Showing posts with label Surveys: Fforest Glud. Show all posts
Showing posts with label Surveys: Fforest Glud. Show all posts

Monday, 18 October 2021

Mapping Mountains – Trimble Surveys – Fforest Glud

 

28.08.21  Glascwm (SO 169 525) and Black Hill (SO 174 523) 

Glascwm (SO 169 525)

Glascwm and Black Hill were the last two hills in this area remaining to be surveyed or to be analysed via LIDAR.  Sometimes that need to create accurate numerical data can take you to beautiful quiet places and today these hills fulfilled all objectives and needs. 

After meeting Aled in Caersŵs at 8.00am, we were soon parked above the small community of Rhulen.  I dropped Aled off as he planned a traverse heading north-east over Red Hill, an Uchaf to the east of Cefn Wylfre, before meeting me on Glascwm or Black Hill.  I waved him off and then drove on the narrow lanes through the small community of Glascwm and up to the top of the road pass to the east. 

From the high road, with land nearby also constituting the bwlch of Glascwm, I followed a track heading upward initially beside a fence and then over open hillside.  A number of sheep gazed my way as the first signs of brightness broke through the morning cloud.  Buzzards circled overhead with an occasional Red Kite majestically gliding across the sky.  It was good to be out on the hill. 

Gwaun Ceste (SO 158 555) from the ascent of Glascwm

As I gained height I stopped and looked at the two 1:25,000 maps that cover these hills and estimated how long it would take Aled to get to the summit of Glascwm.  He is younger and much quicker than me, and would probably make it to this summit around the time that I was on its top or just below at the bwlch connecting it with Black Hill, both of which would be surveyed. 

The track bisected with one branch heading southward, whilst I followed the one heading up.  This soon brought me to within a couple of hundred metres of the summit of Glascwm.  I had a good look for the few stones supposedly marking the summit, but could not find them.  If these still exist they are now immersed in the heather.  I soon had the Trimble set up gathering summit data. 

Gathering data at the summit of Glascwm

During data collection I peered southward but could not see Aled, although he later told me he could see me on the summit.  It was a delight to be here in the morning sunshine, with a welcoming slight breeze wafting across the hill.  On days such as this the Radnorshire hills are welcoming places, and as the Trimble quietly beeped away collecting individual datum points I soaked in the scene of peaceful solitude. 

Before leaving the summit I had one last look toward the south for Aled, but still couldn’t see him, so I turned and headed back to the continuation of the track, following it down toward the bwlch separating Glascwm from Black Hill.  I’d been this way before, many years ago, I remember on that day, although the hills were clear of cloud, that it was grey, which added to the feeling of wilderness.  Today with blue skies overhead these hills gave a very different feeling, where to linger was to enjoy their openness. 

Black Hill (SO 174 523)

Once at the bwlch I assessed the lay of land from a number of directions, before placing the Trimble where I judged its critical point to be positioned.  As the equipment gathered data I stood back and soaked in the scene, taking a few photographs of the purpled heather and big blue skies. 

Gathering data at the bwlch of Black Hill

As the equipment neared its five minutes of allotted data collection I walked back to it, pressed ‘Done’ and closed it down and packed it away.  As I turned to make my way up Black Hill I looked up toward Glascwm and there was Aled waving back at me.  He’d made good progress. 

Aled heading down from the summit of Glascwm

Once he joined me we stayed at the bwlch for a few minutes before heading up Black Hill.  The summit of this hill is similar to that of Glascwm; and mainly consists of soft heather.  As the Trimble gathered data we sat below the summit looking out to the east, any distant view was hazy, but the view was still to be savoured. 

Gathering data at the summit of Black Hill

All that remained was to close the Trimble down, pack it away and head back on the track, reclaiming lost height over Glascwm and down to my awaiting car.  Once back at the car we quickly assessed the lay of land for the bwlch position adjoined to Glascwm. 

Gathering data at the bwlch of Glascwm

Having chosen the spot for Trimble placement, I approached this position and as I did so Aled pointed toward a number of wooden boxes close to where I was heading; these were bee hives!  The bees hummed around the bwlch, a constant sound.  I quickly set the Trimble up, and walked back a safe distance, waited for the 0.1m accuracy level to be attained before data should be logged, and once attained I set it to gather data and marched back away from the hives.  Once sufficient bwlch data were gathered and stored I quickly approached the Trimble, closed it down, took a couple of photographs and headed back out of the field and away from the bees. 

