➕Add a Discussion
➕Add a Blog Post
Find a Surveyor
Join a Hub
|*Apps Open In Window:
Just lookimg for some help on a couple of questions in the elements of a projection
1. what is scale coefficient
2. what is scale error
3. what is grid scale constant
any help would be great
This Content Originally Published by a land surveyor to Land Surveyors United Network
Hey Mate, How is it down under , i like to take a look at that Southern Cross myself. Worked with a Civil Eng / Surveyor from New Zealand ,here in Texas he was a blast told me many things about New Zealand, he told me dinosaurs were only 6000 years old,Like i said he was a blast. Where do you live,i like to hunt those Stag bucks. Anyway here is some more info and this New Zealand site there is a lot of links and information there that can help you i have even used it, plus some more like survenator gave you. so good day mate. stay in touch Mat.
billy, I see you live in Hokitika
1. What is scale coefficient?
In New Zealand, the official datum is New Zealand Geodetic Datum 2000 (NZGD2000), as you can check on DATUM, and the official Projection is New Zealand Transverse Mercator 2000, as you can check on Projection.
UTM projection is a projection system that was designed for sailing, so the angles on the real life and on drawings are the same, but, the distances are not the same. In order to match, it is required to apply a scale coefficient (factor scale) that depend on your coordinates and the coordinates of the target.
2. what is scale error
Scale error is the error that you have when you apply a scale. As our visual accuracy is 0.2 mm, on any drawing, your scale error will be 0.2mm x Scale. For example, in a 1:10000 scale, the error scale is 0.2mm x 10000 = 2000 mm = 2 m. So it is useless any survey with 2 points within 2 meters, as there won´t be any representation for it. For digital purposes, it is the same issue.
Regarding height, it is something similar but regarding level curves. For example, usually, on a 1:10000 scale, the curve levels are within 1 meter, so any element that has less than 1 meter in height won´t have any representation on drawings.
You should consider this issue in order to know the accuracy on drawings. So, for example, if your are doing a survey for a 1:10000 scale drawings, you shouldn´t waste your time take details that have less than 2 meters on plan and less than 1 meter on height. If you take a survey of one road, you shoul take the axis and the end of the paved/unpaved shoulder. The remaining details should be done by CAD systems, as on scale, it doesn´t have representation. The kerbs have no representation, so 1 point is enough for surveying, if one staircase is minor than 2 meters, you shoudn´t represent it...
3. what is grid scale constant
A grid scale constant can be many issues, but usually, it is mention for:
- on UTM (Mercator) projections, it is the grid area when you can consider a factor scale as constant.
- on normal surveying, it is a grid when you are considering the factor scale constant (usually 1.0), so you don´t need to apply factor scale.
Which one do you think are you interested?
Thanks for being a mate David,that's what this is all about helping surveyors of the World.
Hi Charlie, Michael Baker Jr. wanted to send me to that part of the world,but also to Saudi Arabia,South America,and this is when the Alaska Pipeline was being built,they wanted me to go work on it also. So i studied how to do a star shot on the Southern Cross for the South Pole, for New Zealand.I made plans to go and my mother became very sick ,so i change my plans and stayed in the U.S.But that's life.Everyone surveys the same,about their system. they have their own projections for this area the old system was done for sailors.That's why i gave Mat the New Zealand Site,there is a lot of info on this site about New Zealand and there controls,since he is a student i thought this would help him, go there and look at it.I found it about a year ago ,looking for Datum conversion,Back to the hunting they have a special Deer , a Stag similar to North American Elk. these Deer came from Europe, I forgot the date but it real old.they are more impresses than our Elk, much larger and there racks also, in fact this help save this Deer from extinction, but now it become even bigger in New Zealand over the years of living there. I was in hopes i would get to hunt one if i went. So Mat take all this in and know that you have new friends in the Survey World and we are here to help you.
around the 1850 british red deer (Cervus elaphus) were released into New Zealand. They cause some destruction to the native plants in the high country. in the 1930 they culled of 1000 of them. Numbers are getting up there again now and you do see some large stags being brought out. i live on the west coast of the south island where the deer can be found everywhere.
Thanks for all the information and help guys really appreciate it
Thank you Mat, Those are beautiful deer and the Country. that is a nice River where you live. The old Eng./Surveyor I cannot remember his last name,but he taught Surveying in a College in Christchurch.He was on his summer break when he came up here .His son owned a large constructions company and a car wash chain here in the U.S. his son just wanted him to be there on this site as a observer, Berry was his name,He told me i was the most important man on the job.He told me a lot about surveying down there,it made me wish i could have went and seen your country.As science as he was, he believed earth was only a few thousand years old,do not get me wrong he was a very smart man,but talking to him, and his wife you felted they were very old British .Anyway i never got to shoot your South Star are see the Southern Cross or kill a Stag.So learn how to take a Star or Sun Shot for me one day, you will never forget the feeling of doing this. if you need any help with anything ,i will help were i can. Stay in touch.
I think you are right what you say meanings of words & therefore the definitions seem to vary somewhat with the locality. A lot of definitions of projection elements or surveying practices i have researched for my studies definately have more than one definition, and some even contradict each other.
Like everything on the internet you dont know what to believe sometime.
Thanks for your replies