I've only been using SurvCE for about a month, so I'm still pretty "green" when it comes to terms etc. I keep seeing this term pop up when I'm searching their forum or here. I've never used one before, and don't really understand the concept behind using a control file. What is it and exactly how does it work? I typically do worksheets based on what subdivision I'm in, or section I'm in etc. so our coordinate files do get quite large at times. Is this a manner of reducing the size of the file the draftsman has to handle when a job is completed? Like I said, I'm not sure exactly what a control file is, or how it works, it's not really explained all that well in the manuals I have.
Any crd file can be used as a control file. Very handy when you want to use a few points from a previous job without having to clutter up your existing file with a thousand topo shots that are also in the previous file.
Say you have a control network that encompasses a whole subdivision and now you're going to start laying out individual houses. You can load the file for the network as the control file and then use a separate file for each individual lot. The points in the control file are available to use for resections, occupations, backsights, calculations, etc but they don't clutter up the file for the lot and you can re-use the control file each time you need to work on a lot in that subdivision.
Stephen Ward, post: 359449, member: 1206 wrote: Any crd file can be used as a control file. Very handy when you want to use a few points from a previous job without having to clutter up your existing file with a thousand topo shots that are also in the previous file.
Say you have a control network that encompasses a whole subdivision and now you're going to start laying out individual houses. You can load the file for the network as the control file and then use a separate file for each individual lot. The points in the control file are available to use for resections, occupations, backsights, calculations, etc but they don't clutter up the file for the lot and you can re-use the control file each time you need to work on a lot in that subdivision.
You also want to be sure you understand how SurvCE handles duplicate point numbers when you use a control file. I can't remember if it gives priority to the control file or the job file when a point number exists in both. I avoid the situation by picking a beginning point number for the job that will be different than anything in the control file.
I was just fixing to ask this. Seems like it could get confusing. What if you set new control in your job file? Is that reflected in the control file? Seems like an extra step where potential new control could get overwritten or excluded. I get the idea now though, and it makes sense as I have some coordinate files with 15 to 20 thousand points in them. I would be willing to bet only 10 or 15 percent of those points are control points, the rest are topo/location points.
When I first started with SurvCE I somehow had USE CONTROL FILE checked. I was using it without knowing it. Got me really screwed up. So I have never used it. With thousands of points in a file I'm sure it's very useful when used correctly.
So "control point" might mean pre-calc'd staking points, search coordinates, etc, AND points that are survey control.
It is useful to have these in a separate file, so that your new job is all new information. This is helpful when importing into CAD files and such.
The control file is selected under the Job Settings button, and in the same area there is a tab for staking settings. There you can choose to give the control file priority for staking out, if you have the same point number in both files.
There is some caution, if a point has the same number in both files and you use it as survey control (occupy or bs point), it prioritizes the current job, not the control file.
-David
hlbennettpls, post: 359464, member: 10049 wrote: I was just fixing to ask this. Seems like it could get confusing. What if you set new control in your job file? Is that reflected in the control file? Seems like an extra step where potential new control could get overwritten or excluded. I get the idea now though, and it makes sense as I have some coordinate files with 15 to 20 thousand points in them. I would be willing to bet only 10 or 15 percent of those points are control points, the rest are topo/location points.
As others have pointed out, the control file is just another CRD, which can be created with your desktop software, or imported into the DC from an ASCII or TXT file easily. It doesn't get overwritten by any new observations taken. It's "static". It only gets overwritten if you over write it, and even if you do that by mistake, you can put the file that was there originally (put there by you), again.
I use it for control points that I've established, or points from previously done surveys. You can then use them for exactly what they are...control points; resect from them, cross ties, etc.
I do remember (not so long ago), being confused on how to create them, and activate their use. But once you have that down, it's pretty simple.
