Hi Stewart,

I have ver. 4.6; is there no hope for my jpg files?  The company I bought
them from says it cannot offer tiff.

I tried bringing the image file into a photo editor and saving it as .jpg,
and changing the extension on the world file.  The graphics came in, at
close to the same location (at least it was on the map in the same area) but
the scale was no where near the same.

Any hope?

Pam


Pam Lardear
Run River Enterprises
http://www.runriver.net
315-559-0526
"Helping you find your Way"


-----Original Message-----
From: berry_stewarttrancad [mailto:[EMAIL PROTECTED] 
Sent: Wednesday, January 12, 2005 9:51 AM
To: [email protected]
Subject: [Maptitude] Re: image files



Hi Group:

Maptitude 4.7 supports *.jpg files:

The Joint Photographers Expert Group (JPEG) file format, named after 
the committee that wrote the standard, is based on a mechanism 
designed for compressing either full-color or gray-scale images of 
natural, real-world scenes. It works well on photographs, 
naturalistic artwork, and similar material; it does not work so well 
on lettering, simple cartoons, or line drawings. JPEG handles only 
still images (there is a related standard called MPEG for motion 
pictures). Maptitude can use pictures and images stored in JPEG files 
as layers in your map.

JPEG is "lossy," meaning that the decompressed image isn't quite the 
same as the original image. JPEG is intended for compressing images 
that will be looked at by humans, because is designed to exploit 
known limitations of the human eye; you are more sensitive to small 
changes in brightness than to small changes in color.

JPEG is a less-desirable image format than some others for two 
reasons. It is slow to display, because the file needs to be reread 
(starting from the beginning) each time a new portion of the image is 
displayed. Formats such as ECW, MrSID, and TIFF are designed so that 
portions of the image can be displayed by finding and reading only a 
part of the file. Also, JPEG has a fuzzy appearance and limited 
resolution, especially for large-scale display of map and other 
images with linework and text. Formats such as ECW and MrSID provide 
increasing levels of resolution as needed (to some limit) as you zoom 
to larger scales.

To use a JPEG file in a map with other geographic layers, it must be 
accompanied by a JPEG/World (.JPW) file. This file contains 
registration information for the JPEG image, and Caliper registration 
information is added at the end of the file. The first time that you 
open a .JPG file and its .JPW file, they must be in a folder to which 
you have write access so that Maptitude can add the necessary 
registration information.

Stewart

--- In [email protected], "Pam Lardear" <[EMAIL PROTECTED]> wrote:
> I just purchase an aerial photograph that I am trying to use with my
> Maptitude.  It comes as a .jpg with a .jgw World file.  Is there 
any way to
> use this with Maptitude, or to convert it to the TIFF and TIFF 
World?
> 
>  
> 
> If not, can anyone recommend a good source for aerial photos that 
work?
> 
>  
> 
> This is from Terraserver.
> 
>  
> 
> Thanks,
> 
> Pam
> 
>  
> 
>  
> 
> Pam Lardear
> 
> Run River Enterprises
> 
> http://www.runriver.net <http://www.runriver.net/> 
> 
> 315-559-0526
> 
> "Helping you find your Way"






 
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