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I have the block group files from the Census TIGER dataset, and am trying to line them up with some GIS Data from HUD.

When I load them both into ArcGIS, I see that the files do not quite align, when they should:

enter image description here

Using this site (http://prj2epsg.org/search), I discovered that the TIGER files use the NAD83 GCS, while the HUD files use the WGS 84 GCS.

Assuming the different coordinate systems was the cause of the misalignment, I attempted to use the Project tool in ArcToolbox to project the TIGER files to the WGS 84. However, after doing so, and loading in the newly created layer, I end up with the exact same picture as above, even though both layers are now in WGS 84.

I'm a little lost on what to do now.


As requested, I am including screenshots showing the projection process.

Selecting Projection Tool

Choosing WGS84

Final Step Before Projection

  • Can you provide a screen shot of the step(s) you took to change the coordinate system of your shapefile – whyzar Nov 9 '16 at 17:08
  • @whyzar I just edited the post to include the screenshots. Let me know if there's any more information I can provide – ekbarber Nov 9 '16 at 17:23
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    Make sure that the data frame's coordinate system is WGS84 when comparing the reprojected data to the HUD data. What's the actual offset? I compared the HUD geodatabase (it actually uses EPSG::3857 AKA web Mercator) to an Esri topographic basemap and it lined up pretty good. – mkennedy Nov 9 '16 at 18:56
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I believe I found the cause. For some reason I don't understand, the TIGER files from 2015 are slightly different from the TIGER files released in 2016. I was comparing the 2016 TIGER files to the 2016 HUD files, but after some trial and error, I discovered that I had to use the 2015 TIGER files with the 2016 HUD files, and then everything lined up.

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