My layers appear too far after defining projection

[ryannz]

Hello everyone, I have a question. I need to do some spatial adjustment on a layer importing from Shapefile. However, because the shapefile doesn't have correct Geographic Coordinate System, I used Define projection to change it to GCS WGS 1984. But when I do that and add a basemap suddenly the layer doesn't appear on the map anymore. It just disappear. If I changed the layer back to unknown GCS, then I can see it again. How can give it right projection and still be able to see it, so I can do some spatial adjustment on it.

Please help me please. This is very important.

[JessCartwright]

If it was initially projected, just to the wrong projection, then you would use Define Projection to tell ArcMap which projection it is in first before using the Project tool to change it into the desired projection.

[ryannz]

Thanks for all the replies. I will create a video clip and post a link tomorrow. That way you can tell me what I have done incorrectly.

[ScottDean]

As others have mentioned, you cannot define a projection unless you are sure you know what the projection is for the source data.  If you define it as something other than it truly is then you will have problems down the road.  Here is something that may help you.

http://support.esri.com/es/knowledgebase/techarticles/detail/24893

[ryannz]

Everyone, please check this video clip:

http://screencast.com/t/Gd7p73l1hI

The points were created in AutoCAD and saved as Shapefile.