#Topographical maps?
10 messages in this thread
you might try USGS DEMs (Digital Elevation Models). There are many programs
that can convert these to a mesh file, though they can get very large. Topo
maps usually only have simple contour lines that would have to be digitized
manually- A time consuming process. The company I work for has all the stuff to
do this sort of thing. Let me know if you want more details.
The DEMs I have available to me are each over 10 Megs, so that won't
work, but, I have just located some ascii files; longitude, latitude and
elevations at 1000' intervals. How might these be converted? Thanks for the
reply.
ian
I would have to look at one to tell you for sure, but I have a program that
could probably read them in. You have 10meg DEMs ? the biggest I have seen are
only a little over 8. Size isn't necessarily important, just how much detail
you want. Normally the files do get fairly large, though.
I missed the beginning of the thread too, but have spent alot of time
with DTMs and 3DS. Are you wanting to get topo in? I would say
don't but a DEM. You will spend as much time fixing it as you would
digitizing it. We just digitized 150 square miles in four days and
the grid itself came out exactly as we wanted it. Has we purchased
the DEMs, we would have probably spent at least that much time fixing
stuff. In particular, features such as steams NEVER line up.
We then use Schriber's QuickSurf to manipulate the topo data into our
grid. That program has many other very nice features for 3D
topographic rendering.
If this is the kind of stuff you guys were discussing, let me know. I
can probably provide some other suggestions. If I'm way
off,….never mind <g>.
Sent my message to you to J.K. Jordan by mistake. Basically just a
rehash of my 9.3M DEM files. Thanks for the help, I think the density
of those files is major overkill for my modest flyby intent. Thanks
again.
DEM's are available in more modest dimensions than 10 megs, by the
way. I have a few that are only a few megs or smaller in size.
Depends what range of are you want, or you can thin out really
complicated ones as well. I have spent some time experimenting with
these at work, and have had a few decent ones. Since these don't
specificly fall within my prescribed duties, I havent had a lot of
time to perfect them.
>>ascii files with long, lat, elev…
I missed the beginning of this thread, but are you looking to put
terrain into 3DS? I bought a program from Schriber called 3DSURF
($150 I think) which will read an ASCII file directly and create a 3D
surface.
If your data happens to be or can be converted to a rectangular grid
of elevation values, you can use a program I wrote and uploaded to
the forum (MATHDX.ZIP, free) which will create a DXF surface which
can be loaded into 3DS. I your data is not on a rectangular matrix,
you could write a program to interpolate to create a the matrix.
Also, a package like Jandel's 3D TableCurve or Mathematica could fit
a surface to the irregular data and create a matrix for MATHDX. Of
course 3DSURF would be a lot easier.
If you just have one to convert or want to try a sample, I'd be glad
to run it thru 3DSURF for you.
Sorry about the message mixup……..am interested in 3DSURF. Let me know
the best way to get it to you. I have nine files covering the Hawaiian Islands
,each about 10 to 20 K. Very simple list
-156.6585735 21.0127966
-156.6576463 21.0119466 etc. I
have your program Mathdxf, I'll check it out as soon as I logoff. Thanks again,
I'll drop you one of those files if you've got the time and we can negotiate on
the rest if that's kosher.
ian
>>20K files…
Great, ian – just zip them and send a few by CIS binary email. I
assume the data format you illustrated also includes elevations? I'll
try to process and send you back a 3DS file.