Using T2 to create a "fly-thru" of a real valley

[Oshyan]

Very good ideas. I look forward to seeing the results!

- Oshyan

[pw_evc]

Tool like this have great potential for use amongst urban planners, environmental planners, etc.  Can T2 visualize scenarios of water drainage/flow?  What I'm thinking is that it'd be awesome to be able to show a real hillside and the impacts/results (animation) of water flow patterns with various scenarios of land cover, ie. trees v. grass v. parking lot v. building.  I doubt T2 has this capability, but I thought I'd ask. 

Likewise for river flow and sea level changes.  Could I place a virtual dam on a realworld river and view the results?

Okay, enough from me.  Off to bed and I'll look forward to reading your response in the morning.

-Peter

[Oshyan]

TG2 can't actually simulate water drainage beyond an extremely simplistic and mostly random "river generator". However you could import river simultaneous in either image/image sequence (used as a mask) or geometry (particle simulation for example) using the new geometry sequence support (see 2.3 release announcement). So the actual simulation data would be generated in another app and then exported in a TG-compatible format.

You can however do flat bodies of water natively in TG, change their altitude/size, etc. So you could simulate damming a river to an extent, or water level changes throughout the season.

- Oshyan

[pw_evc]

Ryan, I attempted your new tutorial, but didn't get very far due to a stall in the downloading data process. After clicking all of the download links beside each file, I got a bunch of small windows that said "Current order status. Adding your request to the queue... Please wait for the data to be returned."  Eventually they turned to "Current order status. Extracting data... Please wait for the data to be returned." All of this was expected to this point and I figured that another pop up would come up telling me the download is done and give me the option to open or save a zip file, but that never happened. 

Is this normal?  Does it just take a really long time (hours)?  Can you suspect any common mistakes I may have made? 

thanks,
Peter

[RArcher]

No that is not normal.  I would start with downloading one file at a time, not requesting them all be created at once.

The window should read:

1. Adding your request to the queue
then
2. Extracting Data...
then
3. Creating the archive file
then
4. Data extraction complete

At this point you will get a standard download box asking you where you want to save the file.  Unless of course you have your browser set to autodownload things and put them in a standard spot...

There will also be a link in the last window that says Data Extraction Complete that you can directly click on if the regular download box doesn't pop up.

All of this takes a couple minutes depending on how busy the server is and how large the data file you requested is, but it most certainly should not take hours.  Perhaps they were having server issues.

[pw_evc]

I finally got the USGS downloads to work.  My error lied in the fact that I overlooked this sentence you wrote in the last message, "There will also be a link in the last window that says Data Extraction Complete that you can directly click on if the regular download box doesn't pop up."  The exact line that comes up for me is, "If an error occurs during download, click here to retrieve the download bundle. After one hour, the download bundle will be automatically deleted from our server."  The word "here" is hyperlinked.  I click on that, and all familiarity returns. Perhaps you should include this little troubleshooting step in your tutoria.

Also, Terragen 2 completely crashes when I try load a JPG2000 file.  I assume this means it cannot read jp2 files, but wanted to confirm in case it does and I'm doing something wrong.  jp2 files are much smaller then regular jpg's, that's why I tried to use it.  I was successful at loading a jpg of my AOI into T2, but I had to dramatically reduce its size (PhotoShop) for it to work.  Time will tell if the resolution will be adequate.

[Oshyan]

TG2 does not currently support JPEG2000 files. Additionally, the size of the file will ultimately have no direct affect on the amount of memory it uses when loaded. Memory use is directly determined by the size of the image and its color depth and number of color channels as compressed images are decompressed before being usable in Terragen (and most any other application).

So for example:

A 1000x1000 image has 1,000,000 pixels.
For a color image, you have 3 channels, red, green, blue
Each channel normally contains 8 bits of data to represent the color value
There are 8 bits per byte
Thus each channel is 1 byte
3 channels = 3 bytes per pixel
Times 1,000,000 and you get 3,000,000 bytes or 3 megabytes.

So all that really matters is image resolution and color bit depth. In the case of GeoTIFFs they are very often 32 or 16 bits per pixel, but also often with a single channel (grayscale).

- Oshyan

[pw_evc]

Okay, so I successfully completed Ryan Archer's USGS Elevation Data with Terragen 2 tutorial.  Now I'm trying to apply what I learned to my own data and it is not working.  The reason being that my image layer is much larger in memory size that T2 won't accept it.  I can't figure out to get the file size down.  I'm able to get it small enough as three separate images, but then I can't figure out how to get them to align properly in T2.