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Topographic map for housebuilding plans


Ferronovum

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I tried to preview a new thread but i had some links in it so everything dissapered

 

So just shortly this is what I'm looking for:

 

Topographic map i.e. Situation plan with roads, walls, rock, grass, parking place and so on...

 

I have:

AutoCAD 2009

6 poles marking the border in reality

xy coordinates in a local grid for the poles

Maybe locate the ref. pole(x=100,y=100) when I start triangulate tomorrow(using large nails, meassuretape, a waterlevel with laser on a tripod and of course a pen and paper:P )

 

 

I wonder:

Best method to create the plan (3dmesh, triangulate....) and how to do it

Best way to store the data from my meassure (LandXML, xml, excel, asciifile with xyz......) and how to import it to autocad

How do I best mark what's road, grass, buildings, cabels in ground and so on?

How do I change the elevation or make a hole for placing a house with foundations and draining

 

I have searched the forum but only found small pieces and no complete view of the matter.

The pdf is an example of what I plan to do.

I have a deadline when I need to be done to apply for permission to build.

Byggnadsexempel_sit_plan_sektion.pdf

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I am thinking the easiest way (if you are using regular AutoCAD) to import the ascii file is to open it with SiteTopo. This will automatically triangulate and create the surface. Then you will need to add any necessary breaklines (edge of pavement, top of banks, toe of slopes, etc.) to keep it from triangulating across features such as roads and ditches.

 

Then you can go to file > saveas > and save the 3d faces (and contours and points if you want them) to .dxf and open in AutoCAD. Then you can apply materials as desired.

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If you had survCAD you could actually store all the data as points, and all the information you described would be assigned to the individual points. Also, it would contour & triangulate for you by use of the points.

 

You could actually triangulate every object from 2 of the known x,y post coordinates & get remarkably accurate location if you have a water level & could get access to a theodolite. SurvCAD allows you to draw using survey notes. If you had the time & survCAD, you could actually triangulate the roads & ditches by recording topo ground shots in your survey. This would require a theodolite though, and I'm assuming you are going to use a grid or something.

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If you had survCAD you could actually store all the data as points, and all the information you described would be assigned to the individual points. Also, it would contour & triangulate for you by use of the points.

 

You could actually triangulate every object from 2 of the known x,y post coordinates & get remarkably accurate location if you have a water level & could get access to a theodolite. SurvCAD allows you to draw using survey notes. If you had the time & survCAD, you could actually triangulate the roads & ditches by recording topo ground shots in your survey. This would require a theodolite though, and I'm assuming you are going to use a grid or something.

 

Hi, sadly I don't have access to a theodolite. I just have that water-level with laser on a tripod(not selflevelation) a 20meter measuretape and two regular 2 meters measuresticks, a hammer and large nails, pen and paper.

Am think of getting a selflevelation laser-level and measureinstrument with laser but that's up to my dad who "pays the bill".

 

The evelationlines is 1 meter and I guess I can get a tollerance within z=+-5 cm and xy=+-3 cm if I compensate for z when I measure.

 

Todays To Do list:

Breakfast first.

Print sheets in excel so I have something to write the data on (point name, ref1, distance, comp z, ref2, distance, comp z)

(I know, this will give me two points but I mark the points aprox. on a handdrawn map)8)

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I am thinking the easiest way (if you are using regular AutoCAD) to import the ascii file is to open it with ****** This will automatically triangulate and create the surface. Then you will need to add any necessary breaklines (edge of pavement, top of banks, toe of slopes, etc.) to keep it from triangulating across features such as roads and ditches.

 

Then you can go to file > saveas > and save the 3d faces (and contours and points if you want them) to .dxf and open in AutoCAD. Then you can apply materials as desired.

 

Your reply gives me two questions:

1. Structure of the ascii file (I use Notepad and notepad++ for ascii)?

Does it look like LandXML:

[b][font=Courier New][color=#ff0000]Here goes an example of LandXML code but an annoying spamrule make me unable to post it, same rule that made my first post disapere[/color][/font][/b]


 

2. Where and how do I add the breaklines?

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I wonder:

Best method to create the plan

 

Some people spend three years at college trying to learn this :shock:

 

I hope you are a fast learner!

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Some people spend three years at college trying to learn this :shock:

 

I hope you are a fast learner!

Well I got until the middle of March.:? At the moment am I trying to make a formula in excel using some kind of trilateration(or bilateration in my case, only have two fixed points that are close enough)

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However you do the calculations, the accuracy comes from horizontal (plan) distances. Usually with tape measuring, you do not realise how out of flatness is the tape, and you will end up measuring hypotenuse distances rather than flat distances. And watch out for sagging tapes!

TapedDist.jpg

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This is a correction to my previous picture, with a more likely scenario with a taped dimension. Just so long as you know what can happen, you can make allowances to minimise any errors. :(

ActualTape.jpg

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This is a correction to my previous picture, with a more likely scenario with a taped dimension. Just so long as you know what can happen, you can make allowances to minimise any errors. :(

Well, i am aware of the compensation I need to make with pythagoras theorem. But the curvation due to the weight of the measuretape that will I ignore cuz the tolerance is not that high. If I wanted higher accurancy I would have contracted a geo-firm with real gps and laser instruments. But that would cost my around 1-2 000 $ and I rather spend some time outdoor.

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In that case, I would suggest that you collect your information as sketches with dimensions on paper, then draw directly into AutoCAD. Use AutoCAD to do your calculations, you will find that far quicker and easier :D

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In that case, I would suggest that you collect your information as sketches with dimensions on paper, then draw directly into AutoCAD. Use AutoCAD to do your calculations, you will find that far quicker and easier :D

Well thats probely trued but I want to process the data as far as I can before puting it into AutoCAD. Working on a sheet in excel that will take any two ref.points in xy and return two points depending on distances. One of the points will be rejected by user.

