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Guest Larrycx

TerraServer wrong location?

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Hi all, In my project to add Crawford Reservoir to my home airport's (99V)area I went to Terra Server to get its photo shot and coordinates.I live here and know for sure the reservoir is about 1 1/2 to 2 miles SSE if the airport. The offical and FS location of 99V is N38* 42.25 W107* 38.62. Also the FS terrain has a gulch running through where I will place the reservoir by observation which is slightly W of its real location. Terra Server photo shows the pond at about 38.2155N and 107.7173W. Now that is well W of 99V. I wound up placing the pond over the gulch where it has a dam (per the FS2004 terrain) and it looks somewhat W of its real observed location by just a bit in FS2004. Am I reading the Terra server cooridinates wrong or interpreting them wrong? Has anyone else observed such a situation? There is a BIG difference between 107* 42.25 and 107.78601 as seen in slew mode. The Terra Server also gives 107W 49' 21" from my interpolation of the grid. Not a big deal but if I'm comparing apples to oranges I need to know..Larry Costa

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LarryThe DOQ's are referenced to the North American Datum of 1983 and use the Universal Transverse Mercator projection. FS used a Geodetic or Geographic projection to the WGS 84 geoid.Apples to OrangesDo an advanced search on the scenery design forum using reproject as a keyword...you'll find information from Holger Sandmann which teaches lots about reprojection.Bob Bernstein

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Hi Bob, Thanks. I was pretty sure that I would find I was apples to oranges. Now that I have poked into a few of the hits on the reproject search I'm finding its not at all simple. I took an easy out on the reservoir by using the sectional chart for the relatively course lat, long. I found I had to move one FS area to the east. The lake looks right there. Now I need to learn about VXPs so I can place a shoreline. I will start with LWMdraw and refine code as needed.Larry:*

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