OS HQ Maybush | Photogrammetric Services 2
- This page:Photogrammetry & Remote Sensing developments & production 1986-89.
- Status : Completed [sub pages to be added in a future release]
- First published: 10 March 2019
Zeiss P3 Tests - Settings - March 1988
Photo credit: N/A
This article covers the period from autumn 1986 to the end of 1989.
The Air Survey Review had resulted in a major overhaul of the unit.
OS and National Context:
A summary of the operating environment for this period:
Photogrammetic Services 2 Role, Operations and People:
Ordnance Survey , Romsey Road Maybush, Southampton, SO9 4DH
This was Ordnance Survey Headquarters
Photogrammetic Services was housed on the ground floor of North Block [now named Compass House]Building still exists: Yes
Activities of Photogrammeric Services:
- 1:10000 Contouring [PS1
- 1:1250 Photogram Update [PS1]
- 1:2500 Photogram Update [PS1]
- 1:10000 Photogram Update [PS1]
- Aerial Photography Acquistion [PS1]
- Aerial Triangulaton [PS1]
- Air Photo Rectification [PS1]
- 1:1250 Photogram. Resurvey [PS2]
- 1:2500 Photogram. Resurvey [PS2]
- 1:1250 Photogram. Reformed Mapping [PS2]
[PS1 - PS2 ] indicates the main division of tasks [some overlap depending on whether existing mapping was digital]
Photogrammetic Services 1 & 2 was managed by a senior manager John Farrow with two middle managers ~40 staff. Dave Hockaday held the role of Technical Assistant to Photogrammetric Services.
Around late 1988 Photogrammetry was merged with Survey Computations and renamed PSC. Dave Murphy replaced John Farrow who had moved to Research & Development.
The staff of Photogrammetry
This photo includes a sub set of photogrammetry staff in the courtyard of what is now Compass House.
It includes: Peter Wesley [Head of Topo Surveys], Dave Murphy [Manager P&SC], Nick Papps [BM PS2] and Dave Costard [System Manager]
Photo credit: probably OS?
PS1 & PS 2 Equipment
The equipment below reflects the situation in late 1986 - much would change.
PS1 was responsible for the planning and acquisition of photography, aerial triangulation and non-digital map production. PS2 covered digital map production and had a small development team.[
Analogue Plotting Instruments
Photogrammetic Services continued to be supported by the same equipment as listed in the 1980-82 article during this period. This was high capital cost equipment and remained serviceable.
Analytical Plotting Instruments
The modernisation of photogrammetry led to several analogue plotters being fitted with encoders and were now able to capture digital data. The data was captured into a data fuile held on a dedicated PDP-11 computer. It was transferred via disk to an edit station and the data was cleaned up.
A Kern DSR-11 analytical plotter had been purchased in addition to the DSR-1, second DSR-11 would be added during this period.
The DSR-1 was dedicated to aerial triangulation - the size of the first hard disc for this system was just 10Mb].
PS2 had two high resolution graphics screens, a Tektronix model and and a much less expensive Ramtek (which emulated the Tektronix).
While all the plotting instruments (except the DSR-1) had plotting tables PS required a table to create Master Survey Documents(to send to the field for completion) and a Kern GP-1 had been purchased for this.
1989 - Survey Aircraft
Over the Yorkshire Dales:
At the end of the 1989 photography season we paid a Sunday visit to the aircraft at Blackpool.
We took a short flight over Blackpool and over the Trough of Bowland to Settle round and back to Blackpool. it was quite instructive in terms of operation (we did not take any aerial photos). We were flying just below cloud level and it was a little bumpy - I discovered that the rear of the plane is not the best location in those circumstances.
View from the camera operators chair at the rear - to Dave Murphy (right) and Mike Proctor (left). The aerial camera is in the foreground.
Unfortunately we got delayed in Blackpool and M6 traffic on the return trip and had to stay overnight in Birmingham - all three of us in the same room - a secret until now.
Photo credit: KM
The cameras were being replaced as new technology was becoming available. A Wild RC10A camera was purchased. Later a Zeiss [?] camera with Forward Motion Compensation] would be purchased. GPS and Inertial systems would also be introduced.
Main activities of Air Survey Branch at this time:
The main activites os PS at this time were:.
- completion of the 1:10,000 metric contouring programme
- 1:1250 town upgrades [shared with the private sector]
- 1:2500 reformed mapping programme
- map updates [all scales]
Reformed Mapping Programme
The reformed mapping programme recognised that the 1:2500 Overhaul work had left weak areas in terms of positional accuracy. The original aim of the programme was to capture a skeleton of topographic features and use that to transform the remainder of the existing digital map. This rarely worked since the positional errors were not systematic. This meant capturing more new data and it got to a point where the edit of the new and old took more time than addional capture. Hence it tended towards a resurvey.
Resurvey of minor towns
There were around 20 towns being upgraded to 1:1250 in any one year and additional capacity for this came from the private sector. An example of this includes the Elgin upgrade which employed a half frame camera mounted on a helicopter [see Photogrammetry MSc dissertation - to be added ]
Digital Map Update
For the future efficient digital map update was vital but this was also a major challenge. Just as the surveyor had overlaid a hardcopy map on top of an aerial photograph we had to find a similar solution. It was called 'stereo superimposition' where the digital map is injected into the optics of the plotter viewing the photography.
In 1988 I tested two instruments fitted with superimpostion [Zeiss P3 (Germany)& Intergraph IMA (Swindon)]. Kern also manufactured a system [KRISS] that could be retro-fitted to the DSR-11. In 1989, after the merger with Survey Computations, we established a trial to determine how we miht best move forward [see Digital Map Update Trials - to be added ]
During the winter the Photogrammetric Society ran a series of evening lectures in Burlington House, Piccadilly. An OS minibus would take staff to these events which proved both valuable in terms of content and networking with people from the private, public and commercial sectors. The RICS also ran a simialr programme.
Following the MSc in Photogrammetry this work was a logical next step. The work commenced with the new but not very efficient technical infrastructure for PS2 a- this is described in the article below. We switched from the Kern supplied editing software to Laser-Scan's LITES2 and the entire flowline was redesigned and streamlined.
During this period I undertook my first overseas trips eg to the Zeiss factory in Oberkochen and the OEEPE LIS/GIS Seminars at EPFL in Lausanne. Stereo superimposition was a breakthrough allowing an operator to view the digital map overlaid on the stereo imagery - providing an ideal environment to map change and update the data.
Two overseas mapping projects were also undertaken - these were both ground breaking using imagery from the new French SPOT satellite.
We had some significant successes in PS and I am grateful to both John Farrow and Dave Murphy - different characters but very supportive and progressive individuals - this was a rewarding period.
Last Updated: 19 April 2018