[Jeff Schley]

Not sure.  I read it that the profile was based on SRTM and the 2D/3D Planner was EPQS. Thus the discrepancy was due to EPQS being a little more accurate on elevation per shot, but doesn't include GTTT. We will find out Saturday.

[Bryan Izatt]

Bryan,

Really like what you've done there.  Looks like you used the Install version of Google Earth to get that functionality, I may need to download it again, as I've only used the web version for the last few years.

P.S.  Provisualizer claims they use the USGS Elevation Point Query Service for elevations.

Yes, I use the desktop version of Google Earth.


After trying again to go around Cypress Point hole by hole to look at the elevation changes shot to shot, I couldn't come close to the 152m ascent if I went by their shot to shot numbers and included GTTT from green elevation to tee elevation.  What I also noticed was that the elevations for each hole and tee were dynamic.  One time I tried going around CP hole by hole and it said the data was SRTM and then I tried again and it said it was EPQS.  The 6th tee was 52m in the first try and 44m in the EPQS try.  It's impressive if the Provisualizer is dynamically searching the databases as you enter each hole or change the location of the tees, greens, or any of the three targets. 


The EPQS is a query system that uses a point's latitude and longitude to access the 3DEM database which is lidar based and maybe three times more accurate than SRTM.  However it is very sensitive to the latitude and longitude - they need to be accurate to at least 4 decimal points.  I wonder how they form the EPQS query with lats and longs based on where you set targets on the 2D planner.  Again, an impressive piece of programming, but who knows how accurate.


The 3DEM database is widespread across the US, excluding Alaska.  Not sure how much area it covers in the rest of the world.  Provisualizer for my course in Canada was using SRTM data for example.


So, I'd still take the ascent/elevation data with a lump of salt.


Have fun talking to them and let us know what further information you get.

[Kalen Braley]

Hey All,

Jeff and I spent a couple hours with the creator of the Provisual site yesterday. This has been a side project he's been working on for about 8 years now. A few things of note:

1)  First and foremost the site is intended as a tool for competitive players to chart their way around a course and perhaps build a game plan of how they intend to play each hole.  He said he's had top competitive players reach out to him with questions and requests, as well as coaches and otherwise.  Its intended to be a method to get familiar with a course you haven't played before or perhaps confirm or question assumptions about ones you do know.

2)  Secondary goals are including course meta data like elevations and distance totals, which is what we've been focused on.  He explained how he derived his numbers and its not always ideal due to variances in the access of underlying maps data. The resolution between STRM and EQPS data can be a bit acute (20-30M vs 1-2M).  But it does contain some interesting tools that auto maps to Google Earth flyovers of the course with total yardage and elevation gain/loss, similar to what Bryan created. I'll be doing a few comparisons between courses using Google Earth and his site to see how close it is. A lot can also depend on where the course is located as remote locations such as Ballyneal don't have the same resolution as say Pasatiempo does being in a populated area.

3)  He claims to have about 3000 courses worldwide mapped to date and this is his biggest endeavor/time crunch in building this list for public consumption. The site does have an option for individuals to map a course and provide to him for review and inclusion in his list.  I'll be doing a few of these and hopefully it meets the standards he's looking at for inclusion on the site.

4)  There are a few feature requests we would like and he will accommodate as time and effort allows, but he has fairly ambitious goals of other things to implement like real-time weather, green data, etc. Doing something like a Rigor Factor algorithm isn't really on his radar.

If anyone is interested in mapping a course, please reach out to Jeff and I or check the FAQ section on the site.

Thanks!

Kalen

[Jeff Schley]

To build off Kalen's post my thoughts are similar but would add a few things.

• Simon is a wonderfully giving and accommodating chap, who has put in over 10,000 hours himself, solo all the way to anything and everything provisualizer. I feel guilty using his site as he does this gratis as a passion. Big respect for him and told him to start charging people a nominal amount to request a new course to be mapped. He does all of them himself in his free time. Even a donations button like we have here would prove useful to him.

• I told him to join GCA as he is a golfer himself in the UK and could help answer questions about his site.  Hope he does.

• Some clarifications on the data. As Kalen states the SRTM data is accurate to the 20/30 meters, but EPQS is accurate to the 1 meter so much more accurate. The EPQS data is only available for the courses in the USA when you select the 2/3D mapper option. The international 2/3D mapper is using SRTM data, which isn't very accurate comparatively.

