RICS Draft Global Guidance Note: Earth observation and aerial surveys, 6th edition

RICS Draft Guidance Note: Earth observation and aerial surveys, 6th edition

Appendix A: Sample specifications

The following four tables are basic examples of sample specifications for aerial photography, LiDAR, thermal imagery and RGB earth observation imagery. In each case, the use case for the data is stated.

Item

Aerial photography

Use case

National mapping

Accuracy

0.4m RMSE

Resolution (GSD)

0.15m

Coverage

As per supplied digital file

Project constraints

Capture imagery at low tide

Metric camera (Y/N)

Metric camera - Y

Stereo imagery overlaps

60%

Flight line overlaps

30%

Data quality AQLs

The imagery must be sharp. Flare from large expanses of glass, water or cars must be at a minimum. Colour and light should be uniform. Contrast across the block must be consistent. There should be a good match between individual flight runs and adjacent images. The photography should only be flown in conditions where the visibility does not significantly impair the image quality and detail.

Solar angle

Above 15

Deliverables

Orthophotos at 0.15m GSD

Table A1: Sample specification for aerial photography

Item

LiDAR

Use case

Railway engineering

Accuracy

0.04m RMSE

Coverage

As per supplied file

Project constraints

Urban area air traffic control

FOV

50

Data quality AQLs

The LiDAR should only be flown in good conditions, in the absence of rain, cloud, atmospheric haze, snow and flooding.

Solar angle

No restriction

Point density

48ppm2

Deliverables

Point cloud, DTM and DSM

Table A2: Sample specification for LiDAR

Item

Thermal imagery

Use case

Energy efficiency study

Accuracy

1m RMSE

Resolution (GSD)

0.5m

Coverage

As per supplied file

Start and end date

Winter period

Project constraints

Urban areas air traffic control

Equipment calibration records

Request instrument calibration records

Data quality AQLs

Has to be flown at 4C, with minimum wind of 3 m/s or slower. There should have been no rain in the previous 24 hours. The flight should take place between 19:00 and 23:00.

Solar angle

No restriction

Spectral band identification

Thermal band (3.6-4.9┬Ám)

Products/deliverables

Orthorectified thermal imagery (0.5m GSD)

Table A3: Sample specification for thermal imagery

Item

Earth observation

Use case

Land cover classification

Accuracy

<4m CE

Resolution (GSD)

0.55m

Coverage

As per supplied file

Start and end date

Summer capture

Project constraints

Capture within peak growing season

Stereo imagery overlaps

60%

Flight line overlaps

20%

Data quality AQLs

Maximum 5% cloud. Imagery to be free from dust and artefacts.

Spectral band identification

RGB imagery

Tasked imagery

Yes

Nadir angle

Better than 20

Products/deliverables

RGB orthophotos at 0.55m GSD

Table A4: Sample specification for earth observation