My grandfather on my mother's side was a land grading contractor. He used horse drawn equipment. His son (my uncle) was also in the same business but he used modern heavy equipment. The Huber-Warco grader had hydraulic controls, most of which had been welded because the "cat skinners" that he hired were trained on the Caterpillar version that had mechanical dog clutches and if you didn't hit them hard you might get a broken wrist. His Euclid bucket (Wiki) had an engine in front and another engine in the back. His competition was using CAT scrapers and a bulldozer to push the scraper. That means his competition had to hire two heavy equipment operators and my uncle only hired Sid. Both very modern machines for the early 1960's.
I have my grandfather's level & tripod. It only has a scope and level bubble attached to the scope. Not angle readouts.
My uncle had a good "eye for level". He also carried a hand level and a yard long lath with a notch for the hand level on various tractors.
I use the method called Stadia to determine both the distance and elevation from the instrument to the rod.
An <shift><click to download> Excel spreadsheet does the math. The Example Spreadsheet has an explanation of how to use it.
I got my own Leitz 115A transit.
I tried using the Bushnell golfing range finding binoculars, but they only have 1 yard resolution and I am trying to get to ideally inches, but practically to feet of accuracy, so they don't work well.
Stadia is part of Plane Table mapping using an alidade. See M1913 Sketch Set.
POB magazine - Plane Table Mapping -
A gyroscope will precess and this can be used to determine true North. It finds use in underground locations where you can not sight the North star Polaris or the Sun.
See my Sensors page North Finding for more on this.
The government version is called the AG8 and is covered in TM 5-6675-250-10
The theodolite is the T16 and is marked:
p/o (part of) GG3-1 North Seeking Gyroscope
p/n 560 247
By sighting the Sun or North star you can determine the direction of true North very accurately. To use this method you need to know either where the Sun is or know where the North star is. That is why the Ephemeris data is required. Without it you can get to within a degree or so, but with it you can get to seconds of angle.
the Advantages of Polaris Observations in Land Surveying - Night or DAY
US5537201: Electronic leveling system, electronic leveling apparatus and leveling staff by TOPCON DL-100 Series Digital Levels - Article in Prof Surveyor - June 99
The rod has a special pattern that can be read by the level. The height and distance to the rod can be automatically calculated. The rod may have correction for tilt and temperature. Topcon does not really tell you what their equipment can do, maybe all surveyors already know.
Tripod Data Systems, Inc. -
Chris Nail - some programs for download
Apex Data Collection Software - 30 free trial
J.S. Sprott Programs -
HPcalc.org - programs for a lot of applications
CalcPro - many bugs on new web pages
Quickclose - Uploadable and editable ASCII HP48 programs -
Radius (Wiki) : 6,371 kilometers (3,959 mi)
Figure of the Earth (Wiki)
Polar motion (Wiki)
The eBay listings for survey instruments typically have very wrong titles. Here is what I think these things are:
- Level - has a scope and bubble level, used to establish level and grade, some may have a calibrated horizontal circle for bearing.Most are tripod mounted but some are handheld.
- Alidade - a scope designed to sit on a table rather than directly on a tripod. Used to make maps to scale directly in the field.
- Transit - has both horizontal and vertical scales that traverse 360 degrees so the scope can be "plunged", i.e. used upside down thus canceling some common alignment errors when turning angles. Both the vertical and horizontal scales have a reference mark that can rotate about it's axis and a scale that can rotate relative to the reference. So you can set the scale so it reads zero and then rotate both of them so that the first target is on the cross hairs. You then lock the reference. Now unlock the scale and turn the transit to the second target and after aligning the cross hair lock the scale. You can now read the angle. You can now unlock the reference (the scale is locked to the reference) and turn back to the target and lock the reference. The scale reading at this point is the angle between target 1 and target 2. Now unlock the scale and again turn to and align on target 2 and lock the scale. Now the scale reads twice the angle between target 1 and 2. Now plunge the transit, i.e. turn the scope upside down, release the reference and turn the scope so it's aimed at target 1 and lock the reference. Now unlock the scale and turn from 1 and align on 2 and lock the scale. Unlock the reference and turn back onto 1 and lock the reference. Now unlock the reference and align on 2 and lock the scale. The scale now reads 4 times the 1 to 2 angle and you have canceled some of the instrument errors by turning half the time with the scope normal and half the time with the scope inverted or plunged.
By making multiple measurements you can get more accuracy and precision. Maybe you can only read the vernier to one minute of arc, but after 3 normal turns and 3 plunged turns the angle is now calculated to the nearest 10 seconds. Starting with a 30 second transit and making 6 turns your at 5 seconds, etc. Probably does not do too much good to make 12 turns since other errors probably will show up. If the overall instrument was that good they would have put a better vernier on it and sold it for much more money.
- Theodolite - similar to a transit except instead of using a vernier to read the horizontal and vertical scales, glass disks and an optical magnification system are used to achieve much more precision. Newer models also have a digital display and output to a data logger.
- EDM - Electronic Distance Measuring - Uses a pulse of IR light to measure the distance to a retro reflecting prism very accurately.
- Total Station - combines a theodolite and EDM into a single instrument with digital output to a data logger. A semi-total station has the built in EDM and probably has digital readouts, but does NOT have digital download to a data logger.
- Non Cooperative Total Station - a total station that does not need prisms. It can read the distance to most objects directly.
- modern tripods use a 5/8 x 11male thread, older tripods us a 3½" x 8male thread. Instruments have a female thread.
