Accurate Location of Model

Good Evening

I’m hoping someone can help me with accurately locating a model with geolocation.

The situation is this;

  1. A client has used the Trimble Surveying device to undertake a survey of a site and it has worked really well. It created really accurate point information.

  2. I imported the DXF that the Trimble device generated into AutoCAD. I had to scale it up by 1000 but other than that, it was perfect. Saved as a DWG.

  3. I imported the DWG into Sketchup and using TopoShaper, generated the terrain in no time. All good so far.

So, what I’m wondering is if there is a way to accurately locate this model so that the Points generated by the Trimble survey device are in the correct place. I can’t seem to think how to do it. I can geolocate the model by searching for the location but don’t seem to have a way of geolocating an exact point.

Essentially, what I want to do is to ensure that the Model is in exactly the right place so that the design I am producing can then be plotted on site using the same Trimble device.

Can this be done is Sketchup, or do I need an external service to plot the points on a Map which I can then import as an image?

Hope that all makes sense.

Mike

When you Add Location you could type in a zip code or street address, and zoom in on the bit you’re interested in, or you can enter the latitude and longitude. If the Trimble equipment gave that, then just type in the numbers.

If not, you could use Google Maps, and right-click on a point of interest, and select What’s Here? That then shows the latitude and longitude in a box at the bottom of the window, and you can copy those numbers and paste them into the Add Location dialog in SketchUp.

My desk is here: 40.018284, -105.242323

Hi Colin

I’m very curious in the correct workflow for this and it seems like you may be able to help.

My understanding/experience is that survey captures/scans and engineering data are all coordinated to a basepoint.

  • For construction projects that ‘basepoint’ tends to be a known (physical) mark on the site (a stake on the corner of the site boundary)…this context is Michael’s issue above and your solution seems to be a good one, although we also need the Z value, don’t we??)

  • For larger projects or projects where construction isn’t fully underway yet, the local trig station is used as the basepoint for all work prepared by surveyors, the various engineers and other consultants. But this point is often several miles away (sketchup doenst like that).
    SketchUp files, and anything imported into SketchUp, however, need to be manually located. This causing extra work (creating basepoints to snap to) and adds a high degree of risk if we manually locate it in the wrong place or if it has the wrong rotation due to a slightly different geodetic system.

Most software seems to have no trouble with far-away basepoints and reading the coordinate systems. I assume this is partly because, in addition to a modelling origin (basepoint) it also has a “world origin”) to which all imported/exported data can be associated. The world origin can be 3 miles way or 3000 miles and it would not matter to the modelling engine.
SketchUp’s world origin and coordinate system of WGS2000 seems to be incompatible with the files created by surveyors in my part of the world. Can Sketchup have such a function in a way that relates to other software and coordinate systems, not just WGS or Latt/long?

Much appreciated
Sam

I’m sure lots of people here know more than I do about this stuff, and I would expect a definitive answer to appear in a short while!

I don’t know about basepoints, and can see that SketchUp’s limit of grabbing terrain that is only 9000 feet diagonal would be a problem if the stake in the ground was say 10,000 feet away from where the house needs to be. You can add more imagery though, not sure what the upper limit is, but I put four areas together, which got me to be over 36,000 feet away from where the basepoint might be. Is that typically less than the distance in a real world case?

There are extensions that can import SHP files, would something like that help?

As you can see, I don’t know much about this topic, but is there something wrong with my solution of using latitude and longitude as a way to grab the right bit of land?

Correct me if I’m wrong: the longitude and latitude entered, when geolocating, refers to the position the UCS origin is when long/lat was entered. Since the x/y/z point in space only refers to a singular point, be sure to set North correctly as well.

We really do require the Z-value as well if we’re going to the extents of geolocating.

@MichaelSiggers

Question about what you are hoping to achieve. Is the end goal to see the design and the terrain model positioned on a map that extends outside the project site OR to just make sure the design is positioned correctly on the site terrain you created?

If the later, are any of your initial survey points discoverable on the real-world project site?
If you have 2 points, they could be used to designate the origin (0,0,0) and the direction of the X-axis from which the design would be positioned.

Once you have this set in the model, you can accurately position the design based on the X,Y,Z coordinates relative to the designated project origin

CD

@ChrisDizon

If you’re working as part of a team, especially when there is some kind of BIM workflow / expectancy (probably deliverables dependent), then it needs to be accurate X / Y / Z.

Hello Julian

I updated my comment to reflect this

Thank you for all the replies @ChrisDizon @Julian_Smith @colin @AK_SAM Really appreciated.

I did some more digging today and spoke with a representative of a company here in the UK called Sitech, who are an authorised dealer for Trimble equipment.

He informed me that the only way of accurately locating the survey data points is to use Trimble Business. This software is linked, I think, to the equipment, and can import the points and overlay them on the map.

