topic Re: I have a coordinate system projection problem ...part 2 in Data Management Questions

I have a coordinate system projection problem ...part 2

DanRose — Tue, 22 Nov 2016 20:33:04 GMT

I have a similar issue, wondering if you can help: A new(er) GIS map doc, the data frame coordinate system and all data was captured (GPS) and drawn in NAD_1983_UTM_Zone_15N (matching the ESRI World Imagery). All datasets, aerials, parcels, street centerlines, etc. match, no issues there.

UTM Zone 15N is in meters, I am displaying my units in feet. What I'm not understanding is that, for instance, I have a sewer main that measures (in reality and in my GIS) at ~533'; it displays (in the main's SHAPE_length field) as only 165. I can do the math, knowing that this is given to me in meters, approx. 1/3 of the actual distance.

No matter what I do, I cannot get the map to display and measure everything in feet, representing the reality of field measurements. I've set all my datasets, aerials, parcels, and map document into my preferred coordinate system (NAD_1983 StatePlane Kansas South FIPS 1502) (which is in US Feet), then everything gets even more screwy - a mile section only measures about 1600 map units...

Ideas?

Re: I have a coordinate system projection problem ...part 2

DanPatterson_Retired — Tue, 22 Nov 2016 21:56:14 GMT

coincidently, 1 mile is about 1609 meters!

Re: I have a coordinate system projection problem ...part 2

DanRose — Tue, 22 Nov 2016 21:59:45 GMT

Yep - right now, I have a calculated field adjacent to my SHAPE_length field that multiplies the drawn length by .3048, giving my necessary foot measurement, obviously a static field until I calculate it again... I'd rather not have a workaround, I'd rather have feet = feet.

Re: I have a coordinate system projection problem ...part 2

DanRose — Tue, 22 Nov 2016 22:01:24 GMT

Oops, I meant that I calculated the SHAPE_length field by 3.28084 to get my feet.

Re: I have a coordinate system projection problem ...part 2

DanPatterson_Retired — Tue, 22 Nov 2016 22:02:43 GMT

that leaves you projecting the data into a coordinate system whose native units are in feet, which you seem to have identified. Is there a reason you haven't done this?

Re: I have a coordinate system projection problem ...part 2

DanRose — Tue, 22 Nov 2016 22:08:48 GMT

But therein lies my issue - When I realized my meters vs feet issue, I did project all my data into my preferred CS, NAD_1983 StatePlane Kansas South FIPS 1502. Everything is in feet - map units, display units but the actual distances remain static in their original state - 165 remains 165, it does not get reprojected to the ~254.2 feet as I had hoped. I'd assumed it would have 'stretched' everything to where it should be on the earth, but it did not... I returned everything to the NAD_1983_UTM_Zone_15N projection when I hit that wall.

Re: I have a coordinate system projection problem ...part 2

DanPatterson_Retired — Tue, 22 Nov 2016 22:21:04 GMT

if the distance units are in a table then they would remain the same unless recalculated. If the calculations were based on the geometry field (Shape) and housed in a geodatabase, then Shape_Length would have been recalculated, but not in shapefiles or other attribute fields. And of course, this assumes that the Project tool was used, since Define Projection does nothing good if a coordinate system were already defined

Re: I have a coordinate system projection problem ...part 2

DanPatterson_Retired — Wed, 23 Nov 2016 16:43:20 GMT

This question has been branched

Re: I have a coordinate system projection problem ...part 2

DanRose — Wed, 23 Nov 2016 16:47:49 GMT

I'm not sure what happened with the post...

Okay, new day, fresh mind.

I'm not expecting my static and calculated length field to change, only the Shape_length field; I'm also expecting to see the actual measured distance of the sewer main to 'stretch' so that it not only measures its actual field length, it is identified as such in the Shape_length field. I just switched all data and map document to my necessary CS, and same thing - it measures 164.9 map units, and identifies in the Shape_length field as 164.9 map units. It should be 541.1 feet. Both my map units and display units are set to feet.

Re: I have a coordinate system projection problem ...part 2

NeilAyres — Wed, 23 Nov 2016 19:00:32 GMT

What do you mean by "switched"?

You need to really see the actual coordinate system of the data.

Do this in ArcCatalog rather than ArcMap. I think you are getting confused with the ArcMap dataframe, which can have its own coord sys, vs the layer in the map, which can have their own entirely different coord sys.

Right click on the actual data and view the properties.

I suspect that your data is still in a metres based system. To get it to feet, use the Project_management tool.

