Data Import - Data invalid spatial refrence

[arch.ahmed.hamdy]

Hi all,

I am still trying to learn Infra-works,anyways I managed to work on it but there is an annoying massage that pops up every time  I import any shp file.

Can anyone please explain what does it mean ?, i have been trying to figure it out but with no luck - i guess it has to do with the coordinates ! 

and my second question what is the best coordinate system to use ?  or i just select the area of interest from the model builder and that's it ? 

[Alfred.NESWADBA · Accepted solution]

Hi,

>> i guess it has to do with the coordinates

Correct. Coordinate systems are used to have a 2D-plane based X- and Y-coordinates from the surface of the earth known that the earth is not flat.

So points for different regions on the earth are described by X-value, Y-value PLUS a coordinate system in which that coordinates are valid. A point 1000,1000 in a SHP does not help you to know where it is on the world, it can be in Austria or Australia .... therefor you need to know the coordinate system for that coordinate to know where on the world is that specific point. (there are a lot of sites describing coordinate systems).

For SHP-files that means you either use the dialog to give Infraworks the info about the coordinate system of the SHP-dataset, or (in case the creator of the SHP has already assigned a coordinate system) Infrworks takes the PRJ-file (which is stored parallel to the SHP-file with the same filename, but PRJ as extension) to get the info about the SHP's coordinate system.

The message you get now is the coordinates of your Infraworks project does not fit to the coordinates from your new SHP-dataset, comparable to having an Infraworks project for Austria's Alps and trying to add points from Australians coast area of Sydney.

You have to check the source data and the coordinate systems of that source data, so that they are valid for the same region of the earth.

>> what is the best coordinate system to use

No one can tell you what is the best coordinate system you have to use as we don't know where your project is on the earth.

Generally I use the coordinate system that fits best to my region and I have the most data for (so getting less conflicts with transformation tolerances).

HTH, - alfred -

[BrianHailey · Accepted solution]

As far as which coordinate system to use, I would recommend not setting a coordinate system and letting InfraWorks default to Latitude and Longitude.The nice thing about this is it's valid over the entire globe and all well defined coordinate systems will be able to transform from and to it.

If you need to see the coordinates in your model in a specific coordinate system, you can change the User Coordinate System (UCS) in the Model Properties.

[arch.ahmed.hamdy]

Thanks Alfred - much appreciated.

[arch.ahmed.hamdy]

Thanks brain,

I am actually a landscape architect , I just wanted to know what is the best coordinate system from a best practice point of view – I might stick with that system till I get instructed from the civil guys in our project to use something else. 

[BrianHailey]

I don't see any reason to adjust set the database coordinate system. Once the database coordinate system is set, you can't adjust it.

The user coordinate system, on the other hand, can be adjust as much and as often as you like, just make sure your model is within the limits of the coordinate system you set.

[Alfred.NESWADBA]

Hi,

>> I don't see any reason to adjust set the database coordinate system

Whenever you do projects in Civil 3D I guess you don't work in LL, you use a local coordinate system to have a best accuracy of coordinates and to have only a minimum of transformations of data (as every transformation between different coordinate systems has some inaccuracy).

As long a project stays in Infraworks ... LL is ok

But whenever you do (multiple) data exchanges between Infraworks and Civil 3D (forth and back multiple times) you can reduce the number of coordinate transformations when you use the same coordinate system in your AIW-project as in your Civil 3D project.

Am I wrong?

- alfred -

[arch.ahmed.hamdy]

let me test it

[BrianHailey]

First, Autodesk doesn't seem to think this is an issue. If they perceived it as an issue, they would give us the ability to set the database coordinate system when we create a model using Model builder.

Second, I can't draw two roads that are parallel in InfraWorks let alone anything with any sort of accuracy at all. Why would you be worried about data being taken back and forth between InfraWorks and Civil 3D losing accuracy when the accuracy within InfraWorks doesn't exist? If you change something in InfraWorks and then take it back to Civil 3D, you've lost accuracy even if there is no coordinate transformation data lose. If you haven't changed it in InfraWorks, just use the data that was originally in Civil 3D.

[Alfred.NESWADBA]

Hi,

>> First, Autodesk doesn't seem to think this is an issue. If they perceived it as an issue, they would have [...]

Sorry, not a proof at all 😉

(otherwise they would have given us a lot of bug fixings ;)))) )

>> Second, I can't draw two roads that are parallel in InfraWorks

Does not have anything to do with parallel, it's enough to get troubles when using road alignments with tangent-spiral-arc-spiral-tangent in case the transformation kills that types of geometry or points based on that calculations are "too tolerant" in terms of a geodatic exact coordinate.

