[DMoriarty]

Bryan,

The benchmark issue extends beyond just the accuracy of the USGS benchmark.  We don't know what benchmark they used.  And even if they did use the USGS benchmark, the surveyors still had to get the correct information to the site.   I understand why you want to say "off" but I am comfortable saying they were "wrong."  When it comes to the absolute (vs. relative) elevations, I'll go with the USGS.  

As for that list of differences, those are some numbers I quickly provided to Jim to give him an idea of about what I was talking. The absolute value problem, as I call it, was predicated on the elevations on the 1913 topo conflicting with the elevations on every other map I have seen, especially the Quads, as well as conflicting with the 1/9 NED data, especially where the NED data is of higher resolution.   (I should have picked such points for Jim, and after looking at the informaitonI don't have tremendous faith that all those readings are exact, but I expect them to be reasonably accurate.

As for calculating the delta, yes it will be very difficult to do which is what I have been saying.  But for starters we can look at the absolute elevations of the some of the major features on the property.  For example the ridge that runs along the 6th fairway, the ridge that runs approximately along the 9th fairway, and the ridge that runs along the 13th fairway.   We may not be able to match things up point for point, but we can determine how high the ridges are now, and compare that information to the 1913 Topo.  

I understand your current theory, but was referring to when the 1913 Topo was first introduced into this part of the discussion.  I thought someone had tried to use the 1913 topo to say the 6th tee was higher than the reading on the Quad, and either the quad was wrong, or the fairway had been leveled.

As for your theory, we agree with that if the camera view included the 3rd tee and 2nd green, then the ridge would block the view.  I also agree that if the camera was aimed almost entirely to the right of the ridge on which the 3rd tee and 2nd green sit (so that they were out of the frame,) then that ridge would not block the view.   But I reject the notion that the photo was taken  of a narrow cross section of the downslope of the 4th fairway.    
___________________________

Do you not have enough confidence in the USGS quads or 1/9 NED to do this determination?  The 1913 topo is not necessary for that analysis.  I believe I stated in one of my analyses based on USGS data that the relative differences in the ridges from the 1913 topo could be used but wouldn't make much difference.  Of course you are precisely right that the topo doesn't cover the far side of the tracks so there is no way to do the complete analysis based solely on the 1913 topo.  Is that really what we are debating?

I am comfortable using the USGS quads.  Less comfortable with the 1/9 NED until we get some clarification on what is happening where the resolution is lower.   I know I did a x-seciton with the 1/9 NED, and it is probably fine, I'd just like to know more about the data and what the application does when there is missing data.  

I am not sure what we are debating   You seem to be the driving force in this discussion, not me.   It seems like you and I agree to much of this, so I am a bit at a loss.
________________________________________

I agree.  But, why can't we do the analysis from the USGS topos.  What does the difference in absolute elevations have to do with that analysis.  It's a red herring.

I was just trying to answer Jim's question, which I took to be about the 1913 Topo.  I am fine with the USGS topos.
___________________________________

As for the typo, we can probably line it up enough to have a discussion.  Again, I was thinking in terms of the issue of visibility.
___________________________________

As for notes on the topo about how it was created, I remember something about that from long ago; something about one technique was used on one side of the ridge and one technique on the other, or something.  I'll have to see if I can find it again unless you know what it said.
____________________________________

As for the 1/9 NED . . .
-- There is quite a bit of missing data from that section, I think.  Select the bottom choice (colored elevation) and the 1/9 NED only and you can see green swatches which I think means wherever there is large enough gap in the data.
-- I do not think that the data defaults to 1/3 NED if no 1/9 NED is available.  The specifications don't say anything about this.  I'd be more comfortable if it did default to a different set, but I don't think that is the case, because there appears to be quite a lot of data missing or of lower resolution.
-- I know the specifications say it is 1/9 data and they provide the identifying grid, but I cannot tell from the specifications how complete the sample is.  Reading about how this works, it sounds as if there are sometimes gaps or missing data that have to be filled in by another sampling, so I have low confidence that there is ample 1/9 data in the low resolution areas and especially in the "green" areas.
-- If you just want to test the ability for it to check fine contours, why not do the driving range, only with smaller contour intervals?  It seems to be fairly high resolution.  Also, most of the 7th hole seems to be fairly high resolution, with the exception of some spottiness in HHH.  Bryan should know the course well enough to know if a contour matches on the 7th.  
_________________________

 Sure, I'll try, but I'm not sure where you are trying to see.  When you mention 9th hole and 18th tee, do you mean where they are now, or where they are marked on the map.  The 9th green is at the top, for instance.

