Commentary: Locating Relict Sinter Terrace Sites at Lake Rotomahana, New Zealand, With Ferdinand von Hochstetter's Legacy Cartography, Historic Maps, and LIDAR

This commentary addresses defects in research published in Lorrey andWoolley (2018a) and in the Frontiers of Earth Science article (Lorrey and Woolley, 2018b). This research professes to replicate the 2016-2018 reverse engineering (deconstructing survey bearings to resect the survey observation stations) of Ferdinand Hochstetter’s 1859 survey of the Pink and White Terraces in New Zealand (Bunn and Nolden, 2016); These silica sinter terraces were a national treasure. They were known as the eighth “Wonder of the World.” The Terraces attracted international tourists until 1886 when Mt Tarawera erupted, burying them. The replication presented in LW-2018a and LW-2018b draws mistaken conclusions after errata in data and in methodology. A competent survey resection is performed for this commentary, with the correct survey stations and baseline. The results are consistent with earlier reverse engineering of Hochstetter’s survey. As lead investigator, I invited Lorrey and Woolley onto the 2017-2018 PAWTL2 Project team. The objective was to obtain evidence of surviving sinter terraces, by GPR (ground penetrating radar) searches over surveyed Pink, Black, and White Terrace locations. They do not acknowledge my invitation, their project participation, access to PAWTL2 staff or my research reports; which jointly underlay their attempt to replicate our 2016-2018 reverse engineering of Hochstetter’s survey; in LW-2018a and LW2018b. Their GPR unit failed to penetrate to specified depths. Their attempted replication fails, after they experienced difficulties with interdisciplinary elements i.e., surveying, history, cartography, altimetry, and photo-interpretation (Bunn, 2019a,b). The cumulative errors in LW-2018a and LW2018b affect their resections and georeferencing, causing them to mislocate the Pink and White Terrace coordinates over today’s lake This leads LW-2018b to erroneously conclude the terraces are destroyed.


INTRODUCTION
This commentary addresses defects in research published in Lorrey and Woolley (2018a) and in the Frontiers of Earth Science article (Lorrey and Woolley, 2018b). This research professes to replicate the 2016-2018 reverse engineering (deconstructing survey bearings to resect the survey observation stations) of Ferdinand Hochstetter's 1859 survey of the Pink and White Terraces in New Zealand (Bunn and Nolden, 2016); These silica sinter terraces were a national treasure. They were known as the eighth "Wonder of the World." The Terraces attracted international tourists until 1886 when Mt Tarawera erupted, burying them. The replication presented in LW-2018a and LW-2018b draws mistaken conclusions after errata in data and in methodology. A competent survey resection is performed for this commentary, with the correct survey stations and baseline. The results are consistent with earlier reverse engineering of Hochstetter's survey. As lead investigator, I invited Lorrey and Woolley onto the 2017-2018 PAWTL2 Project team. The objective was to obtain evidence of surviving sinter terraces, by GPR (ground penetrating radar) searches over surveyed Pink, Black, and White Terrace locations. They do not acknowledge my invitation, their project participation, access to PAWTL2 staff or my research reports; which jointly underlay their attempt to replicate our 2016-2018 reverse engineering of Hochstetter's survey; in LW-2018a and LW-2018b. Their GPR unit failed to penetrate to specified depths. Their attempted replication fails, after they experienced difficulties with interdisciplinary elements i.e., surveying, history, cartography, altimetry, and photo-interpretation (Bunn, 2019a,b). The cumulative errors in LW-2018a and LW-2018b affect their resections and georeferencing, causing them to mislocate the Pink and White Terrace coordinates over today's lake This leads LW-2018b to erroneously conclude the terraces are destroyed.

