Thanks for the reply Cliff. This question was generated by my downloading
free color air photos from the MSN/USGS Terraserver site that come down as
jpgs with .25 m (one quarter) cell or "pixel" size that are nominally
orthorectified in UTM NAD 83 and come with a .jgw file that allows
automatic registration of these images in MapInfo. These same images are
sold on other websites.
As a geologist and not a geodesist I was having a bit of trouble trying to
find out 3 things which might be of general interest to the MI list:
1. Does the NAD 83 UTM coordinate system of MapInfo reflect the HARN
corrections if present?
2. When Terraserver says these images are NAD 83 UTM does this account for
HARN corrections?
3. Are you saying that the HARN corrections are less than the .25 meter
cell size of these images anyway so the above questions are moot?
Thanks and regards
George M. Smith
At 10:29 PM 5/30/2005, you wrote:
The differences in the reference frames you cite are of concern to
geodesists and Land Surveyors that position things in the real world at the
centimeter level. MapInfo can conceivably accommodate any one of these if
your data is good enough.
You pick the data set, you make sure that everything else is in the same
reference frame and epoch, and ANY standard GIS package can accommodate it,
including MapInfo.
If you wish to transform among those high accuracy systems, use NADCON.
That is separate and apart from MapInfo.
In summary, yes MapInfo can handle it if you can.
Clifford J. Mugnier
Chief of Geodesy and
Associate Director,
CENTER FOR GEOINFORMATICS
Department of Civil Engineering
CEBA 3223A
LOUISIANA STATE UNIVERSITY
Baton Rouge, LA 70803
Voice and Facsimile: (225) 578-8536 [Academic]
Voice and Facsimile: (225) 578-4474 [Research]
======================================================
http://www.asprs.org/resources/GRIDS/
http://www.cee.lsu.edu/facultyStaff/mugnier/index.html
======================================================
Does anyone know if MapInfo for the US uses 1986 NAD 83 or the 1992 or
HARN NAD 83?
Thanks
George M. Smith
George M. Smith
GeoMax
303.440.4539
fx 303.449.0280
[EMAIL PROTECTED]
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