I was referring to where they are now.  Generally I am looking at the ridge to the East of the finger shaped pond.  

[DMoriarty]

As to your last question,  

1.  I don't understand how the photo could be of the 3rd tee and 2nd green as the caption states, for reasons discussed.  I am leaving open the hope that someone will come up with something we haven't considered, but I am not holding my breath.

2.  I feel like if the caption is wrong about these two things, then this is good indication that Brown or whoever wrote the caption was just interpreting/guessing same as we are, and so I don't feel any compulsion to stick to the 6th green when trying to place the photo, especially because I see a building, a few roads, and some other interesting features that I don't think fit over there.  And I think the photo was taken from above the ground.  

3.  I don't have a strong belief from where the photo was taken, but I am still considering it.  From the water tower or near there works much better than the 6th fairway to me, but there are some problems with this view as well.

4.  I still think that the photo "from the 3rd tee" and the photo "from the 6th green" look like they were taken from close to the same location (one from elevation, one from not.)  

5.  I am close to satisfied that I am not going to figure out from where the photo was taken.   This really ought not surprise me or anyone, since I have never been there.   Interesting to try though.

[Patrick_Mucci]

Jim,

To the best of my knowledge and testing, none of the USGS maps have enough resolution in elevation to pick out the elevation of the RR track as opposed to the immediately surrounding land.  

Generally speaking,

Parallel to the 17th fairway, the RR tracks are BELOW grade.
Parallel to the 18th fairway, the RR tracks are ABOVE grade.

I agree with this generally.  But the same would be true of the 1913 Topo, even if its survey lines extended through the tracks (they don't.)  It is still a matter of connecting the data points, and that requires some extrapolation, whether by field sketch or algorithm.  And we have no idea where the data points were for the 1913 Topo, or even how far apart they were spaced.

That all said, if we ever get a complete 1/9 NED data, we will probably be able to tell get very close.  
______________________________________________

Bryan,  Do you mind confirming a few readings for me off the 1913 Topo?

I am trying to read the elevations for the ridge as it runs generally down the 9th hole and generally toward the 18th tee.   I am getting that the entire ridge is between 155 and 160 ft, except of for the little oval at or near the left green on No. 9 marked "top of ridge." This section is at 160 ft. or over.  Correct?  

David, the 9th tee sits above the land between the tee and the green, with the green probably slightly below the tee, however, the 18th tee and back of the 17th green, sit above the 9th green.

I am also trying to follow the 150 line,  which seems to extend almost all the way to the RR tracks; more specifically to the point near the current 18th tee which is marked by a number of survey lines intersecting.   Is this what you see as well?  

The current, non-championship tee sits above the 9th green.

Let me know which elevation points you want readings on

[Bryan Izatt]

As to your last question,  

1.  I don't understand how the photo could be of the 3rd tee and 2nd green as the caption states, for reasons discussed.  I am leaving open the hope that someone will come up with something we haven't considered, but I am not holding my breath.

On this point I agree and have for some time.  If somebody could get a picture now, along that line that shows a further ridge, that'd be the only thing that I can think of that would prove the point.

2.  I feel like if the caption is wrong about these two things, then this is good indication that Brown or whoever wrote the caption was just interpreting/guessing same as we are,   I wouldn't be surprised either.  The tees and greens and fairways weren't there when they took the picture.  It would have been tough for the cameraman to know exactly what they were looking at.  They'd have the same difficulty we do if it was done well after the fact.  and so I don't feel any compulsion to stick to the 6th green when trying to place the photo, especially because I see a building, a few roads, and some other interesting features that I don't think fit over there.  I have stated where I think the camera was, and I don't think it was the 6th green.  Honestly, I don't really see the things you see, but feel free to explore it further. And I think the photo was taken from above the ground.  I'm not convinced.  Let's agree to disagree and move on.

3.  I don't have a strong belief from where the photo was taken, but I am still considering it.  From the water tower or near there works much better than the 6th fairway to me, but there are some problems with this view as well.

It doesn't work for me, but if you find something further I'll be happy to reconsider.

4.  I still think that the photo "from the 3rd tee" and the photo "from the 6th green" look like they were taken from close to the same location (one from elevation, one from not.)  

5.  I am close to satisfied that I am not going to figure out from where the photo was taken.   This really ought not surprise me or anyone, since I have never been there.   Interesting to try though. 

I am comfortable with my siting of the picture.  That's no surprise to you.  The off-line peanut gallery can continue to pursue their desire to fit it one way or another to the caption.  You can continue to look at alternate locations.  The world will continue to turn.  And, sure, it was a good learning experience. I learned a lot about surveying and topo maps, even if we don't agree on some of those things.

