mapping contours

I am not sure if this is in the right forum. Maybe there should be a mapping forum.

Anyway, I understand how to mark contours on the land using a bunyip or A-frame. However, how would one go about transferring these contours accurately to a base map? Triangulation works for almost everything else, but it would be very difficult for this.

Because of the scale and location of the project I am working on, I need to produce a very accurate, clear master plan map. And at this scale, and in a built up neighborhood like mine, obtainable contour maps mean very little.

I used this video, along with google earth and sketchup to create a 'fairly' accurate contour map of a parcel.

http://www.youtube.com/watch?v=y4J9sWEZR6E



Some things that threw me were making sure that things were square. Not sure how to describe it, and I'm not sure of your skill level with these software tools. I had to orient a straight line of the parcel with a straight line of the rectangle that you offset on contour. My parcel was at an angle to the origin, so I had to adjust things. Also, making sure to offset on an endpoint with the face of the rectangle. If that makes any sense, which it may not.

That video deserves an apple. I had no idea such a thing was so easily achievable. Thanks for sharing it Johnny

Landon Sunrich wrote:That video deserves an apple. I had no idea such a thing was so easily achievable. Thanks for sharing it Johnny

That video DOES deserve an apple. However, as to it being "easily achievable" - well, that's a whole other ball of wax. Perhaps if you are familiar with working with 3D modeling software it's easy. I really admire what's available in SketchUp - but it frustrates the heck out of me at the same time. And I fully admit that I may be a bit dim when it comes to getting the hang of 3D modeling software...

http://google-sketchup.en.softonic.com/

I'm going to give this free program 43mb a try to see if I can get anywhere close to what the geek in the video shows. But I don't need the contours so much as the free 3D design program might be fun.

Not sure if this will help the original poster of this thread, but if your in google earth program, and you simply want to know the elevation a an area, draw a line upon the area you want to see the elevation of with the 'ruler' tool, then find the name of the line over on the left viewing pane, Right click on the name of the line, and a menu will drop open, an click on: elevation profile ...a little window will automatically open that shows the elevations at various points of that line.

james beam

Landon Sunrich wrote:That video deserves an apple. I had no idea such a thing was so easily achievable. Thanks for sharing it Johnny

Thank you very much for the comment.

To be honest, I did come across it previously on this site. It helped me immensely when trying to do it for my piece of dirt, so I figured it would help others and save some people some searching time.

Hello Everyone,

Thanks for the advice. I was hopping some simple non-tecnological method was available, but maybe there isn't one.

I might try to use the Sketchup method.

http://store.usgs.gov/b2c_usgs/usgs/maplocator/%28xcm=r3standardpitrex_prd&layout=6_1_61_48&uiarea=2&ctype=areaDetails&carea=%24ROOT%29/.do

The USGS type contour map, is fairly accurate to establish elevation contours in relation to sea level, and if you don't like the internet version, I think you can order a paper contour map, I got mine a long time ago free at the local US forestry office. I'm not sure what your asking for... a less complicated method, other than maybe using a string & level, establish a specific location/elevation, and then measure various points from that established location. A surveyor's transit can be found at pawn shops, and can minimally establish level lines & distances in the field.

If I was trying to build a drainage ditch and I wanted to know what 'level' is at the highest elevation, and figure my drainage or drop of the ditch, tie a string & 'level line' onto a stake at the high end of the ditch, & tie the other end to a stake near the low end of the ditch, measure from the 'level line' to the deepest point of the ditch. If I didn't want the ditch to drain at all, I would tie the level line near the ditch upon wooden stakes, & grade the bottom of the ditch to be equal from the level line throughout the ditch. Hope that makes sense.

Oh I tried that sketch-up program yesterday...strangely wierd, wayyyyyyyyy beyond me! I can't even build a simple box with it, LOL, I'll keep playing with it, maybe I'll learn how to do something with it.

james beam

james beam wrote:Oh I tried that sketch-up program yesterday...strangely wierd, wayyyyyyyyy beyond me! I can't even build a simple box with it, LOL, I'll keep playing with it, maybe I'll learn how to do something with it.

You might want to check out this new (published on Jan 7, 2014) Sketchup tutorial series. He makes it easy to understand.

Sketchup Tiny House Design Lesson 1 by LaMar

Thanks Jim Porter for the link, I will check it out. I've read about 80 pages of the pdf. from sketchup (only 300 more pages to go...LOL) & watched a few related short videos, and I'm having fun learning the program, albeit I have a long, long way to go to model anything really complicated.

I'm not confident enough yet to even attempt the contour/elevation trick 'The Geek' instructs in the earlier posted video~~~but I'm working toward it!

james beam

Hey Gilbert - I can't tell from your OP what the size of the site actually is! it sounds like less than an acre? Using building baselines is one option (if you have a square building to build a map off of). Another is a "map table" where you are recreating the visible world around you by taking bearing and distance measures with a sighting instrument attached to a scale (home-made) and a tape measure (100'). If I guessed site size right, I might try to explain more.

Hello Paul,

Yes, the site is only a quarter acre. And there are some buildings on it.

I would be interested in hearing more.

Here's a nice video about using a plane table with a lovely highland lilt. I have made an aladade using a piece of tape attached to a scale drafting ruler with a tack, and a card table. The alternative would be to use your rectalinear building, rather than a survey station, as your starting point. From a square, you can run eight lines, two from each corner, using the edge of the building to keep you line straight with the edge of the building. You can then use a tape and offset approach o identify points. Either way, surveying is just a process of locating points.

http://www.youtube.com/watch?v=Eyw3dsvOYjA

Here's another video on tape and offset.

Jennifer Wadsworth wrote:

Landon Sunrich wrote:That video deserves an apple. I had no idea such a thing was so easily achievable. Thanks for sharing it Johnny

That video DOES deserve an apple. However, as to it being "easily achievable" - well, that's a whole other ball of wax. Perhaps if you are familiar with working with 3D modeling software it's easy. I really admire what's available in SketchUp - but it frustrates the heck out of me at the same time. And I fully admit that I may be a bit dim when it comes to getting the hang of 3D modeling software...

I'm familiar with graphics programs. I plan to make a model of my new farm. Once I get the hang of it...gimme a week or two. I will do one for you if you wish. I don't know what you would use the output for but I just thought I'd offer. It helps me to do a task if I give it a deadline. btw it is no charge thing. I would nice to give back something to these forums that's helped me so much.

The first time I used that video (the one I re-posted) as a guide, it took me an hour+ to make something coherent. I did it at a computer other than mine, which was a Mac. The Mac skeptchup model wouldn't open on my home computer, so I had to re-do it. The second time only took me about 10 minutes to get the same thing.

I still think the sketch up way is for a very general understanding of land-lay. Probably more useful for radical changes in elevation, rather than gradual. My site is approx 3% grade and I feel fairly confident I could get much more accurate with a sight level and a friend. I can see inadequacies that just aren't represented with the google earth resolution. Maybe accessing GIS data from nasa survey's, but that's waaaaay more technical.