Georegistering a JPEG image which is served over the Internet by a third party is essentially the same process as georegistering your own, local JPEG images. First of all, download a copy of the remote image by invoking it in your web browser, right clicking over it and choosing Save Image as...). Then, perform a Quick GeoRegister or a Multipoint Georegister as normal in TM GeoRegister. You can then delete the local copy of the image if you want: during the metadata registration process for remote images, you will be prompted for the remote location of the image (i.e. the URL or web address) and this information will be stored in the ECAI Clearinghouse.
MRSIDs
Georegistering a MRSID image served over the web by a third party is slightly more complex. Because you won't normally be able to download the entire MRSID image over the Internet, you will need to georegister a JPEG facsimile of the MRSID image, and provide TMGeoReg with some information about the original MRSID image.
First of all, download a JPEG facsimile of the remote MRSID by invoking the entire MRSID image in your web browser, right clicking over it and choosing Save Image as...).
Before leaving that webpage, open the HTML source code which underlies it (View > Page Source in Netscape; Edit button or View > Source in Internet Explorer).
You will need to glean three pieces of information about the MRSID image from the source code on your screen: the width (X) of the image, the height (Y) of the image, and the number of zoom levels.Generally, the information appears in the souce code in this format:
Levels: <input type=hidden name=levels value=4>
Y Value: <input type=hidden name=fullheight value=2712>
X Value: <input type=hidden name=fullwidth value=3930>
Take note of these values, making sure you have the full height and width, as several different height and width values will appear in the HTML source code.
Note: There is other information in this source code which you will need later when you register the image's metadata with the ECAI Clearinghouse. See the this help topic for details.
When saving the worldfile information, check the box marked "MrSID Facsimile" and enter the X size value, Y size value and zoom level values of the remote MRSID image into the appropriate fields.
Then press the Save button on the toolbar. TMGeoReg will create worldfile metadata in exactly the same way as it does for a local image, but modified to reflect the true properties of the remote MRSID image, rather than the JPEG you have registered in its place.
You can then delete the local copy of the image if you want: during the metadata registration process for remote images, you will be prompted for the remote location of the image (i.e. the URL or web address) and only this location information will be stored in the ECAI Clearinghouse.