topic Re: TRANSFORMATIONS AND PROJECTIONS in Data Management Questions

TRANSFORMATIONS AND PROJECTIONS

ChuckTurlington — Thu, 23 Mar 2017 15:55:34 GMT

Hello,

I am using ArcMap 10.3.

I selected the Projections and Transformations under Data Management Tools to change a NAD83 state plane coordinate to the WGS84 coordinate system. I filled-in the Output coordinate system and then the under the Z Coordinate System tab selected WGS 1984. Under the Environments tab I selected Z Values "same as input". I thought ArcMap would have created the new data to a vertical metric unit but the new data still has the US feet value. I noticed a past post states that only ArcMap 10.4 has the vertical projection capability. If this is the case, what is the "Z Coordinate System" tab for and is it possible to get my vertical elevation values projected from us feet to meters ?

Re: TRANSFORMATIONS AND PROJECTIONS

DanPatterson_Retired — Thu, 23 Mar 2017 17:35:53 GMT

There is the vertical datum and then in the reference for the project tool which notes the caveat.

To perform a vertical transformation, check the optional Vertical parameter on the dialog. By default, the Vertical parameter is disabled and is only enabled when the input and output coordinate systems have Vertical Coordinate System, and the input feature class coordinates have Z values. Also, additional data (Coordinate Systems Data) setup needs to be installed on the system

Re: TRANSFORMATIONS AND PROJECTIONS

ChuckTurlington — Thu, 23 Mar 2017 18:44:31 GMT

Dan,

I am not getting the Vertical Parameter button. Below is a screen capture of my project dialog for reference. Perhaps I am missing something or do not have the correct version of ArcMap ?

Re: TRANSFORMATIONS AND PROJECTIONS

DanPatterson_Retired — Thu, 23 Mar 2017 21:57:56 GMT

as it says in the quote, they are both the same, so you shouldn't see it at all... and you should really scroll down further in the dialog to make sure you see everything just in case...

Re: TRANSFORMATIONS AND PROJECTIONS

ChuckTurlington — Fri, 24 Mar 2017 12:17:48 GMT

Dan,

Ok, if I understand, my project tab "Z Coordinate System" found when populate Output Coordinate System (see screen shot below), is the same as the "Vertical Parameter Button" you are referring ? If I am correct, my elevation values are not changing from feet to meters. I have an elevation, for example of 25.36', that value persists after the transformation (SC Nad83 Intl ft to WGS84 m). What else am I likely missing ?

Re: TRANSFORMATIONS AND PROJECTIONS

DanPatterson_Retired — Fri, 24 Mar 2017 18:40:49 GMT

this seems to be an event layer and not a z-enabled featureclass, so all bets are off. Values in a field/table won't be updated in any event. I would make a featureclass from it first before worrying about projecting.

Re: TRANSFORMATIONS AND PROJECTIONS

ChuckTurlington — Sat, 25 Mar 2017 11:23:19 GMT

Dan,

In arc catalog I created a file database, then imported my points into the database as a feature class. Then I ensured the feature class had a Z coordinate to start with (NAVD88). Then I performed the transformation/projection from NAD83 Intl Feet to WGS84 meters. The XY appeared to change properly to WGS84 but the Z values were still showing feet values. What am I likely doing wrong if I want to get meters as my Z values, assuming it is possible?

Re: TRANSFORMATIONS AND PROJECTIONS

DanPatterson_Retired — Sat, 25 Mar 2017 12:45:56 GMT

This is the only thing I can find for 3d features http://desktop.arcgis.com/en/arcmap/latest/tools/data-management-toolbox/adjust-3d-z.htm and again, it won't change z values in a table, those have to be done via a field calculator or other means

Re: TRANSFORMATIONS AND PROJECTIONS

ChuckTurlington — Sat, 25 Mar 2017 13:07:31 GMT

Dan,

Thanks for that feedback. So if I understand correctly, the actual units will not update, but the Z-Coordinate I selected will update which proves to be the case per my example project. If I "transform from a state plane system such as NAD83, to a geographic system such as wgs84, that involves both a transformation and a projection. Am I correct to assume that is the case ?