• The real interesting option is exporting the premapped course option to Google Earth and then calculating the course elevation profile. This is very interesting and while we aren't sure how Google is getting their information for their mapping, it most likely is pretty accurate and maybe as good/better than EPQS. This will be compared to EPQS data for our US courses as Kalen said and we can extrapolate out of that how close they maybe.

• The real immediate value would be, as I see it, is using the export course to Google Earth are the international courses. This is going from SRTM data to something much more accurate and would like to put some work in there as we can really improve our data there from provisualizer.

• We have discussed PV adding the rankings designation, where you can sort by Top 100 of some list. He does this for Ryder Cup courses or US open courses etc. So this could provide some value for those like us.

• As Kalen states it would be nice to get some of us to volunteer to map some courses for him as a way of saying thank you. I'm also interested in doing some pilot testing of some courses with Kalen to dig into the differences of SRTM/EPQS/GE options. Then decide to maybe utilize the export to GE and use that as definitive data.

So long story short, my data in what I presented isn't accurate enough to give us anything more than a starting point. However, I think we have an opportunity to vastly increase the accuracy via the exporting data to GE and using the elevation profile there, but will take work from our side. If you would like to participate let us know as we will be discussing potential project scope soon.

[Jeff Schley]

Ok I have an update on this project. I have mapped the Top 100 using Google Earth data now and incorporated that into a spreadsheet. This is extracting out the PV Show Profile Line (which is the line one walks straight down the fairway and GTTT) overlayed onto Google Earth. This has presented some very interesting data.

Some disclaimers first as this group is persnickety.

• The Top 100 is actually 98 as St. Patricks and Les Bordes courses aren't in the Google Earth system yet to map.
• PV was a great start and a view into what data is out there from publicly available sources. We realized the data from the Elevation Profile for each course is based on SRTM data, which isn't the most accurate perhaps, but a start.
• When doing the 2D/3D tour of a course you get EPQS data for US courses, which is an improvement, but you don't get the GTTT's.
• Google Earth data when overlaying the PV Show Profile Line yields data for all courses in the world in the same methodology.  However, we DON'T know exactly what that is and how accurate it is compared to the SRTM/EPQS data. We do know it is standard around the world for all courses (as best we can tell) and would be surprised if it isn't as good as EPQS data.
• What I have is the SRTM data vs. the GE data. We know SRTM isn't the most accurate and the imaging of the GE is very good as we all know. So I'll present the findings so far below.

I'm having a zoom call later this week for anyone interested to discuss what is/isn't important, just PM me if you want to join.

Here are some quick take aways and I have posted the top 10 courses full data below (although we know the formatting sucks).

• The total elevation difference of highest to lowest varied very insignificantly only .28m for all the Top 100 so this doesn't vary much between SRTM and GE.
• Where there is ALOT of difference is the total ascent. Some of this isn't surprising as the SRTM doesn't include GTTT. On average GTTT is about 15-20% of the length of a course. However GE finds that the Total Ascent is 84% higher than the SRTM data. BIG jump.
• The biggest outlier for a huge jump in total ascent is Ballyneal. SRTM has it at 65 and GE at 184. Again SRTM doesn't include GTTT for total ascent calculations so not a surprise for it to be higher, but 322% higher. I think this is magnified due to the poor mapping of SRTM data in the middle of nowhere as well. Whereas GE is much more detailed.
• Total walking distance (course plus GTTT) was another area I compared and SRTM to GE which isn't significant. SRTM was on average .4% longer in it's distance. In PV course elevation profile they list the entire SRTM data including GTTT, it is only ascent where GTTT aren't factored in.
• An area I want to explore more is the average slope of a course which GE captures. Not sure how to use it yet, but it will be handy I think when trying to do a Rigor Factor algorithm. Average slope X distance = who knows what. If anyone has ideas let me know.

Thoughts?





 

21-22 Golf Mag Top 100

Provisualizer - SRTM Data

Google Earth Data

Comparisons

Rank

Course

Total Ascent

Elev. Diff.

Ascent > Elev.

Play Dist.

Walking Dist.

Tee Dist.

% over

High

Low

Diff

Ascent

Descent

Max + slope

Max - slope

Avg + slope

Avg - slope

Dist. KM

Dist. Yards

Diff. Dist. G-T

Dist. % Diff.

