Geographic Location GIS Coordinate System

[GradientWind]

Using AutoCAD 2017, I have been using the Map tool, and am setting the Geographic location of my drawing. When I get to the list of GIS coordinate systems, I don't know which one to select. It is best to select a coordinate system local to my project location, but how do I know which coordinate system is local?

Thanks,

[Jonathan3891]

I'm assuming your working in an environmental or civil firm. If I'm correct, couldn't you ask the survey crew or manager what coordinate system they used?

[GradientWind]

Yes we are in that field. My question is more to do with the selection from AutoCAD itself. If I wanted to pull up site imagery from AutoCAD, I would like to know which GIS coordinate system I should use.

Thanks,

[john.vellek]

HI @GradientWind,

Here is an article  and another that might help you with selecting a GIS Coordinate system when placing your map.

Please select the Accept as Solution button if my post solves your issue or answers your question.

[GradientWind]

Hi John,

Thanks for the information. My question has to do with selecting the Coordinate System. Like the article says, the drop down list has many types of coordinate systems. How do I know which one to choose?

Thanks,

[john.vellek]

Hi @GradientWind,

Forgive me if I say this incorrectly as I am no expert on GIS Coordinate systems.

As the linked articles explain, the system selected is to reduce the amount of distortion in the GIS mapping you use.  Where are you obtaining your maps?:  Often times, map sources will provide the Coordinate. system used when recording the data. In my understanding (oh oh - I feel like I am in over my depth now) that using a system that is closer to the location of the data will provide less distortion and a better map projection quality.

Let me touch base with my Civil 3D and Map specialists to see if they have some basic guidelines that can help you (and me) in this process.

Please select the Accept as Solution button if my post solves your issue or answers your question.

[GradientWind]

Hi John,

What I use the Map feature for is to draw on top of the map. We need to outline the buildings from a plan/aerial view, than we take these plans and complete our analysis, or extrude the buildings upward to make a 3D model of the specific area. We don't use GIS for our work, so hence I don't know which coordinate system to choose.

I feel you are correct, from my little understanding. The choice of Coordinate System is to ensure the map imported into AutoCAD is projected correctly. Some Coordinate Systems will have a datum closer to the our location meaning the image will be correctly displayed. Any information you have on which coordinate system I should select would be helpful.

Many thanks,

[sthompson1021]

I believe that the coordinate systems at the top of the list are the closest to where you drop the marker at. At least that is how they are listed in my neck of the woods.

[wispoxy]

UTM83-17F, NAD 83

[Alfred.NESWADBA]

Hi,

@wispoxy

>> UTM83-17F, NAD 83

How do you know in which area the OP has it's project?

• NAD is only valid for North America
• UTM83-17F is only valid for a small band in US (as you can see >>>here<<<)

It also depends on the units the OP is working with, there are coordinate system in degree (not usable for CAD drawings) or metric or imperial units. The coordinate system also should be in the same units as the project is designed.

So using a coordinate system designed for Foot and draw in Meters is not the preferred method (as long as you have the choice).

- alfred -

[john.vellek]

HI @GradientWind,

My AutoCAD Civil 3D specialist offered these links that might help you.  Considering your location, the first article might be pertinent unless your projects occur elsewhere. There is no quick and easy answer as is evident by the number of responses already in this thread.

I hope these help a bit. And, as Alfred pointed out in his post, UNITS are a big deal so keep an eye on them.

Link1

Link2

Please select the Accept as Solution button if my post solves your issue or answers your question.

[wispoxy]

@Alfred.NESWADBA I was just sharing what I use, and was hoping I wouldn't have to write a full novel to be specific enough to not get thrown under a bus. Can't disagree with your statement ether:

"It also depends on the units the OP is working with, there are coordinate system in degree (not usable for CAD drawings) or metric or imperial units. The coordinate system also should be in the same units as the project is designed.

So using a coordinate system designed for Foot and draw in Meters is not the preferred method (as long as you have the choice)." -alfred

[john.vellek]

HI @GradientWind,

Did the articles (links) in my last post help at all? If not, I can try to find more resources for you.

[GradientWind]

I have not had a chance to review the online document.

I can find basic information on the history of NAD27 and NAD 83 (as you link provides). But as for other Names (not just ones in Canada) there is no information? Like CAN83-12, UPS-N, BLM-17 or CANQ27-M12-IF. These code names (not just the three I have listed, but all of them in the list), I can't Google the names and find information on them as to whether they are best suited for what I need. For someone not in GIS, I don't know how to read these Names to know if I should use them.

Many thanks,

[sthompson1021 · Accepted solution]

As I said in my first reply, the coordinate systems are listed from closest to your marker location going out. From what you described you are using the map feature for, it really doesn't make to big a difference which one you choose although I would follow Alfred's advice and choose either feet or meter.