ERROR IN LOCATION OF PUAI ISLAND OBSERVATION STATION
LW-2018b ignore the Puai Station western location Nolden, 2016, 2018;personal communications, Lorrey, 2017). They locate it on northeast Puai Island. Primary evidence for Puai Station is Bunn (2019a,b). This baseline error ruins their georeferencing. It nullifies their geothermal-feature coordinates in their Table S1. Analysis is then biased.
Puai Station is further mislocated by LW-2018b choosing two-bearing resection from Kumete A and C. The 14 • included angle precludes establishing Puai Station with accuracy. Multibearing resection is required from three or more surviving landmarks. Their Puai Station error is pivotal. Given the 835 m survey baseline and distal Terrace locations, each meter of Puai error increases threefold when locating the White Terrace. This is sufficient for LW-2018b to mislocate the White Terrace location over today's lake, rather than on land. LW-2018b thereby join generations of geologists in assuming the Pink and White Terraces were destroyed. The unique primary evidence of Hochstetter's survey, when properly translated, deciphered, resected, and georeferenced, does not support this conclusion.

ERRORS IN LANDMARKS AND BEARINGS
Hochstetter recorded 29 Rotomahana bearings. Eleven distal landmarks survive. LW-2018b select five bearings from four surviving landmarks: three bearings from Station 21 and two from Puai Station. Two-bearing resection is inadequate. Their selection-bias delivers Type II errors (false negatives from their stringent landmark criteria). Distal landmarks >25 km are excluded, precluding survey accuracy (which increases with distance).  found Hochstetter's bearings accurate to ≤100 km with 0.25 • mean error. Three landmarks lie on Kumete Ridge, where eruption surges passed, altering the landscape. Erosion followed, which is unmentioned. Forestry leaves Kumete Ridge periodically exposed. Here, Google Earth TM and site visits enable superior landmark identification to LIDAR.
Hochstetter provided for resecting his stations with rightangled bearing arrays from Kumete and Tarawera massif. The included angles from these arrays help confirm the landmarks (Bunn, 2019a,b). LW-2018b confine their Station 21 resection to Kumete C and D bearings, and their Puai resection to Kumete A and C. They cannot so validate their landmarks. This further invalidates their georeferencing.
Five from six LW-2018b landmark bearings are mistaken: Peak A by LW-2018b is on the plateau edge (Hochstetter recorded it as a peak on the track). This eroded position now is a forestry clearing and road (perhaps following the track). Peak A is ∼70 m NNE and ∼+10 m elevation from LW-2018b; given roadforming and erosion. This error contributes to the LW-2018b ∼600 m error in Puai Station in Figure 1.
Peak C was/is the highest point on Kumete Ridge with bearings from Station 21 and Puai. The LW-2018b assertion Peak C being co-located with Trig 543 is incorrect. There is no trig 543. Did they mean trig 3058? Trig stations did not exist here in 1859. It is unwise to assume today's landmarks were in Hochstetter's view.
Peak C location and bearing by LW-2018b from Puai is incorrect. They fail to consider Puai Station lay a meter above the lake, vs. Station 21 at +30-40 m on a hilltop. Elevationprofiling shows Kumete C (Trig 3058) and the LW-2018b location are unsighted due to the false summit. For Hochstetter to obtain the skyline, the Kumete-Puai summit bearing is taken ∼125 m in front of trig 3058, close to trig ALQC (Te Kumete). This LW-2018b error demonstrates the necessity for altimetry in such geospatial analysis. Peak D bearing by LW-2018b is incorrect. Hochstetter's bearing was 334 • 20' not 334.2 • .
Makatiti bearing by LW-2018b appears reasonable: however  noted Makatiti skyline had two high-points.
Poroporo location and bearing by LW-2018b are incorrect. Poroporo location lies buried and despite PAWTL2 research, remains unidentified. The LW-2018b proxy bearing cannot be validated without excavation and thus cannot enter the analysis. As well, LW-2018b georeferenced the location of Poroporo on the flawed Petermann map, relying on their incorrect Puai location. The actual Poroporo location georeferenced from the correct Puai Station is ∼600 m N of LW-2018b.