 

Survey Result: 

 

Glascwm

Summit Height:  523.5m (converted to OSGM15)

Summit Grid Reference:  SO 16976 52509

Bwlch Height:  392.6m (converted to OSGM15)

Bwlch Grid Reference:  SO 16656 53409

Drop:  130.9m

Dominance:  25.00%


 

 

Black Hill

Summit Height:  518.0m (converted to OSGM15)

Summit Grid Reference:  SO 17412 52321

Bwlch Height:  493.6m (converted to OSGM15)

Bwlch Grid Reference:  SO 17272 52536

Drop:  24.4m

Dominance:  4.72%


 

For further details please consult the Trimble Survey Spreadsheet

 

 

 

 

Monday, 9 August 2021

Mapping Mountains – Trimble Surveys – Fforest Glud


12.060.21  Colfa Hill (SO 194 553, previously Trimbled), Cefn Hir (SO 205 550), Caety Traylow (SO 197 561) and Cnwch Bank (SO 186 554) 

Cefn Hir (SO 205 550)

With the weather set fine, albeit warming up in the afternoon, I headed back to the Radnorshire hills in the company of Aled.  Today we wanted to visit the hills around and including Colfa Hill.  This small grouping of hills form a block of high land between the main Fforest Glud massif to the north and Gwaun Ceste and Glascwm to the west and south-west respectively. 

We had a number of surveying objectives that unusually didn’t include the highest hill; Colfa Hill, which had been surveyed with the Leica GS15 and Trimble GeoXH 6000 in October 2015, this was also the last survey that John, Graham and I did together. 

Having asked permission to park on a small strip of tarmac adjacent to the narrow lane and a house close to Colfa Farm, we were walking by 9.10am following a track up to a path through the periphery of a near wood and then out on to fields and eventually the open hill. 

Ahead lay the continuation of the track heading off in to the distance with infant fern sprouting their new and fresh greens and darkened heather all intimating that in these parts if a path or track is found it is best to follow it.  As height was gained the view soon opened up and in the distance the distinctive profile of the Malvern Hills was easily picked out. 

Always a welcome sight to see when on the hill

We soon stopped to watch three moorland ponies who nonchalantly looked our way, two white and one brown; they stood close to a sea of fern on a small patch of cropped grass with the near hillside descending to the valley below and distant hills forming a backdrop.  It was a lovely scene to behold early in the morning, where except for a welcoming cooling breeze and the ever present song of the Skylark nothing seemingly stirred. 

One of the moorland ponies on our way to Colfa Hill

Leaving the ponies we continued on the track toward a small pool.  We had a number of options how to visit the hills on our circuit with Colfa Hill; our high point of the day, either being the first or third hill to visit.  From beside the small pool the triangulation pillar on top of Colfa Hill looked ever so close and as the track headed up toward it we decided to visit this hill first. 

The small pool on the way to Colfa Hill

I hadn’t visited Colfa Hill since surveying it with John and Graham in October 2015, prior to this I had visited the hill on three occasions and therefore this was my fifth visit.  A surprising total when I checked my tick-lists.  As the summit had already been surveyed with the Leica and Trimble I did not gather further data and stood enjoying the view after taking a few photos of Aled beside the trig pillar. 

Aled at the summit of Colfa Hill

Leaving the summit of Colfa Hill we soon found an overgrown track heading in the direction of our next hill; Cefn Hir, which lay ahead of us as a patchwork of browns and greens with patches of cut heather giving a hope of relatively easy underfoot conditions leading to its summit. 

Heading toward Cefn Hir

The track wound its way around the upper part of a steep sided dingle that glowed back as sunlight and shade worked magical tricks upon the land.  From here we set off over patches of heather toward the connecting bwlch which was the first point to survey.  Two positions were surveyed for the critical point, both on the valley to valley traverse. 

Nearing the bwlch of Cefn Hir with Mynyddoedd Duon in the background

After packing the equipment away we re-joined the track and were soon standing on the summit of Cefn Hir.  We spent a few minutes assessing the lay of land for the high point and having decided the summit lay close to the edge of a patch of cropped heather the Trimble was soon set up gathering its allotted data.  During data collection Aled sat looking out to the wilds of deepest, darkest England which spread out before him, whilst I stood scribbling all necessary detail in my surveying notebook. 

