Help with Geo-referenced photos and GPS
Help with Geo-referenced photos and GPS
(OP)
Guys and gals, I need your help in an aera I know nothing about.
I am running AutoCAD 2000(LDD 3 & ACAD map) and I am trying to insert aerial photos in a layer along with some GPS points from a surveyer.
I am having trouble getting the GPS "points" to overlay on the photos correctly.
I am using the same units for both; NAD 83
What I am doing is using map button, insert, (then I select the photo from the file with the coord. file in Word format)
Now, the GPS information is in an ACAD drawing already. I have tried to insert the photos into that drawing and I have tried to make the GPS "points" into a block and insert them into a new drawing with the photos already inserted.(without selecting a base point-letting ACAD do it)
Those attempts have failed. The GPS points are miles away from the area they were taken from.(according to where the photos are)
Any help would be great.
D. Rogers
I am running AutoCAD 2000(LDD 3 & ACAD map) and I am trying to insert aerial photos in a layer along with some GPS points from a surveyer.
I am having trouble getting the GPS "points" to overlay on the photos correctly.
I am using the same units for both; NAD 83
What I am doing is using map button, insert, (then I select the photo from the file with the coord. file in Word format)
Now, the GPS information is in an ACAD drawing already. I have tried to insert the photos into that drawing and I have tried to make the GPS "points" into a block and insert them into a new drawing with the photos already inserted.(without selecting a base point-letting ACAD do it)
Those attempts have failed. The GPS points are miles away from the area they were taken from.(according to where the photos are)
Any help would be great.
D. Rogers





RE: Help with Geo-referenced photos and GPS
Generally, the insert image commage on the map menu is pretty straight forward. Typically, georeferenced images are geotiffs and they usually have two files associated with them, one is .tif which is the actual image and a .tfw file which is basically a text file that assigns coordinates to the image. Both MUST have the same name prior to the file extension. Perhaps you moved or deleted this file.....
Good luck
RE: Help with Geo-referenced photos and GPS
I have the text files with the same name.
I have a feeling the problem lies in the GPS points from the surveyer. These are in an ACAD drawing already so I dont know how I should check those or re-insert them correctly.
Thanks.
RE: Help with Geo-referenced photos and GPS
I am in Delaware. We do survey work using state plane feet. Our state orthophoto inventory is in meters. You can check this by scaling the photo by 3.28083333 (U.S. survey feet in a meter).
For Map to successfully import this the first time:
1. make sure your drawing units are feet
2. Use the Image Insert in Map as you described, but be sure to select Meters for "insertion point and density" on the Source tab.
RE: Help with Geo-referenced photos and GPS
I have one more question.
Can I draw at specific coordinates? I mean, if I have a Garmin GPS unit with a waypoint in it. Can I, draw a circle with the center at that waypoint's coordinates?