<html><head><style type="text/css">.style1 {font-family: "Times New Roman";}</style></head><body><div dir="ltr">Greg,<div><br></div><div>Thank you for that information. I'll put together some example code and post that shortly.</div><div><br></div><div>As far as upgrading Proj4; because we build Proj4 statically in our custom build, it's not a trivial task to upgrade versions. Also, I think there might be compatibility reasons why we've stuck with 6.3.1 up until now.</div><div><br></div><div>But if NAD83 realization transformation functionality has been expanded and improved in later versions, it might be worth it for us to upgrade. I was wondering, judging by the contents of the proj-datumgrid packages I've found online, it looks like Proj4 did not support any NAD83 realization transformations besides 1986->HARN before at least Proj4 7.0.</div><div><br></div><div>Do you happen to know if this is true or not? I'm having trouble confirming this online,</div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, Jul 15, 2024 at 11:06 AM Greg Troxel via gdal-dev <<a href="mailto:gdal-dev@lists.osgeo.org">gdal-dev@lists.osgeo.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">You didn't, as far as I can tell, post the code that is not doing what<br>
you want. Or perhaps turn that code into a small test case program.<br>
People reading that would be able to be more helpful, and the code<br>
example could help others.<br>
<br>
Proj 6.3 is quite old. I recommend you update to the latest release<br>
and the latest gridshift package before debugging further. I am not a<br>
gdal or proj maintainer, but I am packager for both, and often rant<br>
about NAD83 and WGS84 issues. In general, proj has a hard time dealing<br>
reasonably with WGS84 (which you aren't at the moment), and the<br>
transforms among the various NAD83 are complicated. I am not the least<br>
bit sure they are all in the epsg dataset.<br>
<br>
You should very likely be using projinfo, and also thinking about how<br>
you are conveying the area of applicability when setting up the<br>
transform.<br>
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</blockquote></div><br clear="all"><div><br></div><span class="gmail_signature_prefix">-- </span><br><div dir="ltr" class="gmail_signature"><div dir="ltr">David Klaus<div>Carlson Software</div></div></div>
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