Just done a short check ... Infraworks project LL84 ==> created an aligment: length = 1246.616m ==> imported it into Civil 3D (local coordinate system) ==> alignment length now is 1246.729m ... and that was just a simple small sample.

Using Infraworks as product for concepts, then I agree that such small differences are ok as it's more a global visual impression. But the more close you are on detail planing you'll get more work to work around that differences.

Anyway, thanks for your input, it made me thinking 😉 .... I'll do some more tests with that!

- alfred -

[BrianHailey]

---

@Alfred.NESWADBA wrote:

Infraworks project LL84 ==> created an aligment: length = 1246.616m ==> imported it into Civil 3D (local coordinate system) ==> alignment length now is 1246.729m ... and that was just a simple small sample.

Anyway, thanks for your input, it made me thinking 😉 .... I'll do some more tests with that!

- alfred -

---

Within InfraWorks, can you draw an alignment that is exactly 1246.616 meters long in a specific direction? No (at least not that I'm aware of). InfraWorks has extremely high precision but extremely low accuracy. Until InfraWorks allows us to create geometry accurately, in my opinion this is a moot point.

The transformation from InfraWorks to Civil 3D is not perfect (due to coordinate system transformations) but you can't create geometry within InfraWorks to a degree of accuracy where that error becomes an issue.

"Where did you draw the road in InfraWorks?"

"From about there to about there."

"When it comes into Civil 3D, where does it end up?"

"From about there to about there."

[fcernst]

...Second, I can't draw two roads that are parallel in InfraWorks let alone anything with any sort of accuracy at all.

After testing for a couple weeks, there's no way this is to be considered Preliminary Engineering Design capable software to be used in conjunction with Civil 3D as it it being advertised by the product managers on the webcasts and product literature.

At it's current state, this is spatially rough Conceptual software pertaining to engineering requirements and needs.  

The Preliminary Engineering Design mode for Infraworks/Civil 3D interaction needs to be implemented as discussed here:

https://forums.autodesk.com/t5/autocad-civil-3d-ideas/infraworks-workspace/idi-p/7027617

[longislandengineeringllc]

I am new to Infraworks, but not new to C3D.  I have a C3D model in known County Coordinate system.  I set Infraworks to same system and still get same error as original poster showed.

Does anyone have more info on this error?  

I am trying to show existing terrain from model builder and my proposed grading (from C3D) in Infraworks.  So far I have failed.

Thanks!

[elliott.rosenfeld]

Hi,

Give this a try -- when you bring in data from Civil 3D, keep the InfraWorks coordinate system set the default LL84 from Model Builder, but make sure to specify the source coordinate system of the C3D data in the Data Source Configuration dialog. http://help.autodesk.com/view/INFMDR/ENU/?guid=GUID-ADC0B758-7054-4A4F-A30D-46F0DA6901E8

Thanks, let us know if that works!

best,

Elliott

[Ahmed.Hamdy.Ahmed]

Yup it worked!!

[longislandengineeringllc]

That did not help.  When I am in the Geo Location Tab.  The "Coordinate System" is populated with the C3D coordinate system.  The boxes under "Position" are grayed out and I can't change them.  

The link really didn't have any steps for me to try anything new.  It just showed the location of the Geo Location tab.  Information there is correct in my Infraworks model.

Infraworks is not displaying any surface I bring in for this project.  

I have a C3D design that I would like to show graphically to local landowners.  My grading contours will not mean anything to them.  I felt that Infraworks might be a good fit.

Anything else I can try?

Thank you

[longislandengineeringllc]

So Infraworks does not like more than one surface in a model at a time?!   If I start a new blank Infraworks project I am able to import a surface from C3D with no problem.  If I try to import the same surface in my area of interest, big problem.  Even if I try to import existing and proposed surface from C3D into same Infraworks project that is a fail.

So maybe my question is better worded.  How do I use Infraworks to handle multiple surfaces in a single project?

Thank you!

[longislandengineeringllc]

Here is what I learned.  Infraworks was indeed working correctly.  Even though I was getting the coordinate system warning message.  What I didn't know was happening is that Infraworks used the surface I imported from C3D to overwrite the existing surface.  I thought I would see two surfaces.  The existing with the aerial image draped on it and the second would be the proposed surface laying above or below the existing depending on the location.  Infraworks basically merged the two surfaces and kept the aerial draped on the new combined surface.

For me to visually show existing and proposed to clients I created a scenario.  The original is the "master" and then I create a proposed scenario and that had the proposed grading imported.

[Mohamed.E.Salem]

I have the same problem when transfer alignment or roads from civil to infrawork 

[Ahmed.Hamdy.Ahmed]

Check the Civil 3D coordinates...make sure they are the same..