I do have the information from the survey, and in one of the Text files it does give Longitude and Latitude but I can’t seem to see which point it relates to. It seems to give these values for Station points (?) and not for the individual points created by the Survey. These ‘Station’ points are not shown in the DXF file. When I use the values for Latitude and Longitude, it does show the right area surveyed, using Geolocation in Sketchup. I just don’t know where these points are.

If I new, I guess I could move the model so that point is at 0,0,0 and then geolocate by specifying a Longitude and Latitude, assuming Sketchup places the origin at that point.

The area surveyed contains approximately 30 points, which were imported and then terrain created using TopoShaper. In the Solid I have generated, the points are still there as a separate group, on their own layer.

Thinking ahead, and the fact that Trimble manufacture the surveying equipment as well as develop Sketchup, it would be nice if the equipment and Sketchup could talk to each other, so that survey data could be used to accurately place the model.

Mike

Trimble’s Realworks software exports point data (or user-generate data using a point-cloud) directly into SketchUp but you have to select (manually) a project basepoint. I’m still learning it. I don’t think its as easy as the process we are asking for.

Also, a Realworks license costs $9,000 (and ties to a Trimble scanning total station worth about $20,000)

Yes, I’m pretty sure the Client I’m working for has the Trimble Total Station, (May have the devise incorrect there), as that what he used to provide me with the Survey data which I used to create the terrain.

Is there then some way I can provide him the finished model to put back into the Station, to use for setting out in site?

Have a look at Trimble FieldPoints or PointGadget2 extensions for SketchUp

These will allow you to bring in points from a total station, shoot additional design points while in SketchUp and then export the points back out to be used in a total station.

CD

Ah, I’ll have a look at them.

Do they not have to rely on the Model being accurately located though?

@MichaelSiggers

If you are shooting design points marking elements of the model, they will be accurate. The points shot in SU will be relative to the SU project origin, just like the field points. If you are able to get a CSV of the points that were shot out in the field or if you can upload the DXF you used, I can try to work something up to help explain.

CD

Thank you @ChrisDizon. I’ll sort out the information to send across, along with the terrain model I created from the survey points.

I had a look at the Point Gadget 2 videos and it looks really good.

Mike

Fully agree - currently in the same boat, learning/practicing with Trimble TX8/Realworks and SketchUp. (and thinking more and more about Undet, with only one thing stopping at the moment - it don’t support TZF’s directly and will require extra export. From what I understand.)

Really seems that Trimble is missing by not getting a better integration between SketchUp and their scanners/total stations.

SHP files help because (if they have been generated from any sort of GIS software) have been assigned an origin point that relates to the local co-ordinate system. This is similar to anything you receive from a survey or civil engineer.

The problem is that Sketchup imports the geometry either

  • at 0,0,0, which means the location is not accurate.
  • imported “with location” which usually results in model geometry which is 100s of miles away from the 0,0,0 origin and makes Sketchup impossible to use.

SU needs a way for the model’s 0,0,0 point to be located where the geometry is, but also have a “model origin” which could be 1000s of miles away. This model origin would only need to be used for import/export (in the same way that the Latt/Long coordinates work now). I can confirm Trimble Business Centre doesnt make this process any easier…its the same as “import with location”.

@MichaelSiggers You likely need to get your data into a format that uses the project’s co-ordinate system. I’m not sure if the Trimble device can read a SKP file …- depends on the model and I suspect it will need to go through Trimble Business Center or some other app to convert it (to DXF/DWG etc). Essentially it needs a base point that the survey instrument can read.

You’ll need a go-between file; something sent to you buy a surveyor with a known point in it.

The easiest way is to get the surveyor to create a boundary for you with a Mark on the corner (a basepoint) and then snap your model to this. When you send it back to him/her, include that Mark within your model so he/she can snap it into the right location. It does require communication and coordination, and is not without risk (watch out especially for slight rotations in the model. A Mark with a Cross shape or north arrow is best to overcome this).

The other methods are more complicated but better if you are repeating the exercise numerous times.
There is a trick that works thus:
Import some Survey information “with location” which will be 100s of miles from 0,0,0. Instead of trying to model there, just create that geometry as acompponent and save it out to a new SKP file. Then, work on that SKP file. Once finished, go back to the original SKP file which is 1000s of miles wide, and “update” (replace) the component to the one yu have worked on. It will appear at its original coordiate. However this process falls over with very complex files, and you don’t have the ability to check your final file for accuracy.

Using Latt/Long coordinates is a method similar to the Basepoint/Mark method, which still requires a basepoint Mark to be identified by the project team and coordinated. I find that Latt Long coordinates on their own are more error prone becuase it’s very difficult to spot if things are sitting right - with a piece of geometry (Mark or cross) set at zero elevation, you will know if your imported/exported data matches up and is rotated correctly.

I was hoping there would be an extension/app to handle this but I haven’t managed to find anything so far.
Trimble Connect might have some tools that are worth looking into - anyone looked at that??