45-566: The Mount Lofty Fire Tower sits on top of Mount Lofty in the Adelaide Hills just to the east of the city of Adelaide , South Australia . The 34m high tower has a commanding view over a huge area of the rural areas surrounding Adelaide, and on a clear day the view can extend to as far as Kangaroo Island to the southwest, Monarto to the east, the Fleurieu Peninsula to the south, and the grassy plains beyond Two Wells to
90-771: A cafe-restaurant and a gift shop. Kangaroos are sometimes spotted on the trails leading up to the summit. On the ridge near the summit are three television transmission towers (the northernmost being that of the ABC ), and the Mount Lofty Fire Tower operated by the Country Fire Service . Summit Road, Mt Lofty, was historically one of the best-known addresses in South Australia, with the summer houses of several prominent families being located there. These were all destroyed or severely damaged by
135-652: A great extent that Prime Minister Ben Chifley approved the formation of the National Mapping Council of Australia in 1945 with a primary objective of planning and managing the nation's topographic mapping activities. The inaugural National Mapping Council consisted of the Director of National Mapping, the Commonwealth Surveyor General and respective State Surveyors-General. The council's first meeting held discussions between
180-538: A new Australian vertical datum. Prior to the creation of the Australian Height Datum, levelling surveys were carried out by professional surveyors for construction and mapping purposes using only local or state-based vertical datums. The execution of military operations across the Australian mainland during World War II heavily exposed the lack of Australian topographic mapping , to such
225-649: Is the highest point in the southern Mount Lofty Ranges . It is located about 15 km (9.3 mi) east of the Adelaide city centre , within the Cleland National Park in the Adelaide Hills area of South Australia . The mountain's summit has panoramic views of the city and the Adelaide plains to the west, and of the Picadilly Valley to the east. It is also popular destination for international tourists, as well as for cyclists coming up
270-537: Is the most common location for snow in South Australia; rare snowfalls sometimes occur in other parts of the Mount Lofty Ranges, and occasionally further north, in the Flinders and Gammon Ranges . Snowfall tends to be light (rarely lasting for more than a day) and does not take place every year. Sleet however is a regular occurrence. The snow is a novelty for the approximately 1.4 million residents of
315-559: The Ash Wednesday bushfires in 1983, but have subsequently been restored. They include: Other buildings, such as St Michael's House (an Anglican theological college and priory) and "Arthur's Seat", for a time known as Stawell School , a private school for girls, were never rebuilt. Part of this property was excised for the ABC-TV transmitter building and mast. Note that historically, "Mount Lofty" addresses frequently referred to
360-635: The Ash Wednesday fires in 1983. Following the Australia Live broadcast the three teenage members of the spotting crew appeared in several local media pieces and appeared in a two-page feature article in Woman's Day magazine. During February 2009 with some of the hottest weather on record, this 34m tower, the focal point for all fire-spotting activities in the Mt Lofty region, was unstaffed. CFS members say new civilian communications antennae on top of
405-556: The 1970s, the Australian Height Datum was constructed using a lower standard of spirit-levelling equipment and techniques to ensure completion in the shortest possible period of time. For example, approximately 80% (76520 km) of the primary levelling contributing to the Australian National Levelling Network was completed by private contractors during the 10-year period from 1960 to 1970. Since then, significant errors have been identified including
450-673: The 1990s, when the obelisk was repainted and restored during construction of a new kiosk. The summit can be accessed by road from the South Eastern Freeway at Crafers , and from the eastern suburbs via Greenhill Road and the Mount Lofty Scenic Route. There is a walking route up the gully from Waterfall Gully , through the Cleland National Park and from Chambers Gully . This is a 4 km uphill trek and one of Adelaide's most popular exercise circuits. The summit provides panoramic views across Adelaide,
495-568: The AUSGeoid09 model is able to “practically” eliminate the north–south error when converting GNSS readings to Australian Height Datum heights. The Australian Height Datum ( Tasmania ) is considered as a separate datum to the Australian Height Datum, consisting of a least-squares adjustment of seventy-two levelling sections across the Tasmanian state, while simultaneously assigning the mean sea level of two tidal gauges at Hobart and Burnie
