contour lines don't match up with raster

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03-27-2012 04:39 PM
Michele
New Contributor III
Firstly, I apologize if I've placed this in the incorrect forum, but this was the best category I thought my question pertained to. 

I've created a raster dataset by interpolating point data using the natural neighbor function.  I also created contours from the raster data which are delineated fairly well except in one spot.  I was wondering if anyone knew why this is and if there is any way to fix this.

Thanks
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ChristopherThompson
Regular Contributor
What occurs to me is that your raster is classified so that each grouping reflects a range of values (61-70cm it appears from your graphic in the area you indicate) while the contour interval is a discrete value, it represents only one value.  Try doing an identify on the contour line and the raster cells that underly that directly, then do a identify on the cells that are at the edge of that classification group.  My guess is that the contour value maybe something like '65' the cells to the east of there are some other value.  This is simply the difference between using a discrete value versus a classified value that reflects a range of values.
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Michele
New Contributor III
Hmmm...maybe???  But I'm not so sure. I manually changed the label value to 51-60cm values, the actual raster value is "6" (which corresponds to 51-60cm label value) and the contour line is "50".  When I use the identify tool on a raster cell on either side of the contour line displays "6" (on both sides).  It's just weird that the line isn't drawn at the edge of the value like the rest of them are.  Also, I used unique value symbology.
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