Elev. Diff. D-L

Total Ascent Diff. C-M

PV Ascent   % less X3/E3

1

Pine Valley [/t][/t]

105

29 76 7165 8191 1026 114%

54

27 27 156 154 20.1 15.3 3.8 3.4 7.45 8147

44

0.53%

2 -51 -67% 

2

Cypress Point [/t] 152 50 102 6588 7610 1022 116% 45 2 43 217 220 26.2 36.8 4.9 5.8 6.97 7622 -12

-0.16%

7 -65 -64% 

3

St. Andrews TOC[/t] 40 7 33 7292 8616 1324 118% 9 1 8 44.3 39.9 3.8 3.9 0.9 1.2 7.81 8541 75

0.87%

-1 -4.3 -13% 

4

Shinnecock [/t] 97 19 78 7473 9083 1610 122% 25 2 23 126 134 15.9 20.2 2.5 3 8.27 9044 39

0.43%

-4 -29 -37% 

5

NGLA [/t] 70 17 53 6932 7924 992 114% 18 0 18 125 124 17.6 13.3 2.9 3.1 7.2 7874 50

0.63%

-1 -55 -104% 

6

Royal County Down[/t] 54 10 44 7124 8513 1389 119% 14 6 8 54.3 51.9 7.3 5.5 1.3 1.2 7.73 8454 59

0.70%

2 -0.3 -1% 

7

Royal Melbourne West[/t] 60 12 48 6655 7790 1135 117% 43 27 16 107 107 15.6 11.3 2.7 2.7 7.09 7754 36

0.47%

-4 -47 -98% 

8

Oakmont[/t] 125 27 98 7286 8842 1556 121% 307 275 32 187 190 28.5 27.8 4 3.8 8.06 8814 28

0.31%

-5 -62 -63% 

9

Augusta National [/t] 136 55 81 7558 8897 1339 118% 104 51 53 196 202 14.3 18.3 3.9 4.7 8.1 8858 39

0.44%

2 -60 -74% 

10

Sand Hills [/t] 92 22 70 6955 7993 1038 115% 1024 1001 23 172 173 17.6 22.1 3.8 4.1 7.3 7983 10

0.12%

-1 -80 -114% 

[Jeff Schley]

Copy and pasting isn't working well apologies. If you want the spreadsheet I'll happily email to whoever requests via PM. Some quick course stats according to GE data.
Top 5 courses for Total Ascent (in meters)

• Kawana - 272
• Rock Creek Cattle - 246
• Peachtree - 225
• Cypress Point - 217
• Sleepy Hollow - 217

Top 5 courses for average + slope (in degrees)

• Kawana - 6.1
• Rock Creek Cattle - 5.1
• Peachtree - 5.1
• Crystal Downs - 5
• Sleepy Hollow - 5

Top 5 courses for difference of highest point on the course and lowest. Most elevation change in meters.

• Rock Creek Cattle - 118
• Ardfin - 76
• Ellerston - 72
• Crystal Downs - 62
• Olympic Club - 59

Top 5 courses with least elevation change.

• Royal St. George's - 3
• Royal Lytham & St. Annes - 5
• Portmarnock - 5
• Royal Liverpool - 6
• Kiawah Island Ocean - 6

Top 5 longest walks including GTTT (in yards), not much change from PV data.

• Kiawah Island Ocean - 9711
• Diamante Dunes - 9230
• Inverness - 9208
• Whistling Straits - 9186
• Ellerston - 9143

Shortest 5 walks

• Swinley Forest - 7273
• St. George's Hill - 7349
• Utrechtse De Pan - 7415
• North Berwick - 7458
• Myopia Hunt - 7502

Comparisons between PV and GE
Top 5 courses which gained the most Total Ascent with GE vs. PV.

• Ballyneal - 322% 119m gain
• Muirfield Village - 298% 134m gain
• Royal Troon - 288% 51.9m gain
• Ohoopee Match Club - 281% 101m gain
• Royal St. George's - 280% 70m gain

There were 10 courses which actually were higher using PV Total Ascent vs. GE.

• Woodhall Spa - 24% 12m gain
• Garden City - 22% 11m gain
• Baltursol - 13% 10m gain
• Lahinch - 12% 8m gain
• Barnbougle Dunes - 10% 5m gain

Good for now.

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