The math I use is a halfway trilateration. will post the excel file when I'm done with it. The functions are swedish so to use them you will probely have to change them.

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This is how the excel-file looks like now, somewhere I messed something up cuz the return values doesn't add up.

I used formulas from Univ of Georgia in a document called From Barns to Satellits... (GPS trilateration). In fig 3 (second of the circles) views what I'm looking for, I want to calc B and B1. If I go all the way as in fig 5 due to measuretolerance I won't get a uniqe point.

 

Calculation are in sheet2 (Blad2)

 

Anyone know where it went wrong?

 

:P Correction: Found the error. Was displaying degrees instead of radians and forgotten to transform back to radins before next calculation:shock:

Trilateration.zip

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Well thats probely trued but I want to process the data as far as I can before puting it into AutoCAD. Working on a sheet in excel that will take any two ref.points in xy and return two points depending on distances. One of the points will be rejected by user.

The math I use is a halfway trilateration. will post the excel file when I'm done with it. The functions are swedish so to use them you will probely have to change them.

 

It sounds a good college project. Unfortunately, as no surveyor (that I know) who is trying to make a living would do it your way, you will have to re-invent the wheel. I can only wish you every success and I can't give you any assistance in your chosen method of working. :(

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It sounds a good college project. Unfortunately, as no surveyor (that I know) who is trying to make a living would do it your way, you will have to re-invent the wheel. I can only wish you every success and I can't give you any assistance in your chosen method of working. :(

Not re-invent the wheel but find it :geek:

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Your reply gives me two questions:

1. Structure of the ascii file (I use Notepad and notepad++ for ascii)?

Does it look like LandXML:

[b][font=Courier New][color=#ff0000]Here goes an example of LandXML code but an annoying spamrule make me unable to post it, same rule that made my first post disapere[/color][/font][/b]


2. Where and how do I add the breaklines?

 

1. I believe it can simply be an ascii file with a format of X,Y,Z. There are several formats that SiteTopo can decipher. You would have to look at the site and/or download it and go to File > Open > and you'll see the different formats. You might have to select Point File to see the point file formats.

 

2. For breaklines you just double click a point, then double click the next point to connect it to (This is in SiteTopo). It draws a line, a.k.a. "breakline" or "feature line", between the points. This stops triangulation across feature defining lines. For example, you don't want your surface to triangulate across the centerline of your road where there is a crown or valley. You don't want it to triangulate across your edge of pavement line or top of bank line, etc. A breakline connects points such as the edge of pavement points, top of bank points, centerline of road points, flowline of ditch points, etc. disallowing triangulation across (ie - a toe of slope point won't be connected to a centerline of road point, etc.). You follow?

 

If this is for a school project and not site specific you could just download free topo data and use that if just for presentation. That would save you gobs of time. (I haven't thoroughly read the entire thread so not sure what the purpose is.)

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Another way to get the points into AutoCAD would be to use the importxyz lisp on Jeffrey P. Sanders' site, but I don't know about doing the TIN or MESH from them that way except for manually adding 3d faces and well, that could take a while. Then you would still need to add breaklines somehow.

 

So much easier with a civil cad product. Civil 3d, survcad, microsurvey, carlson, eagle point, so on and so on.

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Another way to get the points into AutoCAD would be to use the importxyz lisp on Jeffrey P. Sanders' site, but I don't know about doing the TIN or MESH from them that way except for manually adding 3d faces and well, that could take a while. Then you would still need to add breaklines somehow.

 

So much easier with a civil cad product. Civil 3d, survcad, microsurvey, carlson, eagle point, so on and so on.

Well I'm aware of that but everything costs and I already had AutoCAD 2009.

 

I have SiteTopo now(freeware) and looked into the LandXML sample file and liked the structure so I probely hardcode a LandXML-file with my collected data after I have ran it through my Excel sheet. Working on a ture/false routine to check A and B in those case I have a third referens point. I'm pretty used to hardcode large amounts of data. Started when I wrote my first homepage in notepad on a 386computer many years ago. Many highlevel programs just add too much spam to the code.

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1. I believe it can simply be an ascii file with a format of X,Y,Z. There are several formats that SiteTopo can decipher. You would have to look at the site and/or download it and go to File > Open > and you'll see the different formats. You might have to select Point File to see the point file formats.

 

2. For breaklines you just double click a point, then double click the next point to connect it to (This is in SiteTopo). It draws a line, a.k.a. "breakline" or "feature line", between the points. This stops triangulation across feature defining lines. For example, you don't want your surface to triangulate across the centerline of your road where there is a crown or valley. You don't want it to triangulate across your edge of pavement line or top of bank line, etc. A breakline connects points such as the edge of pavement points, top of bank points, centerline of road points, flowline of ditch points, etc. disallowing triangulation across (ie - a toe of slope point won't be connected to a centerline of road point, etc.). You follow?

 

If this is for a school project and not site specific you could just download free topo data and use that if just for presentation. That would save you gobs of time. (I haven't thoroughly read the entire thread so not sure what the purpose is.)

 

Yeah I follow. Still like the LandXML structure. Maybe make the points in xml, load it in SiteTopo and add the breaklines etc, save it in LandXML and see what I get. Would be nice to not have to hardcode every triangle.

 

No, this is absolutly not a school project. Its a real site, its my grandparents summerhouse. Take a look in google Earth at my location. I have the spare time to do it this way and hopefully will I learn some new stuff down the road.

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