[Bryan Izatt]

David,

As to the topos and absolute elevations and contours, I am quite perplexed about the 1/9 data.  Sure, some of it appears to be missing around PV, but they populate those areas somehow.  Surely, it must be from the 1/3 data.  Seems unlikely to me that they just interpolate from whatever 1/9 data they do have.  They've been surveying for a long time.  There will have been previous surveys, including Crump's that would have provided input to the NED before there was even 1/9. Hard to believe that the download data set metadata would erroneously label interpolated data as measured real data.  If you come up with an answer, let us know.

As to the absolute difference situation, I can only conclude that the 1/9 data contributes to the differences as does the 1913 topo.  I tried the 7th green area that I think you'd agree looks like has valid 1/9 data and basically got very little elevation contouring at all.  If that green is flat and the bunkering is more or less level with the green then maybe the contouring is correct.  Jim or Pat could comment on what the green area looks like.  

I also tried the 12th green and fairway at Merion where the data looks solid in the shaded map. As you zoom in, the shaded map pixelates badly at 1:2159 (1" = 180 feet or so) suggesting to me that the data doesn't support elevation profiles at that level of resolution that well.   I tried a 2 foot, 3 foot and 4 foot contours.  They didn't look all that good to me.  Others who are more familiar with the terrain can comment.  This is the two foot contour.



Again, I am left questioning the validity of the data to provide the resolution we're looking for.  That lack of confidence translates into the absolute values of the USGS data.  I just don't accept, at the moment, that the 1/9 or the USGS quads provide an absolutely accurate absolute elevation that we can trust.  And, I still don't agree that the comparisons of absolute elevations across a century id proof positive of anything.  Let's agree to disagree and move on.  If you find something that explains what is going on with the data at that specific location, let's reconsider.

With what we know now, I'm still comfortable with the 1913 topo being a reasonable representation of the contouring of the land at that time.  It was professionally done.  Surveyors then knew how to survey. It's not rocket science (which LIDAR actually is closer to  )  and if you know what you are doing it's hard to get it wriong.  Now, maybe this surveyor was incompetent, or was drunk on the job, or .........................

In the circumstances, I feel comfortable using those contours to try and discern what Crump et al might have seen on the ground that contributed to the way they designed the course.



 

[JESII]

Bryan,

The 7th green and surrounds are pretty flat...in that I wouldn't be surprised if there were no 5 foot contour lines but I would be surprised if there were no 2 foot lines...which did you use? The bunkers are somewhere on the order of 4 feet below the edge of the green with the perimeter of the green being the high point as you go around so perhaps the bunker bottom is only a foot or two below the low point of the green which is center/left-center. The 12th at Merion looks reasonable on a quick glance.


David,

I agree with you that whoever wrote the caption likely guessed the same way we are with one caveat...the person who took the photo was there and knew what the land looked like in that state of clearing and development. I've thought all along that the camera was located close to the corner of the dogleg. There is a small spruce tree there, if you go South from it 20 or 25 yards and direct the center line of the picture at the right edge of the current 4th fairway what are the results? Can the far hills be seen better? What would be the left edge of the picture based on your understanding of the common radius' at the time? I believe this provides a substantially different relative elevation than the third tee although the third tee may still be in the left edge...maybe not.



Pat,

Are you quite certain the 9th tee sits at a lower elevation than the back of the 17th green and the old back tee on 18? You type it with typical self assuredness...

[Patrick_Mucci]

Jim,

I mistyped,  meant the 10th tee and 10th green.

[Bryan Izatt]

Jim,

Here are the contours for the 7th green area.  It doesn't seem to capture the bunkering contours to me.  What do you think?

[DMoriarty]

Bryan, any luck on deciphering the elevations on the 1913 Topo on the ridge to the right (east) of the finger shaped pond?  It looks to me like the contours on the 1913 map run around 10 ft. higher than the contours on the latest quad.   Can you confirm this?

As to the topos and absolute elevations and contours, I am quite perplexed about the 1/9 data.  Sure, some of it appears to be missing around PV, but they populate those areas somehow.  Surely, it must be from the 1/3 data.  Seems unlikely to me that they just interpolate from whatever 1/9 data they do have.

