I'm trying to insert a USGS Quad Map from their website into a drawing that is set up for NAD83 Pennsylvania South, US feet. Seems the drawing may be in meters based on the TFW file and in NAD27. I am told you have to start a new drawing with the coordinate system for the image using the coordinate system library. So, I use NAD 27 meters zone 17 and save as a separate drawing for the image itself. From there' I'm stuck. I'm using CARLSON civil suite and the image loads using "place image by world file" but not in the correct location and needs scaled by 3.2808 to get correct size. Anybody have any suggestions other than manually scaling, rotating, and moving?
Global mapper is a tool that can be used to reproject the image file. It is well worth the cost, and is quite powerful.
The image files I use a lot are in meters. I use a .jpw file to make the conversion to SP US Ft. to get them to project correctly in TBC. Sample below
1.69873
0.000000000000000
0.000000000000000
-1.6987311053984
539418.6570000000000000
855151.37580000000000000
Maybe something similar? Dunno.
It will probably take more than just a scale conversion. If the map is in NAD 27 zone 17, meters that would be UTMs, not State Plane. You'll need to convert the the UTMs to NAD 27 lat/long then transform those to NAD 83 lat/long and finally convert them to PA State Plane in USSF.
You need to reproject the quad to State Plane. For a very small area a translate, scale, rotation will be close. But over a mile or two it is best to actually do the reprojection math.
Send me the upper left corner and the lower right corner coordinates and I will make you an image that is ready to go. Takes 45 seconds in AllTopo, I have base stock for the nation.
Feet or Survey Feet?
M
The Texas quads are in UTM meters but Penn is probably different. I could tell you how to do it in C3D but not sure how to query from one drawing to another in Carlson. You can do it manually by converting the lat/longs at the corner of the quad sheet to your NAD83 grid coordinates then create two points in your drawing at those coords insert the raster then scale and rotate the corners to those points. I'm sure someone here are Carlson can tell you how to insert it into your drawing a lot easier than that.
USGS Quad Map, Explain "Their Website"
i.e. where are you getting them from.
I was just looking at my USGS Quad Maps from the PA Map website. They are labeled USGS DCNR at the top and have NAD 83 PA South tick marks in meters which I like. I download tiffs. What I don't like is that the 8 adjoining Quad Map names are not on the sheet. I create a dwg for each quad.
For almost anything I do now, I only insert the orthophoto and contour shape file in my project drawing, quads still used for key maps. Only the trimmed key map area from my base quad dwg.
So why the Quad?
And yes, I do use the brute force scale and rescale method to insert quads.
I had used Mr. Sid files, but twice so far Windows updates have wiped out my Mr. Sid software package.
Paul in PA
USGS Quad Map, Explain "Their Website"
The client wants it. Its much easier exporting from Terrain Navigator on to a USGS layer (and better image) than inserting it as an x-ref from the USGS website. But... for now this is waht the client wants. We also have no problems with the LIDAR and Photos, just the quad map. I guess we will continue to manually adjust till we figure out how to insert.
Regarding The TFW File?
The TFW file for the orthophotos are in NAD 83 SPC feet. I create an image layer for each photo and a point-image/grid layer. I draw a point at the TFW reference E & N then draw four photo boder lines. I will then offset them to have an image trim border. First trim would be to 500' or 1,000' grid lines to reduce the image size to the project area and reduce the dwg regen time. If the image will be a part of the final drawing I will fine tune the image frame later.
The imported shape file puts the contours at the correct SPC coordinates. I use the reduced image frame to trim the contour file.
I do not understand the TFW file that comes with the quad sheet. I am trying to find the answer on the PA site and have downloaded one tutorial and have links to other tutorials. Quad sheet info was the first stuff I brought into CAD, so I am just used to doing it the old fashioned trial and error way.
Considering the precision of the quad data, close enough is close enough.
Paul in PA
