If we're doing contours, we do everything.
> Perhaps you need to review the definition of "topography". ALL topograhy is contoured. Elevated, man -made features are generally not called "topography".
Definition or regional use of a word?
In definitions, I see many references to "man-made" features.
:good:
Christ has a great example. That crown in the road really shows up nicely.
Exactly!
Actually, we only contour the easy surfaces. the hard surfaces, we just fake the contours. We will usually put some big jags in them to make them more realistic.
Perhaps I have received bad training, but in this country (not USA) every topo I have seen does not have contours on the roads, concrete etc. Needless to say I will put them on everything from now on.
I am here to improve both myself and surveys. Thanks to all the useful non-judgemental comments. To the other 2 I should have known better from previous posts I have seen and chosen my words more carefully, I hope it wont deter others potential posters.
Contour everything, and if they want it into Revit, then you may have to look at giving them a file with just the contours on a very tight interval. (eg, 2cm contours).
Revit is pretty basic at bringing in topo.
:good:
good and interesting post.
one more question, do you mind sharing your country?
Christof.
No sir, that's the way YOU interpret it. Yes, man-made features are shown on topographic maps, but they are called "plannimetric features" and are not part of the topographic surface depicted on the map. The topographic features are the elevations and contours depicted thereon.
I have been a cartographic drafter since 1968 and have drawn topographic maps of areas from the Middle East to Viet Nam, Thailand, Cambodia, Puerto Rico and all across the United States. Every thing from 15' quads, 7.5' quads, JOG Charts, aeronautical maps all the way down to local site surveys.In all of those maps for many different agencies, what I have stated here is the rule and the norm in the map making profession. Just because some rookie surveyor cannot understand those concepts will not change the way a topographic site survey will be performed.
I appreciate your input and will take it all onboard. I would just say that I am doing things the way I learned from a previous employer and viewing other peoples drawings here. Perhaps it is just the way it is done here (even if that is wrong). If you feel the need to insult me because of that then I don't know....
I am sure you did not wake up one morning and know everything. I personally find that I learn new things each day and I constantly aim to improve my work.
Perhaps this thread is an example of why many lurk rather than post.
keep in mind that the message board comments can sometimes be misinterpreted. (My wise-asss comment about contouring easy surfaces was an attempt at humor.)
Also, most of my contouring is for engineering plans or for surveys where the planning board mandates contours. For engineering plans, the hard-surface grades are often important. For mandated contours by planning boards, the requirements simply specify that contours are required and do not specifically state that hard surfaces are exempt.
One minor clarification to my post about contouring everything: We do NOT show contours inside of existing buildings.
Agreed, inside buildings.
However, sometimes jobs come up where there is argument regarding the flatness or otherwise of floors. In these cases we would use a contour interval appropriate to the tolerance allowed on the floor, perhaps 10, 5 or even 2mm. intervals.
If you ever get one of these you need to try and picture the DTM triangles laid out on the floor as you survey, otherwise you get sharp jaggies everywhere. Single points on high or low spots are not good - three or four around each apex help to smooth the contour lines. (This applies also to normal topo). That way the contours flow and give a much better image of what the surface really looks like.
You mentioned top and bottom of road kerbs earlier - we would normally delete the triangles out between the two strings, otherwise it just fills in solid.
I make my topography drawings so that the contours close on themselves or start on one side and can be traced without breaks across and out of the area of interest. Where the improvement locations is the only reason for being there, that a site plane y my defination, it shows improvement in relation to boundary's or some other stable feature. The topog drawing will show man made surfaces and associated contours, but not to the detail of a site plan. Have noticed that definitions of terms across the nation is not uniform.
jud
I appreciate your input and will take it all onboard. I would just say that I am doing things the way I learned from a previous employer and viewing other peoples drawings here. Perhaps it is just the way it is done here (even if that is wrong). If you feel the need to insult me because of that then I don't know....
I am sure you did not wake up one morning and know everything. I personally find that I learn new things each day and I constantly aim to improve my work.
No, I did not wake up one morning and know it all. As I stated previously, it has taken me 44 years, to this point, to know my craft as well as I now do.
The insult was you basically telling me that I did not know what I was talking about. I have tried to explain the details that you are over looking in order to educate and enlighten you. If you find that insulting, so be it.
MANY surveyors draw contours. MOST cartographers look at them , grin and shake their heads. Close enough I guess.
There's usually a whole lot more to it than most surveyors know about. That's why engineering firms hire people like me, especially now with generating tins and surfaces. Vertical faces are often over looked. They can be 6" tall or 60 feet tall, but they must be properly reflected in the surface tin. If your contours shoot straight across the curb lines, you have a surface error that will make an engineer weep. It's all part of the battle betewwn engineers, architects and surveyors and I am caught in the middle of it all.
I use Break Lines for such things and are a strong believer in the one doing the drafting or it's approval needs to be the one on the rod, contrary to some, the rod is the smart end, a well programed robot can run the gun.
jud.
jud
Okay thanks for the input. I aim to perfect what I am doing, that's why I posted here. If you can recommend any reading/resources on the problems encountered that you mention I would be interested. Just to clarify I create a tin model for the entire surface of every site, it's just the contours I was refering too. I also take care with the things you mention when it comes to the tin.
I am an old tyme Army map maker, so most of my reference material is from that source. Those manuals are the basis for most mapping standards anyway.
I would recommend getting a copy of the NSPS Topographic Mapping Standards available for download on the NSPS web site.
Then I would download a copy of the Corps of Engineers manual- EM-1110-1-1005 Topographic Surveying and the U.S. Army FM-3-34.331 Topographic Surveying.
If you have any problems downloading these files email me and I will burn you a CD of these manuals and a few others that I have.
These manuals outline field procedures, but give a lot of insight into what the data represents and how to depict it.
You can capitalize the word "you" all you want, but there is no need to interpret a definition. They are usually pretty well stated -
Definition of TOPOGRAPHY
1
a : the art or practice of graphic delineation in detail usually on maps or charts of natural and man-made features of a place or region especially in a way to show their relative positions and elevations
b : topographical surveying
2
a : the configuration of a surface including its relief and the position of its natural and man-made features
b : the physical or natural features of an object or entity and their structural relationships
Merriam-Webster Online Dictionary
Now it does say "especially in a way to show their relative positions and elevations". However, it does not say "exclusively to show their elevations".
Further, by looking at the etymology of the word, there is inclusion of man made features - even so far as including local history. How on earth would you plan to place contours on local history?
About 20 years ago, I was also arrogant enough as to believe my way of thinking was the only acceptable way. A very intelligent gentleman I worked for sent me out to do a "topo" of a site. It turned out he did not want contours. Naturally I was so brilliant I pointed out "THAT is not a topographic survey". I distinctly remember pointing out "THAT is a planimetric survey". If I was as smart as I thought I was, I might have realized that the definition does not make exclusion of a planimetric drawing.
As you state, "In all of those maps for many different agencies, what I have stated here is the rule and the norm in the map making profession." So within those many agencies, the working definition of topography is what you say. Instead of smarting off to the guy about reviewing a definition, you could as easily point out that in most mapping agencies the accepted idea is.... However, that does not change the actual definition for everyone in every area of the world. That is like saying because surveyors refer to a drawing of a property as a "plat" means that the definition of plat as an actual parcel of land is no longer valid.