Look at the summary that came with the download.  It says nothing about substituting a different data set when the data is spotty.  It describes the downloaded data as 1/9 data.  I don't think they'd substitute 1/3 NED or 1 NED data into a data set, and I think they'd say if they did.  If you wanted to check it you could download two sets of data from a sample area where the 1/9 NED appears to be missing, but the 1/3 NED data appears to be present (one of the green areas.)  If the results are different between the samples sets, that that might give us some idea of whether the default automatically defaults to the next lower resolution.   (I'd do it myself, but the Mapper won't run on my computer.)

Hard to believe that the download data set metadata would erroneously label interpolated data as measured real data.  If you come up with an answer, let us know.

First, wouldn't it be erroneously labeling it if it was giving you 1/3 NED when it claimed to be giving you 1/9 NED?

Second, I am not so sure it is erroneously labeled.   You downloaded the dataset, and the label identified it as 1/9 NED data and provided you with the parameters of the collection area.  I suspect you downloaded all the 19 NED data from that area, even if it was noisy and incomplete.   You then plugged that raw data into Global Viewer, and Global Viewer extrapolated from the data set to provide you with contours you are creating. In other words, your contours are a creation of Global Viewer, and may well reflect how Global Viewer deals with an incomplete or limited dataset.  
    Same goes for the rasterized image of the data on the USGS viewer.   It may have some extrapolation method to deal with missing data.  If there is enough missing data over a certain area, then it appears the USGS reader leaves the area blank.  (Thus the clear or green areas.)   It looks to me like if there is some missing data or noisy data, then the viewer creates a blurry, less focused image (see the ridge near the 3rd tee for example.)   Where the data set is complete or nearly complete then the image appears sharp at least at a certain scale.  

I think the key point that you may be overlooking is that 1/9 NED is NOT A MAP.  It is raw data.  It is a dataset of elevation readings taken in a grid pattern with approx. 3 meter spacing between data points using LIDAR technology.   This data can be used to create a map (as the USGS does in their viewer and as you do with the Mapper) but this must require some extrapolation, especially in a situation like Pine Valley where it looks like there is plenty of missing data and/or unusable data.  

As to the absolute difference situation, I can only conclude that the 1/9 data contributes to the differences as does the 1913 topo.

While  interesting, I don't think your experiments in extrapolating contours have much to do with the ability of the USGS to collect accurate readings using LIDAR technology.  I agree that we may not be able to rely on elevations from areas missing data (green areas and low resolution areas) but nothing you have done convinces me that there is anything wrong with the data from higher resolution areas.   I expect that data is what the USGS says it is, accurate to within +/- one meter.  

I also tried the 12th green and fairway at Merion where the data looks solid in the shaded map. As you zoom in, the shaded map pixelates badly at 1:2159 (1" = 180 feet or so) suggesting to me that the data doesn't support elevation profiles at that level of resolution that well.   I tried a 2 foot, 3 foot and 4 foot contours.  They didn't look all that good to me.  Others who are more familiar with the terrain can comment.  This is the two foot contour.

While I agree with your conclusion that this data doesn't support the kind of small scale elevation profiles for which you were apparently hoping, this paragraph more than anything else convinces me that we have very different understandings of what is ongoing with this data set.    

1.  Pixelation.   Of course it badly pixelates!  If it didn't pixellate I'd have less faith in the viewer's ability to accurately portray the data, rather than more faith.  It would mean that there was a large amount of extrapolation ongoing with the data!  Remember that even ith the LIDAR technology and a full dataset front the sample area, our data points are still about three meters apart!   So ideally the "pixels" in this case are 9 square meters (3x3 meters) each containing ONE elevation.  Those are damn big pixels, wouldn't you agree?   And as the scale decreases, those pixels become even bigger.  Zoom in a bit more and you can see the individual tiles (pixels.)

2.   12th Green at Merion.  Like Jim, I think the contour map at Merion looks pretty good.  Better than I expected.  Your contour map not only captured the general flow of the land, it also captured the bunkers, the ramparts in front of the bunkers, the steep slope off the right of the green, even the green slope (that green is wickedly sloped.)  
      Keep in mind that the green and green side bunkers fit easily in a 50 meter by 50 meter square, which means we are only talking around 16 or 17 data points across.  The left bunker is between 4 and 7 meters across, so on the horizontal scale it may only catch one or two data points.

Here is a grey scale image capture of the high resolution photo of that green, reduced to 18 x 18 pixels, then recaptured and enlarged, followed by the same image only smaller.  

     

That is about the level of "resolution" we are dealing with here, although not surprisingly Photoshop's grayscale gamut is much better equipped to deal with differences in shade than is the USGS viewer able to deal with subtle variances in elevation.  The white bunkers help a lot.

