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FEMA World-png Files help?

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j-t-strickland
(@j-t-strickland)
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I was pleased to see that there was a *.pgw file in the zip file when I downloaded a flood map today. However, when I inserted it in my drawing, which is in Al West SPC US survey feet, it wound up somewhere in Tennessee. It appears they are in meters.
Can anyone tell me what I should edit it to, to get it to work in feet? It is no doubt a function of the meter. I really appreciate any help in advance, and there are probably others who would benefit from the answer, also.
The file reads:

0.7620000007772400007927848008
0
0
-0.7620000007772400007927848008
394063.1
3818629.8423726


 
Posted : October 27, 2014 3:59 pm
mkennedy
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The world file contains the transformation parameters to georeference a raster from its raw 'cell' values into a coordinate reference system.

Values 1 and 4 are the cell size in meters (4 is negative because the raster is actually written upside down in the file). Values 5 and 6 are the origin point of the raster, also in meters. So you should be able to multiply all values by 3937/1200 to convert the georeferencing information to a US survey feet-based CRS.

Melita


 
Posted : October 27, 2014 4:20 pm
sergeant-schultz
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If using ACAD: insert it into drawing using world file as provided. At the command line type: scale, then select image, then base point = 0,0 - then scale factor 3937/1200.


 
Posted : October 28, 2014 4:43 am