resuriko

Georeferencing Total Station Data - ends up looking "squished."

Discussion created by resuriko on Apr 21, 2012
Latest reply on May 4, 2012 by chrisgarrard
I'm not sure if this is the right place to post this.

Let me start by explaining the data I'm working with:

My professor has a mapping project that she's working on in Belize. We walk a transect, taking various points on our Mobile Mapper, 4 Garmin GPS units and a Total Station. The Total Station data is arbitrary and needs to be georeferenced (so it shows up in the right location along the transect). I tried linking various points that are in the TMS to ones that are taken with the Mobile Mapper, effectively trying to "move" the TMS data to overlay with the other GPS data.

The problem:

When do the usual georeferencing procedure (linking control points etc) - the TMS data ends up moving, but it appears "squished" - somewhat like an image you might open in MS paint, shrink it by the corners and make it distored - etc. The points MOVE, but they're no accurate, like GIS is stretching or squishing them for some reason.

I don't use GIS a lot, and I have never taken a class. I'm only trying to help my professor based on tutorials I can find online, and what she has taught me - but we're both stumped!

I'll try and play with the data a bit and show an example picture...but my shp files got a little corrupted and I have to fix them. I guess what I'm really looking for is just a general idea as to what would make GIS squish the data. I was told we may need to get more points to use as control points. If that's the case, we can do that this summer when we go back down to Belize. But if that's not really the issue, it could save us time in the field if anyone had an idea how to fix the problem within GIS.

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