Re: I have a coordinate system projection problem ...part 2

DanRose — Wed, 23 Nov 2016 19:55:44 GMT

Previously, I was changing each dataset/raster to the same coordinate system by going through properties, XY Coordinate System. This was not working, kept everything looking like they were in feet, but still displayed the same meter dimensions.

In the last hour or so, I changed all coordinate systems (using the Project tool in Catalog) to the one I want, which is in feet. I brought all my newly-projected feature classes, etc. into a blank .mxd, and have the same outcome as before.

The same main still measures 165 units, it did not get reprojected to the ~254.2 feet as I needed it to. The aerial, the .tif image in the background, and all feature classes are in the same CS, and verified that the data frame in the .mxd is in the same CS.

CS of sewer dataset/feature classes after Project tool was run:

CS in the data frame from new .mxd after bringing in newly-projected feature classes:

Map units in data frame (not manipulated):

Re: I have a coordinate system projection problem ...part 2

DanPatterson_Retired — Wed, 23 Nov 2016 20:10:42 GMT

You keep on using the word 'changed' in reference to coordinate systems.

So in order for Neil and I to fully understand... when we say to 'Project' the data, we mean use the Project tool in ArcToolbox's Data Management tools (skip catalog...it is gone in Pro anyway).

This produces a brand new file (as you know... but this is for the benefit of others too).

It would be very wise at this point to put it into a new geodatabase if that is what you use, or to a shapefile. Choice is yours, as long as it is not in with other stuff and fluff that might have an impact on the coordinate system and/or its interpretation. Projection-on-the-fly is what should be avoided until you are sure that you have a clean file.

Assuming that you have a clean, isolated, truly projected new file... this can be added to a new project without any other stuff. It will set the coordinate system of the data frame. Examine the coordinates on screen, and those in the properties of both the file and the data frame.

Any static fields containing geometry information need to be recalculated of course. Shape_Length etc should be in feet.

What does the above produce? If everything is fine, then you can mix other data into the project, just not before.

Re: I have a coordinate system projection problem ...part 2

DanRose — Wed, 23 Nov 2016 20:35:55 GMT

By 'change', I mean, I previously (in Catalog) had right-clicked on the dataset I needed to re-project, went to Properties, XY Coordinate System tab, and changed my coordinate system from NAD_1983_UTM_Zone_15N to the NAD 1983 StatePlane Kansas South FIPS 1502 (US Feet) coordinate system by simply clicking the one I wanted in my favorites. That yielded no change except I then had feet as my map units but without the correct measurements.

The last time tried the re-projection (a couple hours ago), I used the Project tool in the Data Management Toolset (through Catalog but using Toolbox); I was able to drag and drop the entire dataset in the interface (except for the ones that had an existing geometric network, had to delete that before I could do this). It created a new dataset, e.g. the new dataset named SanitarySewer_Project, and all feature classes inside were given the added name of _1 at the end. There is a chance I'd re-projected my datasets after I'd already 'changed' their XY Coordinate system manually through the dataset's properties... may have been my issue earlier.

I did as directed above: created a test.gdb, re-projected the same SanitarySewer dataset to the necessary CS, put it in the new test.gdb, inserted the feature classes into a new .mxd and same outcome - now it does have the reprojected dimensions/lengths in feet. Do you think I had something corrupted?

The issue now for me is to re-project everything... I was using Esri's LGIM .gdb setup - and there are a LOT of datasets/feature classes... so eventually, I'll have to re-project all my datasets in this way, to ensure everything is up to speed...

Re: I have a coordinate system projection problem ...part 2

DanPatterson_Retired — Wed, 23 Nov 2016 20:53:01 GMT

I suspect a 'define' occured along the way, instead of a 'project'. This is where shapefiles can come in handy... if they don't have a *.prj file to define its coordinate system, you can be sure that the units are the units. Your numbers seemed metric, which means they were metric and not converted to non-metric. I never trust what something looks like... I only trust what it is. I would proceed cautiously until you are sure that you have the data in the coordinates you want. A much simpler option... join the metric world but that is a different story.

Re: I have a coordinate system projection problem ...part 2

DanRose — Wed, 23 Nov 2016 21:04:01 GMT

I wish the US would have adopted the metric system in the first place.... Anyway, thank you for your help, and I agree about shapefiles and the .prj files - it's obvious how things are when you look at them.

Re: I have a coordinate system projection problem ...part 2

DanRose — Wed, 23 Nov 2016 21:16:42 GMT

Thank you very much for your help!