h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

>>Simple to make and easy to carry the groma possibly from gonmon^ meaning indicator in Greek, or as it is some times known the surveyor's cross was the most widely used Roman surveying tool.<<

Simple to make and easy to carry, the groma^, or, as it is sometimes known, the surveyor's cross, was the most widely used Roman surveying tool.


^Possibly from gonmon, meaning indicator in Greek, which was originally a tool used to locate North without the aid of a compass.

____________________________________________________________________________
italicize: gonmon, surveyor's cross, gonmon, and indicator ....i can't here
^ takes the place of footnote number

fluffykerfuffle

All doone thank you

ahhhhh it does move across the mind's eye nicely doesn't it! ...onward!

aaaaargh this one was haaaaaard... WE NEED A PICTURE !!! http://images.google.com/images?hl=en&q=groma&btnG=Search+Images&gbv=2 perhaps Traveller in Time U228046 can put in the one you select? or help you figure out how to make it appear on this entry page?

aaaaand... this is just a rough draft.. it is easier to follow but im not sure if i got the meaning right... tweak it all you like



Construction

>>The Upright; It was a pole metal tipped for pushing into the ground, the height of the upright was about one and a half to two meters. <<
The Upright - a one and a half to two meter pole of which one end was metal tipped to facilitate pushing it into the ground.


>>The Rostro; At the top it was fitted with an with an extension called the rostro. This was fixed at one end and rotated through 360 degrees. There was a plumb line fixed to the end of the rostro beneath the mounting point for the next piece. This allowed the rostro to be adjusted in the vertical plane against the upright, causing the mounting swivel for the groma to be horizontal and act as a third sighting point. <<

The Rostro - an upwardly curving extension, the horizontal end fixed to the top of the upright via a swivel mount. This extension rotated horizontally through 360 degrees. The center point of the groma was attached horizontally to the upper, vertical, end of this extension via a swivel mounting, and a plumb line was fixed beneath the groma's mounting point.


>>The Groma; Was a simple cross of wood with arms of equal size with four plumb lines, of equal length, suspended from the end of each arm.<<
The Groma - a simple cross of wood with arms of equal length, each in turn having a plumb line suspended from the end of it, each of which was equal in length to the other three plumb lines.


>>The Marker Peg; Was a peg positioned in the ground below the plumb line fixed to the end of the rostro to mark the datum point.<<
The Marker Peg - a peg positioned in the ground below the groma-mounting plumb line to mark the datum point.

>>This allowed the rostro to be adjusted in the vertical plane against the upright, causing the mounting swivel for the groma to be horizontal and act as a third sighting point.<<

and.... this i didnt understand so i left it out ...maybe you can fix it up and put it where you think it goes ...maybe it belongs in the how it works part of the entry.... i will look to see if it works better down there.

also, i think the operative word for the adjustment in the vertical plane thingamabog is "trued"
...like vertically trued ...not sure tho.... its a carpenter's or builder's term. i suppose i could google it.... unless of course you already know... hehe
....anyway... if that IS so... then how about this?

This arrangement vertically trued the rostro, which in turn caused the groma to be horizontally trued . (or 'plumbed' for 'trued')

or

Suspending a plumb line from the groma-mounting allowed the rostro to be vertically trued, thusly resulting in the horizontal trueing of the groma.

heres the last installment:


How It Worked

>>When the groma was set up, generally on a high point or rise in the ground the surveyor would turn the groma (the cross) so one of the arms pointed in the direction the that the road (or whatever) was to take. The surveyor would send out an assistant with some ranging poles, the assistant would stop after about 125 paces and hold up a pole. The assistant was directed until he was line with the three strings of the groma. The two on opposite arms of the cross (North and South) and the plumb line fixed to the end of the rostro. The process was repeated until the assistant had run out of poles, leaving a straight line of poles marking the course of the road. The surveyor would then move on to the last pole, set up the groma again and send out his assistant with ranging poles to repeat the procedure.
If laying out a 90 degree right angle or corner of a building the East and West plumb lines would be used.<<

When the groma was set up, generally on a high point or rise in the ground, the surveyor would turn the groma (the cross) so that one of the arms pointed in the direction that the road or construction was to take. The surveyor would send out an assistant with some ranging poles; the assistant would stop after about 125 paces and hold a pole vertically, one end on the ground. The assistant was directed to move until the surveyor could see that the pole was in line with the three strings of the groma: the two on opposite arms of the cross (North and South) and the plumb line fixed to the groma end of the rostro. The process was repeated until the assistant had run out of poles, leaving a straight line of poles marking the course of the road. The surveyor would then move forward to the last pole, set up the groma again and send out his assistant with ranging poles to repeat the procedure. If laying out a 90 degree right-angle or corner of a building, the groma's East and West plumb lines would be used.

