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Archive for June, 2009 Page 2 of 2



3DEM Website Is Gone, But 3DEM Still Available Here

I’ve covered the program 3DEM before on this blog; it’s a first-rate 3D terrain visualization program, and does the best out-of-the-box map relief shading of any free program I know. Here’s a standard USGS topo shaded with a digital elevation model using this program:

toporeliefshaded

Unfortunately, the author, Richard Horne, has ceased development of the program, and shut down the website permanently. But he’s graciously given me permission to host the last version of the program (version 20.7) here on Free Geography Tools; you can download it here. It comes with a full PDF manual, and my posts may offer additional insight on using it. I can offer some limited help if you run into problems, but any bugs in the software are there to stay.




LandSerf – Vector Functions

In a previous post, I gave a random overview of LandSerf’s strong terrain analysis functionality. But it  has some some useful vector functions as well, some derived from or related to raster elevation data, others more general. I won’t talk about the general vector data creation functions here; they’re perfectly fine, but lots of free GIS program can do that; instead, I’ll just highlight a few of the more distinctive vector functions that aren’t as common. Note: Save the derived vector data if you want to keep it; LandSerf doesn’t save created, modified or derived datasets automatically.

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LandSerf – Terrain Visualization And Analysis For Windows, Mac And Linux

I’ve been waiting for LandSerf 2.3 to officially come out of beta before posting on it, and that finally happened about a month ago. LandSerf is a Java-based GIS program with:

  • Terrain visualization and analysis functions (its primary focus)
  • Some vector functionality related to terrain analysis, plus other basic vector functions
  • GPS and Google Earth utilities

Today, I’ll walk through some of LandSerf’s basic terrain visualization and analysis functions; upcoming posts will deal with the vector and GPS/Google Earth capabilities.

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Early-Twentieth-Century Austro-Hungarian Military Maps Of Central And Eastern Europe

If anyone speaks Hungarian, perhaps they could translate the name of the site III. katonai felmeres for me. Fortunately, English text on the website explains what you find there: maps from the the 3rd Military Mapping Survey of the Austro-Hungarian empire, covering much of Eastern and Central Europe. The range covered goes from Istanbul in the southeast to Cologne in the northwest:

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Solid 3D Landscape Models From LandPrint

A bit of a departure from the usual posts, since this service is definitely not free. I just purchased a solid 3D landscape model from LandPrint.com and thought I’d review the creation process and the results, offer my opinion, and give some tips for getting the best results if you order your own.

LandPrint lets you select a square/rectangular section of the Earth’s terrain, and creates a small 3D model of that terrain along with your choice of overlays:

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PLSS Converters For The Western United States With DLLs, Code

1.  The TRS-data site at Montana State University lets you enter PLSS data (Township, Range, Section, “TRS”) for one of 17 western US states (AR , AZ, CA, CO, ID, KS, MT, ND, NE, NM, NV, OK, OR, SD, UT, WA and WY), and get back the latitude/longitude for the center of that section. You’ll need to know the correct meridian for the TRS section you’re interested in; the same site has a map that you can click on that will bring up a datasheet with the meridian. It also will give you information about the point you clicked on like latitude/longitude, slope, aspect, roughness, nearby landmarks,etc., but the scale of the map is so small that most of this data isn’t terribly useful.

2. The site above uses Martin Wefald’s free TRS converter software, available for free download. This includes a DOS executable, DLLs for use in other Windows programs (including both TRS to lat/long and lat/long to TRS), source code, documentation and a sample Visual Studio app for TRS to lat/long conversion that functions similarly to the above website:

trs2ll

3. Paul Jorgensen has used these DLLs to create more stand-alone converters:

- A single-point app for converting TRS to lat/long, or vice-versa:

trs

- A bulk converter that takes a text file with TRS data, and outputs a text file with lat/long data. Documentation and download at this website. The format the input data needs to be in is very specific, so it might not be the easiest to work with.

4. While I’m on the topic: I’ve posted before about the Township And Range website, which takes TRS data and plots the location in Google Earth. Since the original post date, the author has added converters that will take TRS data and convert it to lat/long, and vice-versa, with the option to view the location immediately in Google Earth.

HT to Steve Richardson.