MrSid images: No Projection

[D__SamuelRajasekhar]

Hello All,

I have received numerous MrSid images (historic aerial photographs - geo-referenced, most probably).

When I open them in ArcMap (or ERDAS Imagine), they are not projected and without any projection information.

I tried to look for header or other files and none are present. The image information likewise yields a blank for coordinate system.

Can anyone provide some insights? Does the compression has something to do with this?

thanks,
Samuel

[JoshWhite]

If there is no coordinate information at all, then they are not georeferenced.

Many of these older aerials have the section corners and potentially other benchmarks that may help you to georeference them.

[D__SamuelRajasekhar]

Thanks.

There are TIF images delivered in the same project that are geo-referenced and display well with projection.

These MrSid images have associated text files (GCP) that indicates geo-referencing. Say 4 to 6 image coordinates & map coordinates per image.