The Trimble set-up position at the summit of Cefn Hir

When the sun is out and a cooling breeze skims across the tops, the Radnorshire hills are always a delight to visit.  They are quiet places, with few hill walkers, but they give a tranquil habitat where peace of mind is easily found with contentment of place and view that much other upland in Wales cannot match. 

Looking beyond the Mawn Pools to our route from Cefn Hir

Our route now headed north-westward toward the summit of Caety Traylow with another more than welcome track leading us toward its high point.  This track stretched out across the moor, a beacon not to waver from.  We stopped beside the Mawn Pools which nowadays is mainly a flat bedded land of cotton grass and no doubt bog, but a pool still exists, although probably much smaller than in years gone by.  Following the land of the Mawn Pools west would lead to the bwlch of Caety Traylow, but first its summit was to be visited and surveyed. 

LIDAR summit image of Caety Traylow

We left the track to head off over small patches of heather and bilberry to the summit of Caety Traylow, this was the only point on the day’s walk that was covered by LIDAR.  Having arrived at the summit and assessing the lay of land we were of the opinion that slightly higher ground was to be found about three metres from where LIDAR gives the position of the summit, and this is where the Trimble was set up.  During data collection I sat with Aled and ate an egg sandwich; a much needed bit of replenishment as the heat was slowly but surely taking its toll. 

Gathering data at the summit of Caety Traylow

The next point on the day’s surveying agenda was the bwlch of Caety Traylow which looked as if it was placed in a bog.  This is the continuation of the land heading up from the Mawn Pools which we had passed on our way to the hill’s summit.  On our way to the bwlch a lone walker was spotted heading up a track between the summits of Caety Traylow and Colfa Hill.  As we approached the area of the bwlch the same walker was heading back down, and except for this sighting we just had Skylarks as company, these little birds gave a background of ever present song; a joy to here at this time of year. 

I used the ten figure grid reference from the spot height that appeared on the Ordnance Survey Vector Map Local that was hosted on the Geograph website to zero in to the position of the bwlch.  However, land hereabouts comprised heather, reed grass, tussocks, a number of small grassed channels and small stagnant pools, therefore its critical position may be best decided upon when LIDAR is available for this area.  As the Trimble quietly beeped away gathering data I sat on a tussock savouring the position I was now in, if not for this esoteric pastime of surveying hills I would never have visited this place.  Probably for good reason, as I suspect during much of the year this bwlch is a quagmire of bog, thankfully today it was relatively dry and a delight to visit. 

Gathering data at the bwlch of Caety Traylow

Just one hill remained to survey; Cnwch Bank, which forms the descending westerly ridge of Colfa Hill.  Using this ridge as our descent gave an alternate route down as otherwise we would have doubled back on our inward route.  It also gave an opportunity to add accurate heights for this low prominence hill for both its summit and bwlch. 

We took two data sets from the bwch of Cnwch Bank on the hill to hill traverse and a further two data sets for its high point, with the first of the latter sets our preferred position for this hill’s summit.  As the Trimble gathered the last of these data sets I knew the heat had battered me.  Unfortunately my body does not react well to heat, it never has, however enjoyable a warm summer day can be and especially so when on the hill.  Over many years I have accustomed myself to be wary of undue exercise when summer temperatures increase, therefore nowadays I try and pick routes with less mileage than perhaps a few years ago; just enough to enjoy, but not too much to hinder. 

Gathering data at the summit of Cnwch Bank

As we left Cnwch Bank, we also left behind the welcome breeze and although the descent down the hill’s southerly ridge was on a beautiful green track, the lack of breeze meant that for me it was like descending in to a hot cauldron.  I felt battered and this was to continue for the next hour or so. 

The route down was beautiful; it was like descending in to summer.  Stilled mature trees canopied the land with yellowed buttercups swarming across near fields.  The only vestiges of cloud were high in the sky and delicate wisps leaving a deep blue colour dominating.  The scene was to be savoured, but it was also warm and I suffered, so much so that our plan to visit Glascwm and Black Hill later in the afternoon was shelved.  I think if I had attempted these two hills I may have ended up in serious trouble. 

