[TEPaul]

I was just analyzing the beautiful aerial photograph of Pine Valley shot by Maynard Clark in 1953 that appeared in a feature article in HOLIDAY magazine about PV by Herbert Warren Wind.

It is a beautiful aerial pretty much over the top of the course and showing the whole course which means the photographer was probably up there about 5,000 feet.

You can see everything on the course. The only real problem is it looks like it was probably shot about 4-4:30 pm and due to that it is very misleading when one tries to analyze the tree positioning along the western sides of the holes.

For instance, the group of trees that sit up on the little knoll that creates the back of the right tee on #13 casts a shadow right across the entire middle of the 12th green. From that height it is very hard to decipher where the actual trees end and their west to east shadows begin.

Aerial photography ain't cheap---we did a bunch of it for GMGC a few years ago so if you're going to spend the money to do it try to get the aerial photographer to get some right over the top of the course and to shoot 'em at high noon.

When people try to analyze things like trees on the course and where they begin and end in the future they will thank you for thinking of the time of the day and the sun's position.

[Ally Mcintosh]

I wish someone had thought about taking decent aerial photos of Irish courses.... I've been trawling through some archives and can only find decent photos of Baltray and Portmarnock...

Will keep looking... Its the old ones I need

[Craig Disher]

Tom,
Nice thoughts but I think you're mistaken

The absolute best time to take aerial photographs is on a clear mid January day at 3:30 in the afternoon. There's no smog, leaves are off the trees, and the long shadows show the ground contours. Pine trees are a problem but they tend to disperse sunlight, not block it entirely.

[Dave_Miller]

   
 shoot 'em at high noon.

When people try to analyze things like trees on the course and where they begin and end in the future they will thank you for thinking of the time of the day and the sun's position.

Tommy:
Maybe that's what we should do to anyone who tries to change the great Classic Courses.
Best
Dave

[Kalen Braley]

Tom,
Nice thoughts but I think you're mistaken

The absolute best time to take aerial photographs is on a clear mid January day at 3:30 in the afternoon. There's no smog, leaves are off the trees, and the long shadows show the ground contours. Pine trees are a problem but they tend to disperse sunlight, not block it entirely.

What if there's snow on the ground?  Craig: then when?  What's second best?

Shiv,

Thats too easy....do it the day before that clear mid-January day.  Duh!!   

[Craig Disher]

What if there's snow on the ground?  Craig: then when?  What's second best?

I should have seen that coming. A simple answer is that if there's snow on the ground, don't fly. The aerial photography companies that flew the Dept of Ag. missions during the 30s seemed to avoid snow. Of the thousands of photos taken in the NE or upper mid-west (mostly shot in the winter or late fall, btw) that I've seen, none show any snow at all. I assume snow-avoidance was the policy.

[BCrosby]

Craig -

I have some 1938 aerials of Athens CC taken by the US War Dept. at about 3:30 in the afternoon in January.

Problem is the pine trees. They shade two or three greens that have been changed but for which there is no record as to how they looked originally. The aerial is the only evidence we have of what the course looked like at the time.

Are there any technologies that allows you to tease out visual information from the shaded areas in those old photos? Or can you only do that with high res digital pics?

Bob

[Craig Disher]

Bob,
Are you sure the aerials are from the War Dept? The collection of War Dept photos at the Archives begins in 1940. Generally they are high quality with very good resolution. The Dept. of Ag. aerials date from the mid-30s, most were taken in 1938-1940, and they tend to have less clarity since they are mostly at 1:20000 scale. I've seen War Dept aerials at 1:5000 and they show substantial detail. Are there any identifying numbers or letters on your aerial?

I looked for a 1930s aerial of Athens a while ago but all of the Georgia aerials taken by the Dept of Ag. had been converted from 9"x9" negatives to 70mm film.  The detail necessary to see the golf course was gone. If the original 9x9 negatives exist anywhere, it would be good to know.

As for seeing through the tree shadows, the War Dept aerials that have the best resolution do allow that. I have aerials of Misquamicut GC that were so good that the tree shadows actually helped show the green and fairway contours. But if the scale is 1:20000, there just isn't enough resolution in the photo to see the necessary shades of gray. Manipulating the pixels by adjusting contrast fiddling with the gray scale does help but doing that also can be misleading if you don't know what you're looking for.

[TEPaul]

Craig:

Good point you make about highlighting ground contours and such with shadow but I just think the distortion of real pm aerial photographs in the leafy season is so distorting for future observers when it comes to trees. The 1953 PV aerial is a good example.

[BCrosby]

Craig -

My Athens pics are dated '38. I had thought they were War Dept photos. Sounds like they are, as you suggest, by the US Ag. Dept. Their resolution is not very good, which also fits.

Were the higher res. War Dept pics in the early 40's taken of the entire US?

If so, can I assume they are accessible through the US Archives in DC?

Bob

[TEPaul]

Craig:

Weren't the so-called War Dept aerials taken in the 1950s?

[Craig Disher]

The War Dept aerials are a mixed bag of direct overhead photos and oblique panoramas. The earliest ones that I've seen at NARA were taken in 1940. The collection runs into the 1960s but the geographic breadth drops off after WWII.

The early military aerials show strategic areas, ports, coastal regions, military bases, industrial sites; the later ones generally just show military bases. For example, the Dept of Ag. ignored urban sites - like NYC - while the military conducted many aerial surveys of the city and inner suburbs.  They are a very rich source given the high quality of the photos and that they often fill in areas that the Dept of Ag didn't survey.

Unfortunately for researchers, the War Dept aerials are only available at NARA (as far as I can tell). The Dept of Ag. photos were taken by commercial aerial photography companies and copies of the photos have been saved by many local and state governments. In the case of Bob's aerial of Athens CC, the photo may have come from local sources. It didn't come from NARA - the negative of the gc is so small that the course would be almost invisible on a photo.

[Davis Wildman]

Generally speaking, shadows, whether caused by pine trees or hardwoods with leaves off, in the winter, are a result of sun angle and/or site aspect.  The sun is low on the horizon during the winter, even at 'high noon' and will produce shadow and more the further north, i.e. in higher latitudes, and conversely if moving south of the equator.

Photogrammetry is a great tool for generating orthophotos (aerial photos with error and distortion removed-process called orthorectification, such that linear distances and areas/acreage can be determined). 

TEPaul is correct; you can spend a bunch on it and the cost increases as you decrease the contour interval.  2 foots cost less than 1 foots and both are less than 1/2 foot intervals. 

In most cases with photogrammetry you still do not have what you need to accurately determine cut/fill (within about 10% of ground based survey) or in the case of greens' surface restoration, it is not near accurate enough to use in design analysis/rebuild; although it seems fairly common in the golf industry to see even USGS topo used for site planning and construction specification/bidding, which in some cases might be ok, unlimited budget.  They are very dated; best to get it flown for planning needs, and then do site/area specific topo with 3d laser scanner/rtk gps...especially for greens' surface terrain modeling.   

National Map Accuracy Standards (NMAS) spec's regarding ground vertical accuracy says photogrammetry only produces values that are roughly +/- half the stated contour interval.  So, if you pay for 1' intervals, your elevational accuracy contains one foot(!1) of vertical variance and that is a lot of undetermined earth volume across a site of hundreds of acres.  It can be cause for dispute b/t the earth moving contractor and owner's rep.

If snow is on the ground, then ask your fly-guys to stay on the ground...generally they won't fly because they know the photogrammety process will be degraded.

Ok...I don't mean to be such a tech-weeny...hope this helps.

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