Hello Users; I have a coordinate system projection problem

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08-25-2016 04:01 PM
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New Contributor II

I have a points feature set in projection NAD_1983_StatePlane_Nevada_West_FIPS_2703_feet. GCS is North_American_1983. The Data Frame is the same. I have added in another points feature set that is in projection NAD_1983_UTM_Zone_11N. GCS is North American_1983. When running define projection on the second set into NAD_1983_Stateplane_Nevada_West_FIPS_2703_feet, the data adjusts but is still 2 million feet away from the first set. Both now are in GCS_North_America_1983, both are projection NAD_1983_Stateplane_Nevada_West_FIPS_2703_feet and extents show both are in feet. What is going on? I have poured through Lining Up The Data book and am at a loss here.

Dave

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MVP Esteemed Contributor

Define Projection tells something what it is... it is only used when a file has no coordinate system, or it was 'defined' wrong.

On the other hand, the Project tool takes something in one coordinate system and produces a new something that is in the desired coordinate system.

You didn't use Define when you wanted Project did you?

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New Contributor II

Thanks Dan; For the prompt reply. The reason I tried the define projection option was that project just did not do anything. I tried it again after your suggestion. And the data set just doesn't move. It does create a new dataset on a separate layer, but it overlies the original exactly.   ?????    The data set did move with a define projection, but is still way off. I am wondering about this data set.      Thanks again; Dave

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MVP Esteemed Contributor

Do note... the first layer that you add to a data frame, sets the coordinate system of the data frame.

Any subsequent data which has a defined coordinate system gets reprojected on-the-fly to the coordinate system of the data frame.

Putting these together... If you project a file in the same data frame that it was in, it will not budge... nothing, it will look the same.

Open a new dataframe and drag the recently projected file into it ... remember, it is now the first in... it will set the coordinate system of that dataframe, and I bet it will look different.

Reexamine your steps in light of these comments.

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New Contributor II

Thanks Dan; Again. After working with the dataset a number of times, I can only conclude it was a bad data set. I found another version of the same shapefile and dataset and it pulls in right where it should. That and performing a GCS transformation on some others that weren't quite lining up correctly took care of the issues - for now. On to more data!

Thanks;

Dave

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MVP Esteemed Contributor

Well... you got me thinking about the whole project/define thing... so maybe you will find this amusing/useful

/blogs/dan_patterson/2016/08/29/define-projection-vs-project-a-visual-guide 

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New Contributor II

Good link Dan; And that led me to a bunch of other informative links about Geographic and Projected coordinate systems, and then on to custom symbology, and layout tutorials. Good stuff.   Dave

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