Coordonate Systeme and Origin

[Anonymous]

Hi,

There is something I don't understand, I assign a coordonate systeme on my drawing. But how can I assigne the 0,0 of my drawing in the 0,0 or the coordinate systeme? 

If I draw a line, from 0,0, it's not on the origin of the coordinate systeme.. is it normal?

thanks!

[BrianHailey]

Assigning a coordinate system to your drawing doesn't change the basepoint of the drawing, it's still at 0,0. Assigning a coordinate system to your drawing, basically relates it to the real world. When I draw a point in the drawing, where, in the real world, is that point? 

How did you go about assigning the coordinate system? Did you go through the Civil3D settings, the Map 3D CSASSIGN command, or through the AutoCAD geolocation?

[Anonymous]

I see. But if I assign a coordonate system and I ant to put a point for example, in Paris, I willl put the coordinate of Paris, not of the 0,0 of autocad..

I assign with Edit Drawing, but how can I put a UCS of the origin of the Coordinate System?

[Anonymous]

I don't understand it, either. If I draw a line from 0,0 in Wisconsin Dane County Coordinates, it's 0,0 in both the drawing and the coordinate system. What are you using for UNITS?

[ChicagoLooper]

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@Anonymous wrote:

If I draw a line, from 0,0, it's not on the origin of the coordinate systeme.. is it normal?

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The question shouldn't be, 'is it normal?' 

The should be, 'Why do your want to draw a line that begins at 0,0 of your coordinate system grid?'  

How does a line beginning at 0,0  benefit your map? What is the purpose of that line?

[Anonymous]

I use those lines to temporarily identify where I am at in larger pictures. For example, I'm working on a water system on a certain street. I want info on only that pipe and the next block. Our water GIS drawing has all 900+ miles of pipe in it. If i draw a line from 0,0 to my area of interest, then copy/paste it into the system drawing, which is slow as heck because of all that is in it, I can immediately ID my area so I know what pipes to grab to copy into my design drawing. it's just a tool.

This example doesn't explain why 0,0 isn't 0,0. unless there are shifts, corrections, false coordinates, whatever applied, I don't see how a grid origin could *not* be 0,0.

[ChicagoLooper]

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@Anonymous wrote:

<<I don't see how a grid origin could *not* be 0,0.>>

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Just because you don't see how, doesn't mean it doesn't work that way. It works that way because that's the way the State Plane system was developed in the 1930's, and I doubt if you, or anyone else, will be able to change it. 

For example, for Washington State, there are two zones, North and South. Like all SPCS zones, both the drawing's origin and the Grid origin are both in the Pacific Ocean and not on dry land.

[ChicagoLooper]

OK.......but why draw a line from 0,0? Why not simply drawing a rectangle  around your target area? 

If both draw drawings, the GIS drawing (your term not mine) and your AutoCad drawing, are using the same coordinate system, the pasted entity, whether line or rectangle, will be geospatially accurate when pasted. 

Or even more powerful is use a query to isolate your pipes, especially if you want to isolate pipes down to the nitty-gritty, such all pipes larger than 12” diameter, made of reinforced concrete, in the Westmorland neighborhood and installed prior to 1994. 

[Anonymous]

I draw the line mainly because the entire city of several square miles of pipes looks like a plate of spaghetti. A small rectangle would be lost. A line, that could be drawn from anywhere far from 480000/850000, which is in the range of our coordinate system, to the site in question, would work - anything that stands out from the mess of pipes. The GIS drawing, as I call it, originates from our ESRI based GIS. It has no streets or other means of identifying where in the city you are - just pipes, valves, hydrants and ID text. It is a massive resource hog in Acad. Opening the dwg takes minutes, zooming/panning anywhere takes several seconds. It really helps to know exactly where to window.

Again, this has nothing to do with why 0,0 in C3D doesn't equate to 0,0 in the coordinate system, but you asked ... 🙂

[ChicagoLooper]

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@Anonymous wrote:

<<anything that stands out from the mess of pipes.>>

Then you need to change your work flow so you can avoid bringing in the mess of pipes and only bring in what you need, such as 3 square blocks within the city.

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<<The GIS drawing, as I call it, originates from our ESRI based GIS. It has no streets or other means of identifying where in the city you are - just pipes, valves, hydrants and ID text.>>

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No means of identifying where in the city? Huh? Of course it has a means to figure out where in the city. The GIS data is geospatial so you can use geography. From a brand new drawing with an assigned coordinate system, without any shapefile or AutoCad entities, you can turn on turn on Bing imagery. Your site is 3-square blocks next to the University. Draw a rectangle encompassing the target area then use that rectangle to limit the data you bring in, as opposed to bringing in the mess of pipes that takes minutes to load.  

Alternatively, you can use MAPIMPORT and create a master file of the pipe network so they'll be AutoCad polylines instead of ESRI feature data objects. Then, using a QUERY, bring in only the line work you need, such as line work that's in, touching or intersecting your rectangle.

Change your work flow and you'll be fine. Continue using your method and you're always be relegated by slow, heavy data you don't even need.