Who Used The Groma

>>Gromatici; who were general surveyors.<<
Gromatici - general surveyors. keep the italics for gromatici and agrimensores.

>>Agrimensores; who were land-surveyors.<<
Agrimensores - land-surveyors.


>>There were four main specialist types of Roman surveying<<
There were four main specialist types of Roman surveyors: keep the italics for military, agricultural, architectural, and services,

>>Military; These were the men who laid out the roads throughout the empire, the were also responsible for surveying the sites of Marching, Camps, Forts and fortifications these men also laid out the coarse of Hadrian’s wall and the Antoine wall.<<

Military surveyors laid out the roads throughout the empire. They were also responsible for surveying the sites of (for?) Marching, Camps, Forts and Fortifications. These men also laid out the courses of Hadrian’s wall and the Antoine wall.?


>>Agricultural; These men were employed to supervise the allocation of farmland in the new the colony’s or supervise the distribution of lands around the town in which he was based. Early Roman field systems were noted for their square or rectangular shape <<

Agricultural surveyors were employed to supervise the allocation of farmland in the new colonies and to supervise the distribution of lands around the town in which the suveyors were based. Because of the groma, it is no wonder that early Roman field systems were noted for their square or rectangular shape.


>>Architectural; These surveyors laid out the municipal buildings and streets of the towns and cities.<<
Architectural surveyors laid out the municipal buildings and streets of the towns and cities. ?


>>Services; Often working with architectural surveyors, responsible for works such as water supply, and would be controlled by the appropriate urban surveyor.<<

Services surveyors, often working with architectural surveyors, were responsible for works such as water supply, and were controlled by the appropriate urban surveyor.


Surveying With A Groma
(either keep this subheading as is and add surveying info on buildings, urban streets and layout of rural land parcels.... or change it to 'Surveying Roads With a Groma' ) ?

>>The roads were surveyed in the same way all through the Roman world, it was impossible to lay out a perfectly straight road over many miles using the groma, this explains the course corrections (slight bends) that occur every few miles. ?Groups of surveyors were used when a road was built between two points. ?First the route was surveyed in sections marking out the high points. ?After the first stage had been completed the route was surveyed again between the high points to make it as straight as possible.

The roads were surveyed in the same way all throughout the Roman world. It was impossible to lay out a perfectly straight road over many miles using the groma. This explains the course corrections (slight bends) that occur every few miles. Groups of surveyors were used when a road was built between two distant points. First, the route was surveyed in sections marking out the high points. Then, after the first stage had been completed, the route was surveyed again between the high points to make it as straight as possible.

Hi Fluffy K

Thanks for the work. All done please comment.

yay

looked it over... pretty clear now... especially the "...to act as a third sighting point." addition!

thanks, i enjoyed doing this feel free to call on me for proofreading anytime


and no, i don't mind you asking where i am

So where are you.

By the way brilliant job on thr proof reading. well done

heh thanks it was fun!

um have you seen a little nametag around here... has "fluffykerfuffle who is now learning more things" on it... i seem to have misplaced it

. .. . .. . . ....silly walks over to your stack of notes, forefingers caught in a chinese finger puzzle. ... .. ..

um forgive my inability to look under these... i seem to be digitally incapacitated at the moment. could you look through those to see if it is there?

No sorry not here can I help you fix it or get you a new one.

. .. .. . ...the unbenametagged, chinese-finger-puzzle-entrapped fluffy kerfuffle smiles bravely. ... . . ... .





thank you. for the nonce i will keep looking but shall return if i canna find it....

incidently, there is a roman gladiator in The Asylum right now F7062353?thread=4054788&skip=60&show=0
might be interesting for a future topic... you maybe could interview him

Hi Any more comments please...