Re: TRANSFORMATIONS AND PROJECTIONS

DanPatterson_Retired — Sat, 25 Mar 2017 13:14:27 GMT

check your layer in Properties and see if if hasZ is True if it doesn't then your coordinates were 2D otherwise 3D and you would want them adjusted

Re: TRANSFORMATIONS AND PROJECTIONS

ChuckTurlington — Sat, 25 Mar 2017 13:35:33 GMT

Dan,

Yes, I believe per the screen shot below, that the Z-Values are true. If I understand, those are turned on or off using the Environments tab in the Transformation of Project, set as "Same as Input". Is my understanding correct?

Re: TRANSFORMATIONS AND PROJECTIONS

DanPatterson_Retired — Sat, 25 Mar 2017 19:10:41 GMT

so that leaves you with the adjust 3dz in my previous link, to see if that works

Re: TRANSFORMATIONS AND PROJECTIONS

ChuckTurlington — Sat, 25 Mar 2017 20:12:21 GMT

Dan,

The example involves python programming which I am not familiar, unfortunately. I did try to copy and paste the lines of code into the python window but got an error on line 1. But if the transformation/projection is complete in every other way, it is just a matter of converting the Z units to meters in excel, if I am understanding correctly.

Re: TRANSFORMATIONS AND PROJECTIONS

DanPatterson_Retired — Sat, 25 Mar 2017 20:48:45 GMT

This link is the one I was referring to. For the stuff in a table, then just add a numeric column and do the conversion directly (0.3048 -ish meters per foot refer... US foot is only marginally different)

Re: TRANSFORMATIONS AND PROJECTIONS

ChuckTurlington — Sat, 25 Mar 2017 22:17:32 GMT

Dan,

I see what you are saying. I selected in Arc Toolbox->Data Management Tools->Feature Class->Features->Adjust 3D Z. I did not see an obvious change but did get a successful response that the adjustment was made. Since I am working with points in attribute tables, I think you said the above process will not work for tables but I can use the Field Calculator to calculate the metric units in a new or un-used column of the attribute table. Please confirm if I am now understanding or if there is still some part I may be missing.

Re: TRANSFORMATIONS AND PROJECTIONS

DanPatterson_Retired — Sat, 25 Mar 2017 22:21:58 GMT

Yes... 0.3048 meters = 1 foot as in the link

Re: TRANSFORMATIONS AND PROJECTIONS

ChuckTurlington — Sat, 25 Mar 2017 22:28:36 GMT

Yes, thank you, I used Field4*0.3048 which gave the correct results. I suppose if I had linework that I needed to adjust the Z value for, then the Adjust 3D Z method is the preferred way ?

Re: TRANSFORMATIONS AND PROJECTIONS

DanPatterson_Retired — Sun, 26 Mar 2017 17:30:07 GMT

Give it a try for confirmation.

Re: TRANSFORMATIONS AND PROJECTIONS

ChuckTurlington — Sun, 26 Mar 2017 18:12:35 GMT

Dan,

Yes indeed, thanks for that feedback. The 3d polyline was adjusted in its Z value using the Adjust 3DZ function. However, the change was not obvious in ArcMap. I did not see in the attribute table or the properties of the object in ArcMap, having different units or Z values. But the Z value change was observable in CAD. Is it possible to confirm the change in ArcMap ?

Re: TRANSFORMATIONS AND PROJECTIONS

DanPatterson_Retired — Sun, 26 Mar 2017 20:11:32 GMT

the attributes table won't change if the values are represented in the table. The only things that get updated in a featureclass table is when they are in a geodatabase and that would be shape_area and shape_length. If it isn't in a geodatabase,then nothing gets changed