[Anonymous]

I will give it a shot! thanks for the advice.

[Anonymous]

quick question for you @ChicagoLooper : given that I have established the limits of my target area with a rectangle, would you use ADEQUERY to get the objects into my working drawing, or another method? I do need objects, not a data connection.

[ChicagoLooper]

Correct. ADEQUERY is the command. How you use that command and what you do before and during the command can make a difference. Big time difference.

There are different ways to query. The quickest way, in your case which is to isolate pipes in a three-square block area, is to use a Data Connection in combination with a QUERY. Using this method will do two things: A) limit the pipes to a 3-square block area and B) 'extract' AutoCad polylines from the ESRI line work.

Starting from a brand-new clean drawing, assign an appropriate CS, turn on Bing Hybrid imagery, change your workspace to Planning & Analysis, pan and zoom in on your target area, then draw a rectangle big enough to 'cover' your target area. Once your rectangle is drawn, turn OFF Bing Hybrid. A simple four-sided AutoCad polygon will suffice. Make it a little bigger than what you need so you'll have extra in case you need to pan or zoom out when fine tuning your map. Then use a Data Connection and connect to your shapefile.

1. Don't bring in the entire shapefile using Add to Map option. Instead, use ADD TO MAP WITH QUERY option. Image-1.
2. In the Create Query window, Locate on Map Icon=>Touching Any Part of.....Polygon=>OK. Image-2
3. On command line click 'S' for select. Your cursor will turn into a tiny square. Image-3.
4. Using your square shaped cursor, click directly on your rectangle. Then OK to complete and exit the query. Image-4. (At this point, the lag that occurs during pan and zoom functions will be minimized since you're 'limiting the data to 3 square blocks.')
5. Go to Task Pane and highlight the shapefile pipe layer then click TABLE icon. Image-5.
6. From the extreme left column of the table, use your cursor+shift key and the scroll bar, highlight ALL ROWS in the Table making sure all rows turn blue. Once they're all blue, use the MAPEXTRACTFEATUREGEOMETRY command or the equivalent icon on the ribbon which will extract AutoCad polylines from the ESRI feature data objects. (You are actually making copies of the ESRI line work and the copies will be AutoCad polylines.)  Image-6.
7. If you are asked to Continue or Cancel checkout, choose CONTINUE CHECKOUT. Image-7. You may now right click the pipe layer in the Map Task Pane and select Remove Layer. You don't need that layer anymore.

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Notes:

• Icon for mapextractfeaturegeometry is found here: Feature Edit Tab=>Modify Panel=>Icon with orange arrow and blue shapes. 
• As an alternative, you may use MAPIMPORT and bring in all pipe line work. This command will extract ALL ESRI pipes and convert them to AutoCad entities or polylines. Name and Save this drawing with the newly created polylines, then close the drawing. The query won’t work if the drawing remains open. Next, you can 'ATTACH' and QUERY from the Map Explorer Tab of Map Task Pane. Warning: This is not the same ATTACH command you use to attach an XREF, this ATTACH is different. Using the same ATTACH command as attaching an Xref is not capable of executing a query.
• Using MAPIMPORT and combining it with a query also uses a rectangle to limit the AutoCad polylines you bring in. This type of query is performed through the Map Explorer Tab and not the Data Connect Palette.
• Use the MapImport procedure to create a Masterfile of pipes. Since you have SAVED this Masterfile, you may continue to run future queries from it. However, if the original shapefile is updated by the City, you’ll need to update your Masterfile too so be informed using this method requires you to maintain the masterfile. Be sure to 'Create Object Data' during the MapImport procedure. If no object data is created, you won't be able to run any queries because THE OBJECT DATA is what drives your query.

[Anonymous]

thank you! great workflow explanation.

We've got a dwg exported from Arc with everything in it, so I am thinking that querying this dwg with geographical limits and having it Draw the results of the query will get it for me. I have your excellent post to refer to as well!

[jeff_rivers]

Yeah, thanks for posting this.  I often gather GIS data to start a project before my topo survey is done, and I've been doing it a different, slightly more cumbersome way.  I'm saving this to try on the next project.  

[lynn_zhang]

Hello @Anonymous ,

Just checking to see if your problem has been solved. Did the response from our experts above help answer your questions? If yes, please click on the "Accept as Solution" button in their reply so this helps other users in the community find the solution too. Thanks!

[timpy6]

ChicagoLooper

You sound like you know what you're talking about. I have a question or two. In that screenshot you created of the north zone of the SPCS I see the two magenta-colored origins in the ocean. I am wondering whether the origin of the drawing (lowest and left-most origin) references the origin of the coordinate system north zone, or does it represent the false northing/ false easting origin of the coordinate system. How far apart in feet are the actual origin and the false northing/ false easting?

If the drawing origin does not represent the SPCS origin then what does the origin of the Civil 3D file represent?

Also, when linking to Revit, how do you deal with the geometry being too far away from the origin point for Revit to handle? Do you delete the origin symbol so that only the main geometry is shown? And what is that red star coordinate you often see in survey drawings? Does it represent away important point, or just a Bing map rough location?

Thanks