ERRORS IN RESECTION AND GEOREFERENCING
LW-2018b use the same Hochstetter data and International Geomagnetic Reference Field declination of +14.04 • as Bunn et al. (2018, p. 10) and Bunn (2019a,b). I tested the LW-2018b station resection using Google Earth TM in Figure 1. Their actual Station 21 proximity to our locus indicates the methodologies are consistent. This highlights LW-2018b mistakes at Puai.
Note: LW-2018a placed Station 21 on the southern shore of today's lake, with Pink Terrace ∼300 m offshore, White Terrace onshore and the old lake ∼2,500 m long. The mean LW-2018a Terrace error is ∼345 m and the lake length error ∼900 m.
Erroneous bearings confound LW-2018b georeferencing of August Petermann's map in LW-2018b Figure 12 (Hochstetter, 1864). I cannot replicate this, save by repeating their errata. When georeferencing Petermann's map over their stated (vs. actual) locations; we reproduce their smaller lake, displaced south and pivoting west (Hochstetter, 1864).
If we plot their actual locations, the Petermann map pivots ∼35 • E and extends into the eastern lake, with Terraces in midlake (Hochstetter, 1864). To reconcile, I reprised their resection using their actual Station 21 coordinates, correct Puai Station and three-bearing resection from corrected landmarks and Mt Tarawera. The result is consistent with  and Bunn (2019a,b). The White Terrace location overlaps the shore with Pink Terrace location close onshore. How LW-2018b derived their stated loci remains opaque. This is crucial when evaluating their Hochstetter replication, for it is their stated loci which they claim replicates their colleagues' locations of the Pink and White Terraces (De Ronde et al., 2018).

ERRORS IN CARTOGRAPHY
LW-2018b assert that as more diary bearings appear to agree with Petermann's map locations than on Hochstetter's map then Petermann's map is superior. This is disingenuous for they knew from PAWTL2 reports that in 2017 I established Petermann's map is defective in 12 respects; after detecting the right-angled malrotation of Lake Rotomakariri (Hochstetter, 1867;Bunn, 2019a,b).
LW-2018b displayed diary bearings over either map and reported: all station 21 internal bearings...aligned [to Petermann] with consistent precision...and within the range of compass error. This is misleading, given varying sheet orientations: Petermann's lake axis lays 10 • E against 23 • E by Hochstetter. Resection and georeferencing are required before analysis of destroyed, proximal landmarks. Bunn (2019a,b) reported the Pink and White Terrace bearings were accurate on Hochstetter but not on Petermann. Georeferencing Hochstetter's map confirms the first proximal landmark, as predicted in Keam (2016). Petermann's does not. Rangipakaru Hill persists as Patiti Island, at credible altitude (Bunn, 2019a,b). LW-2018b mislocate Rangipakaru ∼500 m W of Patiti. Hochstetter's 295 • azimuth from Rangipakaru solfatara-Patiti, tracks the Black Terrace and Black Terrace Crater transects and search boxes in Bunn (2019a,b). Other proximal landmarks may now be empirically determined by triangulation and trilateration e.g., Poroporo.
Petermann never visited New Zealand. In surveying, the field record is considered more accurate than later versions (personal communication Davies, 2018). The geothermal features were in bush and invisible. Hochstetter could take bearings via steam-plumes, with error due strong winds. This questions LW-2018b excluding surrogates, given precedent (Avery and Berlin, 1985).

ERRORS IN ALTIMETRY
Given old Lake Rotomahana vanished and the new lake, topography and elevations altered-researchers cannot establish old-lake feature coordinates without altimetry. The authors ignore the only published, evidence-based altimetry (Bunn and Nolden, 2018;Bunn, 2019a,b).   , and Bunn (2019a,b) show no such aspect-ratio distortion. On Google Earth TM the Shift key maintains aspect-ratio.

DISCUSSION
LW-2019a and LW-2018b is the first attempt to replicate our 2016-2019 Hochstetter survey research. Their replication fails due to their misplacing Puai Station, misidentifying landmarks, inadequate bearing sets, inaccurate bearings and reliance on Petermann's map (Hochstetter, 1864). The absence of altimetry restricts LW-2018b to partial, 2D analysis. These factors contribute to their incorrect lake size and georeferencing. Their stated locations for Stations 21 and Puai could not be replicated. Their mean LW-2018b Terrace error is ∼430 m. Correcting errata reveals agreement with  and Bunn (2019a,b). A competent replication of Hochstetter's survey is required, to validate Hochstetter's unique survey of this world wonder and to correct the scientific record. This will facilitate private and public sector research at Lake Rotomahana and provide closure for the Maori who grieve for relatives lost in the eruption.

AUTHOR CONTRIBUTIONS
The author confirms being the sole contributor of this work and has approved it for publication.