Colfa Hill with conditions beginning to get uncomfortably warm

The track led down to Middle Fynnonau where we stopped and chatted to a woman, it was a welcome rest.  Beyond, the track headed through a ford with a footbridge near at hand.  The sun continued to beat down. 

The ford beyond Middle Fynnolau

Eventually the rough track merged with a narrow paved lane, this led back on to the lane where the car was parked.  Between us and it was a slight uphill, by now I was wilting under the heat and just wanted to stop and bury my head in a bucket of water. 

The Church of St David's at Colfa

The much needed rest came with the peaceful surrounds of St David’s Church.  I sat inside this building recovering a semblance of decorum and turned my brow beaten mind away from the increasing temperatures outside and just sat and slowly recovered.  Remnants of painted frescoes adorned the walls with an old skull and crossbones standing out; a sign of the inevitability of death and the hope of resurrection. 

The skull and crossbones in Colfa Church

Leaving the Church it was only a short distance to Colfa Farm where we met Jane Lloyd.  We stopped and talked with Jane for a number of minutes.  She had lived at this farm all her life with her parents moving here from Herefordshire.  She led us across the hills and named all the ones we had visited earlier in the day.  She seemed quite impressed with our route; I was tempted to say ‘so was I’. 

It was a pleasure meeting Jane and she kindly posed for a few photos just before we set off toward the awaiting car.  I so enjoy meeting people from the farming community, many have a great wealth of knowledge for the hill or mountain that they work.  This knowledge is to be savoured and also saved as it forms a part of our rich heritage and culture and spans the time between historic and present times. 

Jane Lloyd of Colfa Farm

Arriving at the car was a delight, it took an inordinate amount of time for me to change in to dry and clean clothes.  I was in no rush, I munched on an apple that Aled offered me, waved at farm vehicles as they passed on the narrow lane, luxuriated in getting my walking boots off and then feeling the warmth of the sun on my body that up until now had wilted under its heat. 

The day was rounded off with a good meal in the beer garden in the Severn Arms in Pen-y-bont, the pub where Linda and I had also eaten on my last walk a week or so ago. 

 

Survey Result: 

 

Colfa Hill

Summit Height:  532.2m (converted to OSGM15, from previous Trimble GeoXH 6000 survey)  532.2m (converted to OSGM15, from previous Leica GS15 survey)

Summit Grid Reference:  SO 19449 55397 (from previous Trimble GeoXH 6000 and Leica GS15 surveys)

Bwlch Height:  387.8m (converted to OSGM15, from previous Trimble GeoXH 6000 survey)  387.7m (converted to OSGM15, from previous Leica GS15 survey)

Bwlch Grid Reference:  SO 17968 55359 (from previous Trimble GeoXH 6000 and Leica GS15 surveys)

Drop:  144.4m (from previous Trimble GeoXH 6000 survey)  144.6m (from previous Leica GS15 survey)

Dominance:  27.16% (from previous Leica GS15 survey)


 

 

Cefn Hir

Summit Height:  510.5m (converted to OSGM15)

Summit Grid Reference:  SO 20521 55051

Bwlch Height:  495.1m (converted to OSGM15)

Bwlch Grid Reference:  SO 20261 55163

Drop:  15.4m

Dominance:  3.01%


 

 

Caety Traylow

Summit Height:  522.3m (converted to OSGM15)

Summit Grid Reference:  SO 19789 56130

Bwlch Height:  501.2m (converted to OSGM15)

Bwlch Grid Reference:  SO 19299 55578

Drop:  21.1m

Dominance:  4.05%


 

 

Cnwch Bank

Summit Height:  508.8m (converted to OSGM15)

Summit Grid Reference:  SO 18692 55406

Bwlch Height:  500.6m (converted to OSGM15)

Bwlch Grid Reference:  SO 18806 55498

Drop:  8.2m

Dominance:  1.62%


 

 

For details on the survey of Colfa Hill

 

For further details please consult the Trimble Survey Spreadsheet 

Sunday, 1 August 2021

Mapping Mountains – Trimble Surveys – Fforest Glud


01.06.21  Trefaesyfed (SO 211 609)

LIDAR image of Trefaesyfed (SO 211 609)

Having visited and surveyed Nyth Grug (SO 170 606) and Mynd (SO 181 592) with the added diversion to the base of the Water-breaks-its-neck waterfall, I drove the short distance to Maesyfed (New Radnor), parked in the centre of the slumbering little village and asked a man who was out tending the front of his house the best way to the old castle.  He gave directions and soon Linda was heading up the near path leading toward the church with me contentedly following behind. 