So I'd say there are two things that are ongoing here.   First, you seem to be standing too close to the Monet. Second, you are confusing that lack of resolution caused by standing too close with a lack of accuracy of the individual data measures.   Better resolution does not mean that the collection of data at each point is more accurate, it merely means that the the data points were closer together.

[DMoriarty]

David,

I agree with you that whoever wrote the caption likely guessed the same way we are with one caveat...the person who took the photo was there and knew what the land looked like in that state of clearing and development.

I agree with your caveat, and would add that I would have much more faith in the caption if we knew it was written by someone who had been there when the photo was taken.  But the Brown book was published until 50 years after the photo was taken, and I don't think we know when the caption was written or from where the information came.

I've thought all along that the camera was located close to the corner of the dogleg. There is a small spruce tree there, if you go South from it 20 or 25 yards and direct the center line of the picture at the right edge of the current 4th fairway what are the results? Can the far hills be seen better? What would be the left edge of the picture based on your understanding of the common radius' at the time? I believe this provides a substantially different relative elevation than the third tee although the third tee may still be in the left edge...maybe not.

Not sure I understand your instruction.  From 20-25 yards south of the spruce the camera would be shooting at an angle across the 4th fairway, so I am not sure what you mean by right edge of the current fairway.  From that point one could aim over anywhere from the beginning of the fairway all the way to the green and still be lining up over the right edge of the fairway.  

But generally as the camera is rotated to the right (counter-clockwise) the intervening ridge becomes less of an issue for two reasons.
1.  On the intervening ridge (with the 3rd tee, 2nd Green and 4th fairway) the ground gets higher to the left (toward the 3rd tee)  so we have more clearance as we rotate the camera to the right.   (That is a long winded way of saying we would be looking more down the valley.)
2.  As for the distant hillside, the distant hills generally tend to get higher as we pan to the right.  

So we not only have more clearance as we pan right, we have bigger hills in the distance.   So we'd see more of them.

Does that make sense?  

As for angle of view of the camera and such, I think Bryan and I would agree that we don't know.   To me it doesn't matter much, because the distant tree covered hills are visible all the way to the left edge of the photo.  Lining up the angle to the right of there doesn't answer the question of why we can see hillside in the background all the way to the left edge.  

All that said, I do agree with Bryan that it may have been possible to cut the 3rd tee and 2nd green out of the photo and get visibility of the hills beyond.  I just don't think that is what we are seeing in the photo.

[JESII]

All that said, I do agree with Bryan that it may have been possible to cut the 3rd tee and 2nd green out of the photo and get visibility of the hills beyond.  I just don't think that is what we are seeing in the photo.

David,

I don't understand this comment. You agree that it may have been possible to have the camera looking over the lower elevation to the right side of the intervening ridge at higher elevation hills in the background..."but you don't think that is what we are seeing in the photo". I'm fine with everyone's ability to form an opinion and I know the structures and other items you've made visible through enhancing the picture make you think it's of a different part of the property but...well, I just don't understand the comment. Perhaps we'll learn more of what you're thinking on this.

Regarding the Brown picture and its first known appearance 50 years after the fact, fair enough. I can't very well claim the Crump in the woods on Pine Valley's eventual property picture is a myth based on Pat hoping there's an inscription on it then disagree with you on this one but for what its worth the landforms hold a strong resemblence in my opinion and the Crump picture bears absolutely zero unique qualities for identification.

The angle I was asking for on the 6 to 4 (and 2 and 3) picture would to the right edge of the fairway at about the top of the ridge. The left edge should still go to the area between 2 green and 3 tee and in the picture there really isn't much of the far hill showing and it's fair to assume they built up the green and tee over there so I think it would work.




Bryan,

That's cool technology but it's strange because there is a not-too-subtle rise out of the bunker all the way around that is 2 feet at its smallest and 4 or 5 feet at its greatest in terms of absolute rise from the edge of the sand nearest the green up to the apron as it goes around.


Pat,

I thought I had you...

[Patrick_Mucci]

Jim,

What I don't understand is why everyone's ignoring the rising shoulder that appears in the right side of the JAB/Shelly photo.

That would seem to be the footpad or slope that the 5th green and 6th tee are built into.

[Patrick_Mucci]

So, what could be seen, riding eastbound, at 60+mph, looking south ?

[Patrick_Mucci]

Jim,

Here's an aerial taken in the winter.

Please note the green trees (pines/spruces) intervening between the 6th fairway and the 4th fairway, 2nd green and 3rd tee.

[Patrick_Mucci]

Jim,

Here it is, blown up a bit.

