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Survey points and COGO points - AutoCAD Civil 3D Tutorial

From the course: Cert Prep Autodesk Certified Professional: Civil 3D for Infrastructure Design

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Survey points and COGO points

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- [Instructor] To begin our chapter on points. Let's first look at the difference between survey and Cogo points. And by the way, Cogo stands for coordinate geometry C O G O. Now the best way to show the difference, is to see how they're brought in to civil 3D. And we'll start with Cogo points because it's a simpler process. Going to open a drawing called import points. And then to start the process, I'll go to the insert tab of civil 3D and click points from file. I'll click the green plus sign to select my point file. And for this example, I'll choose the point data dot TXT file. The format for this is P N E Z D comma delimited. You want to pick that carefully or your points may end up in the wrong place or your Northings and Eastings could be reversed. I'll go ahead and click okay. And you can see the points have been inserted into the drawing. Now I'll point out a few things that may seem strange but they'll become important when we compare these to survey points. If I go to prospector, you'll notice if I click on points the points are listed and I want you to pay attention to this icon and its appearance. Try to store that in your memory. Also notice that if I click on a point, I can click and drag it and move it into a different location. Very easily no problem. And another thing I'll point out, that's not as obvious is that these points actually live in this drawing file. And again, that may seem like a strange thing to point out but you'll see that when we do survey points it's a bit different. So let's do that now, let's import these same points into a different drawing but this time we'll do it as survey points. I'm going to go out and open the drawing called survey data. And this time I'll go to the home tab of civil 3D and under create ground data I'll click import survey data. So it's a completely different command. The first thing we'll need to do is either create a new survey database or pick one that's already been created. I'll create a new one and I'll call it survey two. Next I'll edit the survey database settings. And I want to make sure in this case for this example, that my points are set to US foot. Basically, anytime you're working with survey data in the United States you're going to want to use this US foot or possibly metric option. You wouldn't want to use the international foot option in the U S that's going to cause you problems. You can see there are lots of other settings here but for now that's all we're going to worry about. I'll go ahead and click next. Then I'll choose my point file. And we are going to choose a different data file that's formatted a bit differently and we'll cover that in a later video. For now, just know that the data is similar. It's going to use the same P N E Z D common delimited format as the first example. I'll click next one of the differences with survey point data is that it can become part of a network, perhaps a travers that can be balanced. In this case, we don't have any traverses in our data but it's important to point out that this is a capability of the survey functionality in civil 3D. So here we have some more survey database settings that have to do with the data that's coming in. And let's talk about a few of these. The first thing we'll notice is that we can process linework during import, if this isn't turned on and if you're following along with me, go ahead and turn that on. Also we can insert figure objects and also we can insert survey points. Now, I pointed out in the previous example, that the points that I brought in actually lived in the civil 3D drawing. When you're dealing with survey points, the points live in the survey database that survey two database that we created a few seconds ago. That's where the actual data lives. And based on how your office is set up, you may have it, so that only surveyors are able to access that survey database. So if you're an engineer you can open a drawing with those survey points visible in it, but you can't make any changes to those survey points because those changes have to be done by somebody who has access to the database, that's behind them. We'll be able to demonstrate that a bit later . Processing line work means that we can have line work codes built into the data that basically tells civil 3D how to connect the dots when the data's coming in. Again, something else unique to survey data and those are the figure objects here. So this kind of goes hand in hand we process the line work during import which is kind of like playing connect the dots and those lines become figure objects which we can then import into the drawing. Again, they are stored in the survey database along with the points and we get to choose whether they're displayed or not in the civil 3D drawing. Okay, I'll go ahead and click finish and we'll see that data come into the drawing. So you can see obviously there's a difference here. In the previous example, and if I flip over to that drawing, you'll see that we just got points. There's no line work included. Whereas in this example, we got the line work in white some buildings and some roads. We did also get the points and we got some tree symbols as well, that's all part of the automated line work and symbol creation. Now the symbol creation is a different functionality called description keys but the line work you see here is made possible through the survey functionality. So that's one of the differences with survey points is that as we bring them in, we can draw these figures automatically through them. If I go to prospector and click on points, you'll see that there are points listed here but notice the icon it's different than the icon we saw in this drawing. Let's compare And that's a visual indicator that these are Cogo points and these are survey points. They've got a survey target icon next to them. And if you remember in the import points drawing I was able to just grab a point and move it. In this drawing, I'm unable to do that. Notice as I click and drag, the point does not move. It stays put. In order for me to edit that point, I would need to go into the survey tools to make that change. And you can see some of those commands up here on the contextual ribbon tab that has popped up like edit list points, point group properties and so on. These are the tools I would have to use to edit this point. And again, if I weren't a surveyor in my company, I probably wouldn't have access to the survey database in order to make those changes. So it's an extra measure of protection so that surveyors can be sure that their point data and the other data that they create is safe from other people in the office, inadvertently making changes or changing the integrity of the data. So there you see the difference between survey points and Cogo points.

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