, tree species and condition, drainage, the condition of anything above ground floor, and anything obscured by a vehicle or by summer foliage.

The reasons are structural rather than a question of image quality. Street level imagery is captured from a moving vehicle at a fixed height, so the vertical perspective is wrong for judging heights. Wide angle lenses distort at the edges of frame. Stitching between frames introduces errors at exactly the junctions you want to read. And a single viewpoint cannot show a level change running away from the road.

One practical consequence. If your appraisal needs a height, get it from a survey or from an approved drawing on the council's planning register for the neighbouring property, not from imagery.

Checking the capture date before relying on it

Always. Every time. Most services display a capture date, often by month and year, and it is the first thing to read.

Three things change with vintage. Buildings get extended, so imagery from four years ago may not show the neighbour's rear extension that is now the relevant precedent. Trees are removed or planted, which matters if your scheme depends on screening or on the absence of a tree. And street layouts change, so a parking restriction or a dropped kerb may not be as shown.

Season matters as much as year. Imagery captured in July with trees in full leaf will hide elevations and boundaries that are perfectly visible in February. If the only available view is a summer one and the boundary matters, you need a visit or a winter aerial view.

Record the capture date in the appraisal against every observation drawn from imagery. It takes one line and it means nobody, including you in six months, mistakes an observation for a current fact.

Building a street scene elevation from imagery

This is legitimate as a working sketch and dangerous as a submitted drawing.

Imagery is good for establishing the pattern: how many bays, where the party lines fall, the sequence of porches and bays, roof forms, chimney positions, window proportions relative to each other. Those proportional relationships survive the perspective distortion reasonably well.

Absolute dimensions do not. To produce a street scene elevation that will withstand scrutiny you need measured information: a topographical survey covering the frontage, approved drawings for neighbouring properties from the planning register, or measurements taken on site. The usual method is to establish the real dimensions of two or three reference points and to fit the rest of the elevation to them, stating on the drawing what was measured and what was inferred.

Where the scheme is sensitive enough to need a formal visual assessment, the methodology is much more demanding and the imagery has no place in it, as our note on a Townscape and Visual Impact Assessment sets out. An annotation on the drawing saying which parts are indicative is not a weakness; it is what stops an officer treating an inferred line as a surveyed one.

Where a site visit cannot be avoided

There is a short list, and on most projects at least three items on it apply.

• Levels across the site and at the boundaries, including any retaining structure.
• Boundary ownership indicators: which side the fence posts are on, the position of walls relative to any deed plan.
• The condition of the existing building above ground floor, including the roof, the flashings and any evidence of movement.
• Trees: species, condition, canopy spread, and evidence of previous works.
• Access and visibility, since sightlines need measuring from the actual driver eye position.
• Drainage: manhole positions, covers, gullies, and which way the ground falls.
• Neighbouring window positions and uses, which drive overlooking and daylight arguments.
• Anything the imagery shows a vehicle or a skip parked in front of.

Take levels or get someone to. A scheme designed on the assumption of a level site that turns out to fall 900 millimetres front to back is a redesign, not an adjustment.

Using imagery to evidence a previous condition

This is the application where imagery is strongest, because a dated view is contemporaneous evidence of what a place looked like on a particular date.

It supports arguments about how long a use or a structure has existed, about whether a tree was present before works, about the condition of a building before a change, and about the existence of an access. For enforcement and lawful development certificate purposes, dated imagery is often the most accessible evidence available to a householder, and it is routinely put before councils and inspectors.

Two cautions. The capture date tells you the state of affairs on that date and nothing about the periods between captures, so a gap of three years leaves three years unevidenced. And imagery alone rarely establishes continuity of use, which is what the statutory time limits turn on, so it works best alongside other dated evidence such as bills, tenancy agreements or aerial photography. Our note on historic maps as former land use evidence covers the longer timeframe sources.

Present it properly: a numbered figure per image, the service used, the capture date, the viewpoint location marked on a plan, and a caption stating exactly what the image is offered as evidence of.

Copyright and reproduction in an application

Imagery is somebody's copyright work, and the terms of service of the service you used govern what you may do with it.

Three points to hold. Reproducing a screenshot in a document submitted to a council, which then publishes it on a public register, is a form of publication, and permissive terms for personal viewing do not automatically extend to it. Some services permit limited reproduction with attribution and prohibit other uses, and the terms change. And base mapping used for location and block plans is separately licensed, which is why applications are normally submitted with a plan from a licensed supplier rather than a printed screenshot.

The practical answer for most projects is straightforward. Use imagery as research, then take your own photographs for anything that goes in the submission, and use properly licensed base mapping for the plans. Where dated third party imagery is needed as evidence of a past condition, reproduce the minimum necessary with clear attribution and the capture date, and be prepared to explain why no alternative exists.

Do not crop out attribution or watermarks. It converts a defensible use into an indefensible one.

Photographing the site to fill the gaps

Your own photographs solve the copyright problem and are better evidence anyway, because you control the viewpoints.

Work to a short schedule. Photograph each elevation square on, the site from each direction of approach, the boundaries along their length, every tree, the access from the driver's eye position, any level change with a staff or a measure in frame for scale, and the neighbouring windows that face the site. Then photograph the things you will be asked about: the bin store location, the parking arrangement, the drainage covers.

Record the date and the viewpoint for each image and mark the viewpoints on a plan. Keep the original files with their metadata rather than only the versions pasted into a document, because the metadata is what gives the photograph evidential value later.

A viewpoint plan with a dozen numbered photographs is one of the most useful things you can put in a Design and Access Statement, and it costs an hour on site. It also tends to head off the objection that the applicant does not understand the context, which is otherwise difficult to answer.

This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it.

PlanScope can draft the appraisal and design documents around your own site photographs and survey information, marking clearly where a fact still needs confirming on site. For specialist technical reports, qualified professional input may be required.

PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.