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#1732779873010540-532: The Adelaide Plains (particularly for children), and photographs of it have made the front page of the local newspaper many times. Mount Lofty has a cool Mediterranean climate ( Csb ) in the Köppen climate classification , due to its elevation and very dry summers with a pronounced winter rainfall peak. The annual rainfall is nearly twice the amount, and the monthly rainfall during winter more than twice
585-547: The Australian Height Datum surface was derived and officially adopted in 1971 as the benchmark to which all new vertical height measurements in Australia are referenced to. Since the inception of the Australian Height Datum in 1971, numerous deficiencies, distortions, offsets and other errors have been identified and examined using newer technologies. Due to Australia's desperate need for a surveying vertical control and accurate topographic mapping for mining exploration during
630-479: The Australian Height Datum: the datum surface has a gradient of zero (i.e. perfectly horizontal). While this systematic error is relatively insignificant for the design of “small-scale engineering projects” that use local heights, the north–south slope is very influential on the design of “large-scale studies” that span larger distances across the country. The north–south slope is primarily due to
675-413: The Australian National Levelling Network that were used to determine the Australian Height Datum, each utilising their own levelling parties that conducted a combination of one-way and two-way levelling. These levelling parties consisted of two drivers of separate vehicles, as well as one instrument man who would alternate between the cars as they "leap-frog along the levelling route". This strategy involved
720-621: The Interior Hydro-Electric Authority One-Way Levelling Two-Way Levelling Sea level data from thirty tidal gauges positioned around the Australian mainland coastline was also collected in order to derive the Australian Height Datum. The distances between each successive tidal gauge varied significantly around the country, with the smallest interval between Port Kembla to Camp Cove (128 km) and
765-666: The National Mapping Council of Australia in July 1971. The Australian Height Datum is the vertical height of 0.000m established within the Australian National Levelling Network (ANLN), through taking the mean sea level of 30 tide gauges along the entire Australian coastline during the period of 1966–1968. The datum surface is based upon a least squares adjustment of the original, ‘primary’ levelling data spanning 97,320 km, combined with more recent, ‘supplementary’ levelling data spanning 80,000 km. Five different observing authorities contributed to primary levelling sections in
810-562: The addition of the Northern Territory and Queensland state authorities. To assist mining companies with the search for oil during the 1960s, the Federal Government made additional funds available to the Director of National Mapping to employ private contract surveyors to speed up the surveying effort. By 1970, the consolidation of levelling and tide gauge data from these collective surveying operations resulted in
855-463: The amount, of the city of Adelaide. Cloud cover is particularly heavy during the winter months. Australian Height Datum The Australian Height Datum was introduced in 1971 as the official vertical datum for Australia, and thereby serves as the benchmark to which all height measurements are referred. The Australian Height Datum is an amalgamation of decades of spirit levelling work conducted by numerous state and territory authorities across
900-487: The area now known as Crafers and to parts of Stirling . Mount Lofty is the coldest location in the Adelaide area; during winter months the temperature may not exceed 3-4 °C on some days. Adelaide's metropolitan area experiences mild winters, with temperatures virtually never cold enough to produce snow; the nearest snowfields to Adelaide are in central Victoria, over 700 km away. However, Mount Lofty's summit
945-684: The carpark below as the fire passed over them. On 1 January 1988 the Mount Lofty Fire Tower was beamed live around Australia on Channel 9 television as part of the Australia Live broadcast to celebrate the Australian Bicentenary . The three members of the spotting crew appeared on the broadcast along with former Adelaide radio journalist Murray Nicoll , who received a Walkley Award for his live report from his own street in Greenhill as it burned around him during
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#1732779873010990-480: The central reference point for surveying purposes across Adelaide. In 1902 the obelisk was rededicated and renamed as the "Flinders Column". The summit was closed to the public during the Second World War , when the obelisk was considered an indispensable navigation aid . A flashing strobe was fitted to the top to improve visibility at night. This strobe was removed after the war, but then re-installed in
