Site plans in Autocad or not?

[vbp6us]

Hi,

im new to the forums. I was wondering how people make such descriptive site plans? Does the engineer really draw every single line with that much accuracy? How does he/she know where rocks and trees lie?

What are some addons to Autocad that help in the siteplan making process? I would greatly appreciate any replies.


Thank you.

 

[10Gallen]

It really depends on the level of detail the surveyor can provide to you. Then having a nice library of blocks you can produce something even an Architect will use .
For civil applications however, my tendancy is to simple line drawings, no hatching etc, as the earthworks contractors I deal with "just wanna know what they need to know".
cheers,
GAllen

 

[vbp6us]

Hi,

Thanks for the swift reply. So your saying you make your siteplans by actually drawing the lines? What if the case is more complex or your at a further stage which requires great detail? Then how would you do it?

How and where do you get the info of the lot? I know aerial photoimaging is one way. What are other ways? Using Optical levels?

Thank you

 

[10Gallen]

Well, if you can wear the cost the surveyor can pick up absolutely everything, down to tree species if required. If the pickup is done using a flash total station which can log feature codes, you can download this data to a package (I'm using 12d) with a library of symbols and linetypes to match the survey field codes. The design package will also produce contours. A bit of tarting up in the drafting package to add hatching etc.
But basically, unless you're going to overlay your design on a photo image, say as for new roadworks requiring public comment, you have to collect the data somehow.
A few years ago I worked with a small firm that used photography and surveyed bench marks to create a 3d real space model of project areas - including light poles, bldg frontages, absolutely everything you could see in the frames - but the time & cost was impossible to justify on everyday jobs.
cheers

 

[vbp6us]

Hi Gallen,

Thank you very much for your informative replies!

Do you mind explaining what the 12D is and what exactly I would need to do in this made up situation which is similar to what im in right now:

I buy a piece of land. I need a site plan with the elevations for the ground. I can go with the following options:

a) Using existing real life aerial photo of the lot and place as many symbols as possible.

b) Do what you do, download the information

c) Get a surveyor to do the job.

Is that a fairly accurate assesment? How would I get the elevations of the land if there is no existing data for this land? If the city does not have any records for it, whats my best bet?

What are GIS photos? Ive heard there are GIS satellite photos of just about everywhere in the US. Is this true? These photos give the proper elevations and some even go into the physical features like rocks, trees and other land features.

Would you be kind enough to point me in the right direction(the easiest, if possible) way to make a basic site plan with elevations?

Thank you very much.

 

[10Gallen]

If it's just a lot survey, perhaps you & mate can trundle around with a dumpy level. This will allow you to pick up all the bits of info of note, and you can contour the site relative to, say, the road.
I can't imagine a surveyor would charge a lot for this work either, as it's not likely to require exacting tolerances.
12d is a civil design package, like Terramodel, GeoPak et al. It's an Australian product (plug!), and like most out there has a downloadable trial version.
So unfortunately, for the scope of work you describe, you'll have to draw most of it by "hand". A lot of small businesses (architectural, consulting) tout their wares on the net, with samples of their work you can get an idea of the range of graphics used.
Good luck!

 

[TerryScan]

vbp6us-

I believe option "c" is what you should do.

I do not mean to offend you. It is obvious from what you have said, that you are not familiar with the process of producing a site plan. This is when it is best to hire a proffessional.

Depending on the reason you "need a siteplan" it may be required by code that a proffessional produce the site plan.

Autocad is a drafting/design tool. Just like Wordperfect is a word processor. Wordperfect does not give one source of material nor ability to write.

Although computers are used today as tools to produce site plans, the fundamentals behind creating a site plan have changed little since the notion of site plans was concieved. These are survey and engineering fundamentals. We just have more sophisticated tools to survey, analyze and present the poduct today.

 

[vbp6us]

No offense taken.

I guess my question is really as follows:

What are ways that an Engineer gets the elevations of a land?

Aerial photos don't really tell you much unless you have those counters on the ground which give everything you need.

What are some other ways to get those elevations? I now know what to use to edit those lines or actually produce the site plan. All i need to know is how you would get htat information? Is there a databank that has elevations of land where you and I can download it and then put it in autocad and edit from there?


Thank you.

 

[MEM1]

vbp6us,

First, where are you located? You might check this site out.

http://terraserver-usa.com/

You can download aerialphotos and topographic maps from this site. It doesn't sound like you are looking for centimeter accuracy, so here is what I would do.

Hire a surveyor to do a topographic survey to produce contour lines, if you don't have the software to draw the contours, have the surveyor do it. He or she will have the software. Plane Jane autocad won't do the contours without some addin or a lot of lisp programming knowledge. Also have the surveyor mark any other features you want. Note, if you want the elevations of the land as shown on a topographic map, you will have to have the surveyor tie your survey into a bench mark with a known elevation, usually a section corner. Download the aerialphoto of the parcel of land you want from the site above. Import the aerial photo into autocad and scale appropriately. With a little moving and rotating, you can get the photo to match up with the drawing. It won't be exact, but will give you a decent representation of what is there. The best way to line the photo up with the survey is to have the surveyor mark the corners of a building or some other large object that is on the aerialphoto. When rotating and moving, move the photo, not the surveyors points. This way if you need additional shots, the surveyor can do the survey and dump it into the same autocad file so everything lines up as it should.

 

[vbp6us]

So engineers make site plans by hand? Manually? That is hard to believe.

I see what you mean about making one by tracing an aerial photo from Terraserver.

What about all these new GPS levels that give you readings which you can download onto a computer? How much do they cost?

I need something that gives me a fairly accurate survey of the land with all the elevations and trees if possible. Is there such a thing as this? What are these GPS levels now a days?