[JESII]

Pat,

Do you have any way to confirm the date of that aerial?

[JESII]

Jim,

What I don't understand is why everyone's ignoring the rising shoulder that appears in the right side of the JAB/Shelly photo.

That would seem to be the footpad or slope that the 5th green and 6th tee are built into.

Because it could be any slope in the world when the camera is at the top and looking at an angle. The low right side of the camera view will show that type of "shoulder".

[Patrick_Mucci]

Jim,

What I don't understand is why everyone's ignoring the rising shoulder that appears in the right side of the JAB/Shelly photo.

That would seem to be the footpad or slope that the 5th green and 6th tee are built into.

Because it could be any slope in the world when the camera is at the top and looking at an angle. The low right side of the camera view will show that type of "shoulder".

Not if you understand the topography of the ridge and area immediately below the ridge for the entire length of the hole.

[Patrick_Mucci]

Pat,

Do you have any way to confirm the date of that aerial?

Yes,

April.

[DMoriarty]

I thought I'd take a shot at demonstrating what is happening with the 1/9 NED data, following Bryan's lead and using Merion's 12th green.

Here is an image of part of the 12th green, and next to it is the corresponding NED rasterized image from the USGS Viewer:



The rasterized image does not look like much, but at this scale we can see the individual tiles.  (According to the Viewer's ruler, each tile measures a bit less that 3x3 meters.) There are 23 tiles across bottom of the image, so I assume 23 data points.  Using the Viewer's elevation function, and clicking at different parts of the various tiles, one can see that each tile represents single, unique elevation.  So by a round-about methodology, I think we are down to single data points.

As for the grayscale scheme, the various shade of gray do NOT seem to represent distinct elevations.  Rather, the shades seem to represent the magnitude of the delta between the data-tile and the neighboring data-tiles.  The darker the shade, the more abrupt the change.   So the abrupt elevation change makes the bunkers look almost black. This is one reason I think it is hard to read close up.]

Here again is the photo image, this time with the rasterized image created with 1/9 NED layered over the top.  We can see how the "data-tiles" (for lack of a better term) line up on the image:

        


Below the image is a column bar chart providing a rough, un-extrapolated, unsmoothed, cross-section of the bottom row of tiles across the bottom of the image.  As you can see, the data-tiles appear to be picking up even relatively small differences in elevation across these 23 data-tiles.  One could fill in all the datapoints and come up with a elevation rendering of the 12x23 data-point area, but that would be rather tedious.  

Here is a closer look at what I believe is the actual raw data represented by each data-tile along the bottom row, from left to right.  I've also included a description of what we see in each data-tile.

310.51  Rough
310.26  Rough
309.55  Rough
307.80  Rough/Bunker Edge
305.13  Bunker Edge/Bunker
303.31  Bunker
305.08  Bunker/Bunker Edge
306.83  Green
306.32  Green
305.72  Green
305.13  Green
304.54  Green
303.91  Green/Bunker Edge
301.17  Bunker Edge/Bunker
298.71  Bunker
298.66  Bunker/Grass Island
298.21  Grass Island
295.92  Grass Island/Bunker
295.76  Bunker/Bunker Edge
295.90  Rough
294.71  Rough
293.53  Rough
292.34  Rough

So we have about a 6 or 7 foot drop from the left rough into the left bunker, then a rise about 3 1/2 feet back up to the green, then a green sloping slightly and smoothly toward the right bunker, then a drop of 8 or nine feet into the right bunker, then not much of a rise out of the bunker on the far right rough, then the ground continuing to slope.    I am not sure if this is exactly what is there in terms of the ft. drop, etc.  I think Jim should be able to confirm that this is pretty much what is happening on the ground, considering that there aren't that many data-tiles relative to the features such as the bunkers.  For example there was only one data-tile each totally in each of the bunkers.  Who knows it if it at the low point for this line.

As importantly, we can see that there isn't necessarily a correlation between the actual data readings and the the Global Viewer's ability (or lack thereof) to created extremely accurate contours depicting relatively small areas with the 1/9 NED.   The accuracy of the actual measures is dependent upon LIDAR technology, and according to the USGS the data readings themselves (what I call the data-tiles) ought to be accurate to within +/- 1 meter.  (I suspect it is more accurate than this, but that is the standard they provide.)

Now all this is just me trying to figure out how the 1/9 NED is depicted on the Viewer.  I could be wrong and am as always open to comments and suggestions.  
______________________________________

ADDED:  So above is how I think it is supposed to work.   The trouble is finding locations on the PV area where it will work.   I think that we can at least find higher resolution areas, but perhaps not as clear as the data for Merion.  But it is difficult to tell what data points are real and what are extrapolations.  It may be a matter of waiting until if/when the USGS supplements this particular data set.