The church in New Radnor

We followed a secondary path beside grave stones up toward where we hoped to gain access to the castle grounds.  However, our route just led to a wired fence, turning around we descended the short distance back to the main path and continued toward the church. 

Follow the path to the kissing gate and the old castle is beyond

Before heading up to the old castle we visited the church and sat in its cooling realm, it was peaceful except for the calling of a bird which squawked loudly from outside.  The person who gave us directions told us to follow the path beyond the church to a kissing gate and as we walked around the front of the church there it was; up ahead. 

Trefaesyfed - the old castle in New Rdanor

Beyond the kissing gate long grass and flowers meandered in the breeze, all ground led steeply up to an extensive area where once the castle was situated, with the remains now incorporating an impressive Norman motte.  As we crested the upper part of the steep ground two people came in to view.  Each sitting beside the other on the escarpment edge, reading books in the sunshine, it was similar to a scene from the Hay Literary Festival. 

Gathering data at the summit of Trefaesyfed

Prior to our visit I had analysed this hill via LIDAR, but even without the aid of LIDAR the high point of the castle’s remains would have been easy to pinpoint and now standing on its top I checked the co-ordinates produced by LIDAR and to within a metre they matched what the Trimble was showing. 

C'mon Phillips, I've had enough of these hills, I'm off to the pub

As the Trimble gathered data I sat with Linda just a few metres from the equipment on the steep summit bank, listening to the beeps as it gathered its individual datum points.  Once the allotted data were gathered and stored, I closed the equipment down, took a few photographs and we headed steeply down past the church to the awaiting car.  The day was rounded off with a good meal sitting in the sun in the beer garden at the back of the Severn Arms pub in Pen-y-bont, this proved a good ending to an excellent day. 

 

Survey Result: 

 

Trefaesyfed

Summit Height:  274.4m (converted to OSGM15, Trimble GeoXH 6000 survey) 

Summit Grid Reference:  SO 21157 60984 (Trimble GeoXH 6000 survey) 

Bwlch Height:  267.2m (LIDAR)

Bwlch Grid Reference:  SO 21030 61031 (LIDAR)

Drop:  7.3m (Trimble GeoXH 6000 summit and LIDAR bwlch)

Dominance:  2.64% (Trimble GeoXH 6000 summit and LIDAR bwlch)

 

 

For further details please consult the Trimble Survey Spreadsheet

 

 

 

  

Friday, 30 July 2021

Mapping Mountains – Trimble Surveys – Fforest Glud

 

01.06.21  Nyth Grug (SO 170 606) and Mynd (SO 181 592) 

Nyth Grug (SO 170 606)

These two hills are positioned to the south of Great Rhos and if so desired can be combined with their higher neighbour.  However, as the summit of Great Rhos was Trimbled five days ago it was just Nyth Grug and Mynd that were on the day’s surveying agenda, and as our planned route took us over the bwlch of Crin Fynydd I hoped to also gather data from this point if the near conifers permitted. 

I was out with Linda today, my old lockdown, keep local walking buddy.  My memories of walking with Linda consisted of ear warmers, balaclavas, wellies and full winter gear visiting the delights of Yr Allt and Y Golfa and its adjacent hills.  Today was an utter contrast to those winter walks as summer had arrived giving warm temperatures on the hills. 

We were walking on the forested path beside the Water-breaks-its-neck waterfall by 9.00am, following dappled light up beneath the canopy of blues and greens.  The path led over a footbridge at the top of the waterfall and then continued downward, we left it at this point and joined a narrower path that led to a public footpath close to Warren House. 

Heading up the path leading to the top of Water-breaks-its-neck

Conditions were warm on this section of the walk and especially so as we headed beside the near conifer plantation up a field where two horses stood in the morning sunshine; one on our path bolt still, the other inquisitively roaming over to investigate the two new arrivals.  Beyond the field we entered forestry. 

Linda emerges out of the wood with Mynd in the background

The path through the forest was a delight and gave shade to the morning’s proceedings.  We stopped at the bwlch of Crin Fynydd, with its summit immersed in conifers just to our south.  It was pointless trying to gather Trimble data from its summit, but I hoped bwlch data could be gathered. 