 

[TerryScan]

Ok, I work for a Civil Engineering firm. We acquire data for topographic information in the following ways:

1. We have survey crews. The use Survey instruments such as:
a. Total stations..ie electronic theodolites w/electronic distance meters and data collection. They acquire location and elevation at points to define topography and features. If you need to know more how this works...I would suggest elementry surveying books.

b. Survey grade GPS (Global Positioning Sattelite) equipment. I mention survey grade because it is far more accurate (and expensive) than hand held gps most people are familiar with. Again, location and elevation of features can be acquired with this equitpment.

2. Aerial Survey. This is not to be confused with simple aerial photos. To produce aerial survey, one must establish ground control (aerial targets) with conventional
equipment or GPS. A specially equiped aircraft takes aerial photographs in a special way (I am not well versed in the specifics, but one could research this). These photographs are post-processed in an office utilizing triangulation from the control points, overlapping photos, and perhaps data from the plane's position when taking the photos. Through this sophisticated "magic" what can be produced again is location and elevation of features.

These processes are a science. I don't think they can be sufficiently accomplished by one not versed in the principles required to produce the data.

Is this closer to answering your questions?

 

[vbp6us]

YES!

That's exactly what im looking for. Number one is what I need to do. I have an Optical level(auto level).

How much do these GPS Survey devices go for? >$500?

Thank you very much. Clearifies a lot!

 

[MEM1]

If you want a survey grade gps, be prepared to spend several thousand dollars. If you do decide this is the way to go, checkout Lieca or Trimble. Unless you are going to do a lot of these site plans, I would recommend hiring a surveyor. I do a lot of design work for feedyards in SW Kansas, over 100,000 thousand per year, but I still can't justify spending the money for a survey grade gps. If you have a buddy that will help you, you might see if you can find a total station, prism and prism rod. You might be able to find a good used one for 2 to 3 thousand. Checkout ebay, do a search for total station, you will come up with several hits.

 

[vbp6us]

I bought an optical level. Will that help? Whats the difference between that and a Total station?

 

[MEM1]

I'm not familiar with an optical level. Is this just a sight level? Do you have to have a level rod? If this is what I think it is, you can use it to get elevations, however, plotting points will be difficult unless you measure out a grid and take an elevation at each point where the grid lines cross. It can be done, but would take a while to do it. You could also run into problems if your parcel of land isn't square or rectangular. If you have the time to do this, start at the southwest corner of the property and call this point 100, 100. Measure 50 feet north this point will be 150, 100. Keep measuring 50 feet north until you get to the north end of the property. The last point at the north end of your property will most likely not be exactly 50 feet north of the previous point. This is okay, as long as you know how far the point is from the sw corner of the land, you can give it coordinates.

 

[MEM1]

Sorry didn't finish my last post. After you get the points flagged on the west property line, you need to measure 50 feet east of your first point. This point will be 100, 150. From this point go north 50 feet. This point will be 150, 150. Which means the point is 150 feet east and 150 feet north of the sw corner of the property. Your grid lines should be perpendicular to the property lines, or as close as possible. Your grid should look something like this.


x x x x x x x

x x x x x x x

x x x x x x x

x x x x x x x

x x x x x x x

x x x x x x x

Each "x" above would indicate a measured point. The bottom left x would be point 100, 100. The next x above the bottom left x would be 150, 100. The x to the right of the bottom left x would be 100, 150. I hope this is clear. I can't think of any other way of explaining it. What you would need to do after you have all the points flagged is set your level up in a place where you can see all of the points. Start at the bottom left point and shoot the elevation. This elevation is relative to a hypothetical elevation you would give to the point where you setup your optical level.

Example: Hypothetical elevation of point below optical level - 100 feet

You look through your level at the level rod and you see 5 feet.

The elevation of the point the level rod is sitting on is 100-5 = 95 feet.

Most level rods measure in meters or feet and 10ths of feet. So if you see two marks above 5 feet, this is actually 5.2 feet not 5 feet 2 inches.

This is actually a very simple and inexpensive way to get the elevations you are looking for. However, if your parcel of land has undulating terrain, this method will not give you a very precise topographic map. If your land has varying terrain, you will have to get an elevation at the top of all hills and the toe of each hill. This is possible with a sight level, however, getting the distance and direction of these points from your starting point will be difficult.

 

[vbp6us]

Hi,

Sorry I couldn't reply faster, I was out of town.

What is the difference between the following:

Automatic Levels
AL8-22 22X 200 feet Within 1/16" @ 100 feet

http://www.davidwhite.com/LOW-RES/8922.jpg

and

http://www.davidwhite.com/LOW-RES/47-4700.jpg

Thank you

 

[MEM1]

It appears the first link takes you to an sight level. This level requires you have a level rod and someone to lug the rod around so you can shoot elevations by look through the level, at the grid intervals as stated above.

The second link is a laser level. This can also be used for your purpose, but you only need one person (you). Set the level up make sure it is level, turn it on. It will rotate and shoot out a laser. This will require a sensor that you connect to the level rod. The sensor may beep differently depending on the position of the sensor. Whether it is above, below or level with the laser. Usually they will sound off a continuous annoying screech when the sensor is level with the laser. Set the laser up at the highest point on your property and call this elevation 500. Walk your predetermined grid. Check the difference in elevation at each grid intersection. Example:

Standing at the first intersection, you have to raise the rod 5 feet before you hear the annoying continuous screech. The elevation at this point will be your baseline elevation minus five. In this case 500 - 5 = 495.

Clear as mud isn't it.

 

[vbp6us]

Wow, Thanks a lot for the excellent information. I'll be back for more questions.

Do you have an AIM handle or Email? Thanks

 

[MEM1]

smurrison@cox.net

I will help in anyway possible.