Discover the differences and uses of survey points and COGO points within Civil 3D. This article will guide you through how these points are displayed, their respective icons, and how they can be edited.
Key Insights
- Survey points and COGO points are the two types of points you'll encounter in Civil 3D. Survey points are displayed on both the Prospector and the Survey tabs, while COGO points are only displayed on the Prospector tab.
- Each type of point is represented by a distinct icon: a survey target for the survey points, and a circle overlaid on crosshairs for the COGO points. These symbols can be viewed in the Prospector tab under "Edit Points".
- The editing capabilities differ between survey points and COGO points. Survey points cannot be moved or edited without accessing the Survey Database and using specialized commands. Conversely, COGO points can be moved using basic non-Civil 3D drafting commands, and can be edited in the properties window.
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So before we get to creating points inside of Civil 3D, we're going to have to understand the difference between two types of points that you're going to encounter inside of Civil 3D. These points in Civil 3D are either survey points or coordinate geometry points, often referred to as COGO points. In this video, I'm going to go over the differences between these points, but we are not going to be doing any drawing, so please just follow along and take notes, but do not try and do anything in the drawing.
So on the left-hand side, 0.578 is a survey point, and on the right-hand side, 0.579 is a COGO point. The difference between a survey point and a COGO point is that survey points are displayed on both the Prospector and the Survey tabs, while COGO points are only displayed on the Prospector tab. So as we discussed in the previous video, the Prospector tab is located on the left-hand side of the screen in the Tool Space window.
So inside of the Prospector tab, if we go to Points, and we right-click and select Edit Points, the panorama window will come up, and inside of the panorama window, you will notice that we have 0.578 and 0.579. That's because this is the points located inside of the Prospector tab, which shows both Survey and COGO points. If I select the checkmark to close this window and move down into the Survey tab and select the Survey tab, I'm going to go ahead and open my Survey Import for Editing, and I'm going to go ahead and look at my Survey Points. I'm going to right-click, and I'm going to go to Points and Edit Points.
Inside of this panorama window, you'll notice that I only have 0.578, and that's because we are in the Survey tab of the Tool Space window, and as we've stated before, Survey Points are displayed in both the Prospector and Survey tabs, whereas COGO points are only displayed in the Prospector tab. So 0.579 does not show up inside of this panorama window because it is not a Survey Point. I'm going to go ahead and check the box to close the window, and we'll move on to the next difference.
Survey Points have an icon next to them that looks like a Survey Target, while COGO points have an icon next to them that looks like a Circle Overlaid on Crosshairs. We can see these differences if we go to the Prospector tab, we go to Points, we right-click, and we select Edit Points. Inside of the panorama window, you'll notice that 0.578 has a different icon than 0.579, and the difference is that one is a Survey Point with the Survey Marker symbol, and one is a COGO Point with the Circle Overlaid on top of a Crosshair.
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Moving on, I'm going to select the check mark to close the window, and you'll see Survey Points can't be moved or edited without accessing the Survey Database and using specialized commands for editing Survey Points, while COGO Points can be moved even using basic non-Civil 3D drafting commands. So, for example, if I select 0.578, our Survey Point, and I select the Grip Edit, and I try to move that point, you'll notice that Civil 3D is not allowing me to move this point, and if I select anywhere on the screen, the point does not move. If I initiate a Move command by typing M and hitting Enter, and selecting a point anywhere on the screen, and moving that point, you will notice that the point appears to move, but as soon as I select my second point as my displacement point, that point will bounce back to its original location because it is a locked Survey Point, and it cannot be moved by using generic AutoCAD commands, whereas if I select the COGO Point, I can Grip Edit by selecting the Grip Edit and clicking a location for it, or by initiating a Move command
by hitting M, Enter, selecting anywhere on the screen, and moving the point to a new displacement location.
The additional way that you can go about changing these points is by going and right-clicking in the Tool Space button over Points and selecting Edit Points. You'll notice that in the Panorama window that my Survey Point is grayed out for Easting, Northing, Point Elevation, and Raw Description, whereas my COGO Point can be edited by changing this table for a Point Number, Easting, Northing, Point Elevation, and Raw Description. Now if you want to change the location or the elevation of your Survey Point, you would have to go to the Survey tab of the Tool Space, you would have to go to your Survey Points inside of an Import Event, and you would right-click on Survey Points, select Points, and click Edit Points.
Inside of this Panorama window, you'll notice that we have only our Survey Point 578. However, the Easting, Northing, Elevation, and Description are now able to be edited, and that is because they are inside of our Survey Database and can be changed. Now if you would like to change your points using regular AutoCAD commands, you can unlock your points and allow them to be edited using standard AutoCAD commands.
In order to do this, you have to go to your Survey Points, right-click, and select Unlock in Drawing. If you unlock points from a Survey Database in your drawing, they can be edited by anybody who opens the drawing, whereas if they remain inside of the Survey Database, only users who have access to that Survey Database can make modifications to those points. Lastly, Survey Points cannot be edited in a Properties window, and COGO points can be edited in a Properties window.
As we saw previously in the Prospector tab, under Points, Edit Points, and in the Panorama window, we had the Survey Point being grayed out in this upper line and the COGO Point being editable in all of these entities inside of Easting, Northing, Point Elevation, and Raw Description. Similarly, if I was to select a point, right-click, and choose Properties. My Properties window, if I scroll to the bottom, will have my geometry for my point, and you'll notice that Easting, Northing, and Point Elevation are grayed out and not editable.
However, if I unselect my Survey Point, select my COGO Point, and scroll to the bottom of the Properties window, you'll notice that my Easting, Northing, and Point Elevation is editable for a COGO Point.
