Heat Loss Map of your Borough, City or Site

An aerial infrared thermal imaging or thermographic survey can graphically illustrate the problems cities and industry face trying to cut costs and conserve energy.

Thermal imaging recordings over urban areas from an aircraft will provide measurements of heat emissions pouring into the atmosphere. Horton Levi uses military specification thermal imagers that produce high spatial and thermal resolution. Digital seamless thermal maps are then produced and geographically rectified for use in government or council GIS systems.

he thermal image below, which is one fifth of it's normal size, clearly illustrates how effective the technique is. The image is of row housing.

During a survey we record actual temperatures at ground level and provide our clients with meaningful data. The colours or temperatures can therefore be related to poorly insulated, refurbished, and empty homes for example.

The thermal image below, taken over London from 3,000 feet, clearly shows sub-surface hot water pipes that feed an estate. Had there been a leak, a warm white 'plume' would be immediately evident. This type of information can also be useful for mapping the pipe layout when records have been lost.

An energy survey is undertaken not only to save energy but to cut down on pollution. Released emissions create Carbon Dioxide gas, a major contributor to the 'Green House Effect' which is blamed for global warming and climate changes.

Apart from overseas work, Horton Levi has recently thermally mapped the whole of London and boroughs, which are now on CD. Norwich, Salford, Trafford, Sandwell and Chester-le-Street to name a few major cities in the UK have also recently been surveyed.

The above image is the Royal Free Hospital in Hampstead, London. We have thermal images of every hospital in London between Barnet and Lewisham within the M25 motorway.

The image below was captured on a heat loss survey at 3000 feet and shows heat anomalies over a land fill site.

Digital thermal maps are a mosaic of the aerial data which can be scaled exactly to an OS map as a raster layer for importation to your GIS. A thermal map will identify heat loss from homes, schools, hospitals, factories and office blocks. As a very economical option, and for non-GIS applications, street / post code and OS referenced images are provided on CD which can be displayed, magnified and printed from any simple PC software. Some authorities have opted to post this level of imagery on their websites for public viewing of their homes.

thermal imaging equipment and data processing

Fixed Wing Airborne System

Our survey aircraft is dedicated to photographic and thermal imaging work. It is fitted with stabilised sensor mounts, satellite guidance systems and a computer system linked to the infrared thermal imager / sensors. The photograph below shows our military specification imager under test mobilisation.

The photograph below shows the stabilised camera mount and computer system / digital recording equipment inside the aircraft.

Horton Levi regularly conduct surveys for government of whole cities or boroughs where precise OS grids are recorded with the necessary aid of satellite navigation and professional survey pilots.

We also conducts 'low level' surveys of single sites or small areas with a less sophisticated aircraft than the one above at very cost effective prices. 

Aerial thermal surveys of buildings to record heat loss is usually carried out mid evening at least two hours after sunset. This is considered to be the best time to allow solar dissipation and homes that are only heated during the evening to attain a comfortable heat level.

To make a "thermal map" of a large area, data collection is carried out by flying transects in a grid pattern. An altitude of between 2000 and 3000 feet  is normal to give very high resolution. This altitude is ideal for image detail and economy. The thermal imaging equipment used in all our aerial thermal surveys is of military specification. All real-time imagery is  time/date/Lat/Long encoded during the survey and hidden if required after processing.

A ground crew records absolute temperatures of roads and roofs etc at the the time of the aerial survey. This data is used to ensure that the remote temperature measurements from the aircraft are correct and adjustments can be made for emissivity differences.

Twin engine dedicated survey aircraft are always used at night over urban areas. The aircraft is fitted with satellite navigation to enable exact flight lines. Post flight "actual" flight lines are printed to scale to overlay on an O.S. map and for future G.I.S. reference.

Digital images are produced, each having an identity and O.S. map reference in grid strips or line runs. The data necessarily has to be produced into a useable file format prior to geo-rectification. The first stage process data retains all original information and being referenced to an O.S. map can be used on almost any pc with off-shelf software.

Post Processing

A large scale digital map is configured in strips of numerically referenced images. The digital data although referenced to time and flight location is not normally intended for further use once a digital computer copy has been made. The entire digital map will be contained in memory. Each image will be file referenced to an OS map and the actual flight path of the survey. At this stage, any image of any part of the map can be quickly retrieved by the file or street name and postcode reference.

Geographical sizing or scaling and overlaying on to an OS map (integration to your GIS) is a further stage in processing. The imagery will enable householders or industrial property managers to determine relative energy emissions.

The monochrome infrared image below is of an entire city. The image has been drastically reduced in size and resolution for website insertion. After a map like this has been produced, we then process the data into temperature bands. Each and every property can be clearly viewed for thermal performance. We also provide extra options for having the data correlated to post codes for individual property selection.

From the data above, thermal 'banding' of each and every building is produced. All unwanted background detail is removed. The quality of the original data and extreme care in geo-rectifying is crucial for an accurate heat mat.