1035-428: The country, and was corrected to align with the mean sea level observations of thirty tide gauges positioned around the entire coastline. While it remains the published vertical datum for all surveying and engineering operations performed throughout Australia , newer technologies have uncovered numerous deficiencies, offsets and distortions within the Australian Height Datum, leading to discussions about defining
1080-727: The entire of the Australian continent ; an activity later named the Australian Levelling Survey. From 1945 to 1955, the New South Wales , Victorian and Western Australian state authorities, with assistance from the Royal Australian Survey Corps , commenced the Australian Levelling Survey by levelling 4,800 km of the mainland. By 1960, 20,800 km of controlled levelling had been completed with
1125-399: The establishment of the two datums, the mean sea levels for the mainland and Tasmanian datums are highly likely to contain some degree of error relative to the true mean sea level value. This neglection of the differences in ocean's time-mean dynamic topography between the creation of Australian Height Datum (mainland) and Australian Height Datum (Tasmania) resulted in a distinct offset between
1170-414: The fact that the Australian Height Datum was taken as the fixed mean sea level of 30 tide gauges around Australia over a 2-year period, ignoring the natural variations in sea-surface topography . The National Mapping Council of Australia chose to use this ‘mean sea level’ approach to minimise the use of negative heights, that are quite problematic for surveyors and engineers, near coastal areas where most of
1215-518: The formation of a 97,320 km "single homogenous network" of primary levelling spanning the entire country, named the Australian National Levelling Network . Through the linear adjustment of 757 primary levelling sections across the Australian National Levelling Network, while simultaneously "holding 30 tide gauges fixed at their mean sea level values", the Australian Height Datum was determined and then adopted by
1260-427: The formation of a distinct 1.5m North-South slope within the Australian Height Datum. In order to counteract this slope, the AUSGeoid09 gravimetric quasigeoid model has been introduced to determine Australian Height Datum heights from Global Navigation Satellite System (GNSS) readings. As GPS heights provide a far greater limit of reading that the magnitude of the spirit-level errors in the Australian Height Datum,
1305-485: The height of the mainland and Tasmania datum surfaces , estimated to be between −61 mm and +48 mm. In addition to the north–south slope, numerous other regional distortions within the Australian Height Datum have been identified across the state of Western Australia. The largest of these non-linear distortions are present across the Goldfields-Esperance and northern Kimberley regions. Unlike
1350-411: The instrument man taking both a back sight and fore sight staff reading, before being driven by one of the drivers, past the other driver's stationary car, to the next set-up position to take the next set of reading. The two drivers’ responsibility was to hold the levelling staffs , while the instrument man would operate the level and record the readings in a level book. By employing this strategy,
1395-473: The largest interval between Point Lonsdale to Port Kembla (1,150 km). Sea level observations were conducted on an hourly basis from 1 January 1966 to 31 December 1968 for 29 of the designated tidal gauges, and from 1 January 1957 to 31 December 1960 for the single tidal gauge at Karumba , Queensland . Once all the tidal data was collected and processed, the Port MacDonnell tidal gauge station
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1440-458: The levelling parties were able to achieve an average of 35 km of primary levelling each day. One-way levelling involved adopting this outlined methodology in only one direction, while two-way levelling also would repeat this again in the opposite direction to improve the accuracy of the readings. The following outlines the cumulative contribution of the levelling parties for their respective observing authority: (Combined) National Mapping
1485-536: The mid-1990s a volunteer unit was established specifically to operate the fire tower, and this was then formally recognised as a Country Fire Service brigade in November 2000. The National Parks and Wildlife Service crew who staff the tower during the Ash Wednesday fires on 16 February 1983 later recalled the ferocity with which the fire came tearing up through Cleland Conservation Park towards them. The main fire that day started at nearby Mount Osmond and reached
1530-466: The nearby town of Uraidla . Mount Lofty was named by Matthew Flinders on 23 March 1802 during his circumnavigation of the Australian continent . The explorer Collet Barker was the first European to climb it, in April 1831, almost six years before Adelaide was settled. A stone cairn at the summit was originally used to mark the trig point , and in 1885 this was replaced by an obelisk which served as