[Bryan Izatt]

Bryan, any luck on deciphering the elevations on the 1913 Topo on the ridge to the right (east) of the finger shaped pond?  It looks to me like the contours on the 1913 map run around 10 ft. higher than the contours on the latest quad.   Can you confirm this?

.............................

Here are three  contour maps in that area.  The first one is the 1/9 NED data (Gold) compared to the NJ State Atlas Quad contours (Red).  Draw your own conclusions.  




This one compares the NJ State Atlas Quad contours (Red) to the 1913 Topo (Black) to the best of my ability to pull them off the picture of the topo and fit them to the aerial.  This aerial is from the Seamless Server Viewer.  Yes, the 1913 topo is generally 10 or so feet higher.  The contours are reasonably similar. At least as good as the comparison of the two current USGS contour maps.





Finally, here is one with all three  together.

[Bryan Izatt]

Pat,

Do you have any way to confirm the date of that aerial?

Yes,

April.

Hmmm, deciduous trees already in leaf in April in NJ?

Here is a higher resolution aerial.  Don't know the month, but it is clear that much of the forest between the 6th green and 3rd green is deciduous.  You can see the shadows of the tree trunks.  There's pines in the grove between 2nd and 3rd greens.  And deciduous behind the 3rd tee.

Why don't you take your camera and take some pictures now or in January from the 6th green looking over the 3rd green to the 3rd tee.  It would be convincing if you can't see through because they are all pines.

[Bryan Izatt]

And, I thought I was nuts doing all this contour mapping.  But, the analysis below takes the cake.  You win the nut award. 

This is what Global Viewer does with the downloaded dataset.  The dataset contains the data at the pixel level you manually measured.  Global Mapper maps it at whatever custom intervals you'd like.  It is a better tool for looking at elevations and contours than the Viewer is, in my opinion. 

The shadow viewer in the seamless map is not very useful on a micro scale, although it strikes me that where the data is good, it looks somewhat like the CBM plasticine models, only in two dimensions with shadowing simulating the third dimension.  I don't think that the Viewer rendering and LIDAR data is going to replace hand surveys and contour maps in the near future for golf course designing.  Like all technology it has some maturing to do and it needs to be customized for particular applications like golf course design.

Based on three locations I've looked at at PV, I'd draw the conclusion that the data there doesn't support the level of elevation precision that we're looking for.  I think it is older, non LIDAR, data in some areas.  I don't think it is an interpolation of missing data. There is obviously interpolation to get elevations at every clickable point, but the interpolation is probably from the best available data at whatever horizontal resolution was available.

In any event, I remain skeptical about the absolute precision of the USGS data around the PV site.  I think it is fallacious logic to suggest that the data represents a certain benchmark against which the 1913 data can be compared.  The datums are undoubtedly different and the measurements in each method are probably somewhat off, by amounts we don't know.  Trying to say that the 1913 is wrong on the basis of current data that has some issues is, well, just wrong.

What's important in the contour map is the contours.  They are relatively close in shape to the Quad contours.  I'd still put my money on the 1913 topo as being a better representation of what was there then.  It was a purpose specific survey conducted at a finer resolution.

 

 

I thought I'd take a shot at demonstrating what is happening with the 1/9 NED data, following Bryan's lead and using Merion's 12th green.

Here is an image of part of the 12th green, and next to it is the corresponding NED rasterized image from the USGS Viewer:



The rasterized image does not look like much, but at this scale we can see the individual tiles.  (According to the Viewer's ruler, each tile measures a bit less that 3x3 meters.) There are 23 tiles across bottom of the image, so I assume 23 data points.  Using the Viewer's elevation function, and clicking at different parts of the various tiles, one can see that each tile represents single, unique elevation.  So by a round-about methodology, I think we are down to single data points.

As for the grayscale scheme, the various shade of gray do NOT seem to represent distinct elevations.  Rather, the shades seem to represent the magnitude of the delta between the data-tile and the neighboring data-tiles.  The darker the shade, the more abrupt the change.   So the abrupt elevation change makes the bunkers look almost black. This is one reason I think it is hard to read close up.]