Heliotrope - Uses mirrors to send the Sun's rays to a far away surveyor so he can take a reading on the location of the Heliotrope. Photo from Transits of Venus - another heliotrope
From: Transits of Venus
Illustration from The principles and Practice of Surveying Vol II
The "telescope" on the back does not have an eyepiece, but instead has some white material that reflects the sun back. This causes a reflection on the clear glass center spot and when that image of the sun is pointing to the target, the sun is reflecting at the target.
This is very similar to the way a survival/rescue mirror works.
On heliographs one way of doing this is to have both sides of the mirror silvered. Then when your eye seen the sun's image on your face or clothing centered on the hole that allowed the sun's light to make the image, you are looking at where the sun will be reflected at a great distance. This method is as accurate as the front mirror is parallel to the rear mirror.
A mirror that turns to de-spin the Earth and send the Sun's light to some fixed point.Wild T4 Theodolite
I think this is the most accurate of all the surveying instruments. (they go for about $35,000 used on eBay)
http://www.1381st-gss.freeservers.com/ <- survey squadron
http://www.1370th.org/gsshistory/gsshistory.htm <- survey squadroni
- T. F. Randolph Level & Tripod -
- Leitz 215A transit (now Sokkia 7327-60), Tripod and extension rod
- K&E 76 0000 Alidade
- K&E Leroy Lettering Set
Most of the lettering on drawings, prior to Computer Aided Drafting, was done either by hand or using a Leroy lettering set.
- M1913 Sketch Set -
- M2 Compass and others on Navigation web page.
Army compass with 0 to 6400 mils instead of 0 to 360 degrees. One mil is 1 yard at 1000 yards to make artillery spotting easier.
The technical manual is TM 9-1290-333-15. on line at: https://www.logsa.army.mil/etms/data/A/027327.pdf - this is a secure server that REQUIRES the 128 bit version of Netscape. The US patent 1,571,697 for this compass was assigned to K&E.
FSN from the TM is 1290-946-8757.
There are a number of "Brass" compasses being offered on eBay that are imports and come in a number of different sizes, but all have the appearance of this design.
- Marching Compass
- Range Finders - Stadimeter, Laser, Optical, etc.
- Theodolites N010C (10C) , NT2S, Wild T2, Wild T16
- K & E hand level made without optics
- O. J. Kuker patent # 1741422 Hand Level Dec 21, 1929 356/249
- Field Range Finder by Edumd Scientific Co.
- Wallace & Tiernan FA 181 Altimeter - made for topological map surveying
- Abrams Universal Sun Compass SC-1 -
- Level Vial, Frankford Ordnance Depot, p/n: F209 0431900 dwg: B173123 May 1952
If you know where this level vial is used please let me know.
Got this after studying the M-132 Signal Lamp. The M-132 is a mystery since it has a lot of features that do not make sense on a Morse Code signal lamp, but do make sense on a survey instrument. This Survey Signal Lamp has very similar features, i.e. a peep sight, up-down tilt mechanism, azimuth pointing by rotating about the mounting screw (either 1/4-20 or 5/8-11)
|Light, Signal, Survey, 1 In, Diameter
Reflector, Battery pwd., w/case size 1
FSN 6675-641-3536 (FSN 6675-641-3569 is for a Wallace & Tinnerman altimeter)
Stewart-Thomas Industries, Inc.
Contract DSA 700-69-C-G140
Serial No. xxx Del'd 1970
Looks like New Old Stock (NOS). There is no serial number
on the label. The lamp bags contain both PR2 and PR9
Flange type flashlight bulbs. The PR2 is brighter and does
not last as long as the PR9.
PR2: 2.38 Volt - 0.50 Amp - B-3-1/2 Single Contact Miniature Flanged Base (P13.5S) - C-2R Filament Design - 0.80 MSCP. - 15 Average Rated Hours - 1.25" Maximum Overall Length - 0.45" Maximum Overall Diameter - Typically found in flashlights using two "D" cell batteries.
PR9: Standard replacement
flashlight bulb - 2.70 Volt - 0.15 Amp - B-3-1/2 Single
Contact Miniature Flanged Base (P13.5S) - C-2R Filament Design
- 0.25 MSCP. - 45 Average Rated Hours - 1.25" Maximum Overall
Length - 0.45" Maximum Overall Diameter - Typically found in
flashlights using two "D" cell batteries.
Power can be supplies via field wire
using the push down terminals or by a cord with phone tips.
There is a knob on the back that tilts the lamp head up or down. Azimuth aiming by rotating about the mounting screw.
It occured to me that this would be an excellent way to mount the RA-2 GPS antenna using the magnetic feet on the antenna. This is because the Signal Lamp has both 1/4-20 and 5/8-11 threads. BUT . . . the sheet metal is aluminum so it does not work.
In high school I took all the drafting classes that were offered. Later that became important since it was a prerequisit to taking a Physics class at Foothill College that allowed me to get an AA degree in 1962, then a BSEE in 1964 and MSEE in 1965. Without the drafting class those dates would have moved back a semester or year.
The Planimeter (Wiki) is a drafting tool used to measure an area by tracing out it's outline. The early models are analog computers.
2768785 Planimeter, Ernest W Silvertooth, Librascope , 1956-10-30, -
Pentax - total stations, etc.
Leica - total stations, etc.
Sokkia - total stations, etc.
Cyra - 3D laser scanner $155,000
Nikon - total stations, etc.
Spectra Precision - total stations, etc.
Topcon - total stations, etc.
Trimble - GPS but also total stations
Ref 1. YouTube: How do trig points actually work?, 15:03 -
1. Error caused by thickness of metal strap inserted into trig pillar side plate.
2. Error when using mag compass to take bearing since no declination correction. Much better to measure angles T1 to Tn and T2 to Tn.