1575-455: The north. The tower is used to spot fires in the Adelaide Hills and surrounds on days of very high or extreme fire danger during summer. The spotting crew determine the location of a smoke sighting by taking a bearing and then calculating distance using topographic maps. Details of the sighting are then passed to the 'Adelaide Fire' Communications Centre who despatch the nearest fire brigade. The tower, which sits within Cleland National Park ,
1620-469: The north–south slope of 1.5m, offset between Australia mainland and Tasmania of 26 cm, as well as regional distortions throughout Western Australia. The North-South Slope is a systematic error in the Australian Height Datum's horizontal surface of approximately 1.5m from the North coast to South coast of Australia. This tilt is quite problematic, as it invalidates the major assumption in using
1665-522: The old Mount Barker Road through Eagle on the Hill , and for walkers from Waterfall Gully . The adjacent peaks of Mount Lofty and Mount Bonython form a prominent landmark visible across the Adelaide Plains , known to the local Kaurna people as Yuridla , 'two-ears', part of the body of an ancestral being called Nganu. This Kaurna name has been preserved in its anglicised form as the name of
1710-431: The population resides. By utilising the mean sea level approach, the creation of the Australian Height Datum neglected the significant influence the ocean's time- mean dynamic topography on the fluctuations in sea surface levels around the country. Spatial variation of sea level change , freshwater outflow in harbour areas where tide gauges are positioned, and an amalgamation of ocean dynamics have all contributed to
1755-415: The respective state authorities about the need to have a unified national scheme for surveying and mapping of Australia. Upon the meeting's completion, members of the National Mapping Council of Australia unanimously agreed that the Director of National Mapping, Frederick Johnston , would be tasked with the coordination of local, state and Commonwealth authorities in order to execute mapping activities across
1800-452: The summit of Mount Lofty well within an hour (a typical bushfire would take several hours to cover this same distance). Visibility was obscured due to severe dust storms generated by the strong winds, and the crew only evacuated the tower as the fire was literally at their doorstep. Although the steel structure of the tower survived intact, the windows of the 34m high tower were completely shattered. The spotters were forced to simply shelter in
1845-731: The tower made it sway uncontrollably in wind. Two experienced fire spotters feared for their own safety before they walked down the spiral staircase to the ground. The tower was re-opened after a years absence, and has been regularly staffed each fire season since by the Mount Lofty fire tower brigade of the CFS. 34°58′28″S 138°42′32″E / 34.97444°S 138.70889°E / -34.97444; 138.70889 Mount Lofty Mount Lofty ( 34°58′S 138°42′E / 34.967°S 138.700°E / -34.967; 138.700 , elevation 710 m (2,330 ft) AHD )
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1890-405: The vertical height of 0.000m over the year of 1972. This method deviates from the method employed to determine the mean sea level used to create the mainland Australian Height Datum, which was taken across the period from 1966 – 1968 for 29 of the tidal gauges and 1957-1960 for the single tidal gauge at Karumba . By employing inconsistent approaches to the study period of the mean sea level during
1935-474: The well-defined and measurable north–south tilt across the state, the linear regression of these distortions does not lend itself to any distinct trends. Moreover, the utilising gravimetric quasigeoid models to “practically” eliminate the impact of the ocean's time-mean dynamic topography does not minimise the extent of these regional distortions. For these reasons, the regional distortions throughout Western Australia are attributed to random errors “present in
1980-414: Was built in 1980 and initially staffed by National Parks and Wildlife Service officers. The Country Fire Service took over responsibility for the tower in 1987, recruiting a paid staff of three fire spotters on a contract basis who between them maintained an eight-hour watch for the entire Fire Danger Season from 1 December to 30 April. The spotting crew typically reported close to 200 sightings per season. In
2025-467: Was selected to be the “nominal origin” and the station's mean sea level was assigned a value of 0.000 m. Zero condition equations between Port MacDonnell and the other 29 stations’ sea level data were then utilised to hold the mean sea level at 0.000 m across the entire national tide gauge network, while the primary and secondary levelling records within the Australian National Levelling Network were simultaneously adjusted to fit this model. In doing so,
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