Here again is the photo image, this time with the rasterized image created with 1/9 NED layered over the top.  We can see how the "data-tiles" (for lack of a better term) line up on the image:

        


Below the image is a column bar chart providing a rough, un-extrapolated, unsmoothed, cross-section of the bottom row of tiles across the bottom of the image.  As you can see, the data-tiles appear to be picking up even relatively small differences in elevation across these 23 data-tiles.  One could fill in all the datapoints and come up with a elevation rendering of the 12x23 data-point area, but that would be rather tedious.  

Here is a closer look at what I believe is the actual raw data represented by each data-tile along the bottom row, from left to right.  I've also included a description of what we see in each data-tile.

310.51  Rough
310.26  Rough
309.55  Rough
307.80  Rough/Bunker Edge
305.13  Bunker Edge/Bunker
303.31  Bunker
305.08  Bunker/Bunker Edge
306.83  Green
306.32  Green
305.72  Green
305.13  Green
304.54  Green
303.91  Green/Bunker Edge
301.17  Bunker Edge/Bunker
298.71  Bunker
298.66  Bunker/Grass Island
298.21  Grass Island
295.92  Grass Island/Bunker
295.76  Bunker/Bunker Edge
295.90  Rough
294.71  Rough
293.53  Rough
292.34  Rough

So we have about a 6 or 7 foot drop from the left rough into the left bunker, then a rise about 3 1/2 feet back up to the green, then a green sloping slightly and smoothly toward the right bunker, then a drop of 8 or nine feet into the right bunker, then not much of a rise out of the bunker on the far right rough, then the ground continuing to slope.    I am not sure if this is exactly what is there in terms of the ft. drop, etc.  I think Jim should be able to confirm that this is pretty much what is happening on the ground, considering that there aren't that many data-tiles relative to the features such as the bunkers.  For example there was only one data-tile each totally in each of the bunkers.  Who knows it if it at the low point for this line.

As importantly, we can see that there isn't necessarily a correlation between the actual data readings and the the Global Viewer's ability (or lack thereof) to created extremely accurate contours depicting relatively small areas with the 1/9 NED.   The accuracy of the actual measures is dependent upon LIDAR technology, and according to the USGS the data readings themselves (what I call the data-tiles) ought to be accurate to within +/- 1 meter.  (I suspect it is more accurate than this, but that is the standard they provide.)

Now all this is just me trying to figure out how the 1/9 NED is depicted on the Viewer.  I could be wrong and am as always open to comments and suggestions.  
______________________________________

ADDED:  So above is how I think it is supposed to work.   The trouble is finding locations on the PV area where it will work.   I think that we can at least find higher resolution areas, but perhaps not as clear as the data for Merion.  But it is difficult to tell what data points are real and what are extrapolations.  It may be a matter of waiting until if/when the USGS supplements this particular data set.

[JESII]

Pat,

If I had pretended the aerial you posted was of the winter and it was from April would you call me "intellectually dishonest"? Or just go straight to "liar".

How do you address Bryan's higher resolution photo that shows the vast majority of the trees on the ridge right of the 6th hole are deciduous? For those readin along...the pine trees that are there are 50 feet below the height of the fairway.

[Patrick_Mucci]

Pat,

If I had pretended the aerial you posted was of the winter and it was from April would you call me "intellectually dishonest"? Or just go straight to "liar".
Jim,

Sorry if my memory of something posted 4 months ago was off by 10 days or so.
Foliage on deciduous trees in Camden County only 10 days or so removed from winter's official end doesn't differ, substantively, from foliage in December, January or February. 

How do you address Bryan's higher resolution photo that shows the vast majority of the trees on the ridge right of the 6th hole are deciduous?


What you fail to understand is that there's no segregation of species when looking from one vantage point to another.
It's the totality of the forestation that obstructs your view.
And as you know, or should know, you don't need many pines to block your view.

For those readin along...the pine trees that are there are 50 feet below the height of the fairway.[color=green

Jim,  again, you're dead wrong.
You're not as familiar with the site as you think you are.
Those trees, the pines, obscure your view from the 6th fairway across the 4th hole to the 2nd green and 3rd tee][/color]

Bryan,

Your statement completely ignores a critical factor, namely that the caption describing the view,  states that it as going across the 4th hole TO the 2nd green and 3rd tee.  As TEPaul has stated in several emails to you and others, your lack of familiarity with Pine Valley and the terrain at Pine Valley is due to the fact that you've never set foot on the property and that lack of familiarity is causing you to draw erroneous conclusions

Would you also look at the huge, dense stand of pines behind the 2nd green, that block ANY view of the 2nd green from the 6th green.
Also note how that stand extends to the left, into the woods near the house, and to the right to the pond, indicating that the ridge line was entirely or predominately pines, preventing any view behind them.. 

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