On the path leading to the bwlch of Crin Fynydd

Whilst I assessed the lay of land Linda chose a spot and bedded down in the sun, she’d worked a 17 hour shift two days ago and deserved a good rest whilst on the hill.  We spent about 30 minutes at this bwlch, I positioned the Trimble facing in three different directions, but every time the 0.1m accuracy level before data should be logged was not attained, and therefore I eventually closed it down without any data having been collected. 

A well earned rest after a 17-hour shift

The bwlch of Crin Fynydd

Our route continued, now on the periphery of the forestry following a good track up valley with the stream feeding the waterfall down on our left.  We left the main track and followed a narrower path that exited the last of the conifers and gained open hillside.  From here to the bwlch of Nyth Grug was beautiful with open hill, few fences, blue sky, roaming sheep, circling Red Kites, a cooling breeze and not another person in sight. 

At the bwlch Linda again lay in the sun without a seeming care in the world.  The critical point of the bwlch was relatively easy to pinpoint and soon the Trimble was set up gathering its allotted data. 

Gathering data at the bwlch of Nyth Grug

Ahead of us lay the greened grazing slopes of Nyth Grug; our high point of the day.  These we followed ever upward, joining the fence that follows the broad ridge until we spotted the trig pillar and then made a direct beeline toward it. 

Having chosen the spot for Trimble placement and set the equipment to gather data I sat with Linda beside a fence looking down to a single wind turbine lazing in the sun.  It was good to be here, the conditions on the lower parts of the hills were proving warm, but on the tops a breeze blew which helped, otherwise the whole day may have been uncomfortably hot. 

Gathering data at the summit of Nyth Grug

Once the allotted data were gathered and stored we headed down the southerly ridge of Nyth Grug helping two lambs on the way, one that had got itself wedged behind a gate and the other whose head was stuck through a part of a wired fence.  I grabbed each by their fleeced coat and lifted them free and watched them shoot off to their mothers, the first jumping in the air as it did so. 

Trapped behind a gate without the knowledge of a reverse gear

The connecting bwlch between Nyth Grug and Mynd was positioned just beyond a ploughed field in another patch of greened grazing land.  Having followed the remnants of the small stream up from the east I positioned the Trimble atop my rucksack, measured and noted the offset between its internal antenna and the ground at its base and sat on the near bank as it quietly beeped away gathering its all-important data. 

Heading toward the connecting bwlch with Mynd

Gathering data at the bwlch of Mynd

Leaving the bwlch we headed uphill toward a track leading to a gate before veering left and aiming for the higher ground, soon we were on the summit of Mynd.  This summit had been LIDARed, therefore the ten figure grid reference led me toward its high point.  As the Trimble gathered data I sat with Linda chatting away with a bag of crisps in hand.

Gathering data at the summit of Mynd

Our route down led toward a descending fence line that connected with a path beside the southerly corner of the conifer plantation that spreads itself northward up valley.  We were now just a steep field away from the car. 

Before heading to Maesyfed (New Radnor) to visit its old castle, I drove the short distance on the continuation of the rough track that leads toward the visitor car park for the Water-breaks-its-neck waterfall.  Having parked we walked downhill to the stream and then followed a good path beside it to the base of the waterfall. 

Water-breaks-its-neck

I’d only been here once before, many years ago.  Then the waterfall was somewhat of a disappointment as the water was no more than a trickle.  Today it was much more impressive.  It wasn’t roaring down the cliff, but it was beautiful with the greened vegetation of ferns and mosses adding succulent colour to the scene.

 

Survey Result:

 

Nyth Grug  

Summit Height:  538.3m (converted to OSGM15)

Summit Grid Reference:  SO 17050 60690

Bwlch Height:  449.0m (converted to OSGM15)

Bwlch Grid Reference:  SO 17391 61800

Drop:  89.3m

Dominance:  16.59%


 

 

Mynd  

Summit Height:  478.7m (converted to OSGM15)

Summit Grid Reference:  SO 18111 59264

Bwlch Height:  410.3m (converted to OSGM15)

Bwlch Grid Reference:  SO 17772 59659

Drop:  68.4m

Dominance:  14.28%


 

 

For further details please consult the Trimble Survey Spreadsheet