Trouble Reprojecting a Raster

[JonathanSanford]

I’m trying to use the Project Raster (Data Management) tool to reproject a .tif or .IMD file from NAD_1983_UTM_Zone_13_N into NAD_1983_StatePlane_Colorado_South_FIPS_0503_Feet.

Every time I run the tool the output raster looks just like the UTM projection. The only thing that changes is the layer properties for the output raster claims it’s in the State Plane projection, yet it is identical to the UTM projection. Am I missing a step in the process here?

[DanPatterson_Retired]

Well it will look the same if it resides in the same dataframe that the source file was used from.  If a single dataset is added to a dataframe, it sets the coordinate system for the data frame.  Then you perform a projection of that layer to a different coordinate system... I may look totally different, but you won't know since it resides in the original dataframe, it gets projected-on-the-fly to the coordinate system of the dataframe.  Open a new data frame, move the projected file to it.  It may or may not look different...in your case, there was a consistent transformation of coordinates so that would not alter the shape of the file, but differences in the location relative to the central meridian in their respective coordinates systems.  To experiment with what I am talking about, do this process with an unprojected layer (GCS NAD83 for instance), project it to UTM whatever, for that area... you won't see a difference in the projected file until you either move the projected layer to a new data frame, or change the initial dataframes coordinate system to match the projected output

[JonathanSanford]

Thanks for your reply, Dan. Some of the terminology was a little above my experience level (please bear with me, I’m somewhat new to working with imagery), but I think I got the gist of what you were saying. I tried playing around with projecting the raster in a new data frame, and I’m wondering now if projecting the raster is really want I need to be doing here. Let me explain the exact problem I’m working on.

We recently purchased imagery for our service area to be loaded into ArcGIS Online for use in Collector. Before we can do that, we need the imagery to line up with parcels, roads, etc. I figured the easiest way to do that would be to just reproject the raster, but that is more complex that I originally thought.  

Below is a screen shot of the parcels in the area I am working (orange) on top of Esri’s World Imagery basemap:

 

Here is an image of the same parcels layer, this time on top of the original raster. The imagery does not align with the parcels, I assume because they are in different projections:

 

Lastly, this is an image of the parcels layer on top of the raster once it has been projected into the State Plane:

 

Looks pretty much identical to the original raster. I noticed that it did shift a little bit, but not nearly enough to be useful. Is it possible that I need to do something else besides projecting the raster? What’s the best route for getting the imagery to line up with the parcels layer?

Thanks for your help!

[DanPatterson_Retired]

In a case like that, it sounds like one of the reference layers doesn't have a defined coordinate system in which case it can't be projected on the fly.  I don't do the online stuff much but within arcmap, can you check the properties of the layers to ensure they have a defined coordinate system and what they are?  I am guessing wildly that projecting the raster isn't needed since you know what its coordinate system is.  The apparent shift could be due to a datum difference (ie NAD27 vs NAD83) or something similar.  Before you start Defining Projections or Projecting stuff, I would spend some confirming that what you have is known and defined correctly if it is.

[CodyBenkelman]

Jonathan 

ArcGIS will automatically reproject your imagery to match the current projection of your map; since your parcels line up correctly with the basemap, it appears your parcels are correct but I suspect that there is an error in the metadata that defines the projection of your imagery.  You should not need to reproject your imagery, but (if my assumption is correct), edit the projection metadata using the Define Projection tool.

Can you navigate to your imagery in ArcCatalog and right click to see Properties and let us know what it shows?  If you purchased this imagery, I would contact the source and ask them to verify the projection - but if you can't confirm it is A) incorrect and B) what to change it to, let us know and we may be able to help figure it out.  Presuming we get it right, your adjusted data should line up with the basemap as well as your vector dataset.

If you edit the projection data, be sure to make complete notes about the original metadata before you change it - or better yet, save a *.PRJ file that shows the *current* projection before you change it.  (If you don't know how, do this presuming you are using ArcMap:  create a new map, load your raster dataset, then right click in the map.  Select Data Frame Properties, Coordinate System tab, and you should see projection details in the lower window, and the projection name in the upper window.  Select the projection name in the upper window, right click, and Save As to save a *.prj file.  NOTE that this will save a file with the projection name, but if I am correct, this is the INCORRECT projection, so I would put it into a folder called something like "Original_projection_incorrect")

Cody B.

[JonathanSanford]

Hi Cody,

Here are the properties for the imagery from ArcCatalog:

There was also a text file with the imagery containing the following information:

 

I also noticed in the Data Frame Properties window under the Coordinate System tab that in the projection for all of my vector data is in a Lambert_Conformal_Conic projection, and that the projection for the raster data is set to Transver_Mercator. Could this be causing the problem?

I did not order the imagery personally, and I don't know if the person who order it specified what projection we needed. 

Thanks!

[CodyBenkelman]

Jonathan

It appears to me that your image was produced in NAD27 UTM 13, and the metadata was incorrectly written as NAD83.  In this screenshot, I created the yellow polygon in NAD83, then I used DEFINE PROJECTION to rewrite the metadata as NAD27 and reloaded the new polygon (white).  That shift appears to be pretty similar to what you're seeing in Y, although I'm not certain about X...

Note I am only guessing at this point.  You can use the DEFINE PROJECTION GP tool to change the projection for your imagery to 

NAD_1927_UTM_Zone_13N
WKID: 26713 Authority: EPSG

...and then re-load it into your map and see if it lines up with the base map and feature data.  But note if it is not pretty much perfect, then my guess is wrong and you should probably restore it to its original projection.  In either case I'd suggest you contact MapMart (It appears that's where the data came from?) to see if they can confirm...

Be sure to check the alignment at the extreme corners of your imagery - if I am correct it should be good everywhere.  If not, then hopefully MapMart can track down the correct information.

Finally note that ArcGIS does include Georeferencing tools that could be used to align this image, if you can't determine the correct projection, but using DEFINE PROJECTION would be preferable if you can be certain about what the correct projection should be.

good luck
Cody B