USGS DATA MAP HELP

[Dakota]

Hi Guys,

I would like to make some Terrain Mesh for California for FSX and am having problems finding the right elevation maps on the USGS website. I have never done this before because it seemed quite complicated. I have watched the great tutorial video from "MBOY3515"

However the link to "seamless.usgs.gov" he refers to does not work anymore since the USGS has updated its website.

Can someone tell me if there is a tutorial around on how to download the necessary file from the new USGS web site to import and convert in the Global Mapper. The new layout of the USGS website is probably better but I have no clue how to get the needed file.

Thanx in advance!

 

[JRobinson]

I use the "download by bounding box" option usually, you just draw a rectangle around the basic area of interest (zoom in, make it no larger than you need otherwise the list of available tiles will be so huge you'll never figure out which ones you want). It should pop up a menu where you select ie. Orthoimagery, DEM products, etc. Select the DEM products and then you should get a list of tiles needed to cover the area you selected. You can click on these items and it'll show you the extents of the product on the map. Select the ones you want by placing a checkmark in the column on the left, when finished click "Add Items to cart", that will take you to your cart where you can once again review by clicking on each item and seeing the coverage area. Click "Checkout" and you'll be asked for your email address (twice), click "Place order" and you'll get an email with links to the products you selected.

If you do this a lot or have large orders with many tiles it becomes difficult to manage the links in the email so have a look at the TNM bulk downloader tool (link in your email). Download the stand-alone download manager (TNMDownloadManager__V1.1.jar) and put it in a folder somewhere otherwise you have to download it every time you use it. Double click TNMDownloadManager__V1.1.jar (you need Java installed and up to date) and paste the order number from your email into the box then click "Add Order", your items should appear in the list below. Select a Save directory under File > Options and also check "Enable use of server filenames", then click "Start all", they should download one by one. I find I can download the tiles at a much better speed using the download manager than if I just click the links in the email so I use it even when I just want one tile.

Jim

 

[Dakota]

Thanx Jim,

could you post the URL you are using. The USGS website is quite complex and I do not know what you are referring to.

 

[JRobinson]

This is the link I have saved in my favorites:

http://viewer.nationalmap.gov/viewer/

You'll see a row of icons just above the map, "Download by bounding box" is the 2nd from the right.

 

[Dakota]

Thanx Jim for your reply,

I get the following page when going to: SEE ATTACHMENT
http://viewer.nationalmap.gov/viewer/

There are no icons above the map. Further help much appreciated!

 

[JRobinson]

It takes a while to load, maybe 10-15 seconds, those "new launch page" things should go away and then you'll see the map, did you give it sufficient time? Not running any script blockers? I don't recognize your browser, I know Firefox works, or else try Internet Explorer.

EDIT: I just tried it with IE which I don't normally use, I see now if you've never been to the site before it may actually take more like 30 seconds to load.

 

[Dakota]

I was using Chrome that's why it didn't work. It was probably running a script blocker. I switched to Explorer and everything worked as you explained.

Thanx again Jim!

 

[JRobinson]

You're welcome, glad you got it sorted!

 

[Dakota]

Hi Jim,

I think I need to bother you once again. Finding and downloading Data works fine now but the problem is that the tutorial I have, refers to the old USGS web site and file types that can no longer be downloaded. If you have a minute could you maybe explain in a few steps how you make mesh terrain for fsx of the US using the Terrain SDK.

Much appreciated!

 

[JRobinson]

I assume you got an IMG from the server rather than a geotif and that's the stumbling block? You need to install OSGeo4 and convert your IMG to a geotif by running a command like this in the "OSGeo4W Shell":

gdalwarp -of GTiff -co "INTERLEAVE=PIXEL" -t_srs "+proj=latlong +datum=WGS84" -r cubic "Path\to\input.img" "Path\to\output_WGS84.tif"

That should get you the geotif you most likely need to complete the tutorial, otherwise you could use "DeathValley_Elevations.inf" in the SDK\Environment Kit\Terrain SDK\Resample Examples folder as a template and substitute your own filenames for the .tif and the output .bgl. Then you just drag/drop the .inf on resample.exe and that's about all there is to it. Post back with more specifics if you get stuck.

Jim

 

[Dakota]

Hi Jim,

thanx again for your reply. The basic problem I am having, since I have never done this before, is downloading the propper File to make a mesh terrain with the FSX SDK. If I follow the steps as you previously explained I have the option of downloading different File Types such as: ArcGrid, BIL, Geo TIFF, GridFloat, IMG, Shapefile or TIFF.
Which one do I need?

IMG would mean I need to previously convert it as explained. If I download a GeoTIF then I wouldn't need to go through the conversion process with OSGeo4. Is that correct? What about ArcGrid or BIL?

I also have to choose the resolution and Product. 1/3 arc seconds or 100 meters, Grayscale or Color Relief? Any Tips?

I also noticed that when I did a test Download I got a map of the entire US (1,4 GB). I thought I would only get a map of the region I selected.



Help is much appreciated!

 

[JRobinson]

...If I download a GeoTIF then I wouldn't need to go through the conversion process with OSGeo4. Is that correct?

From the list of options I'd say go for either the IMG or Geotif but whichever you download will probably need to be reprojected to WGS84 even if you're doing geotif to geotif so you'll most likely need OSGeo4 and the gdalwarp command regardless. If not now, you'll need it eventually as long as you play around with resampled things anyway. I'm not much of a mesh person, I've made about 3 small meshes is all, but my understanding is the lower the number of arc seconds (terminology? lol) the higher the resolution. The ones I downloaded for my project were 1/9 arc second which does work out to be an improvement over default mesh for the US, the result was LOD14 where default for the area in question was LOD10. My understanding is that 1 arc second sources yield LOD10 mesh so that must be what MS used for the default (in the US, less for the rest of the world).

If you got a map of the entire US it must have been because you selected a very low resolution and the size of the tile on the server simply covered the entire US. The sources I downloaded were very small covering only an area the size of a small city and they were anywhere between a meg and ~130 megs apiece, they overlapped strangely (from a photoreal person's perspective) so to get the coverage I wanted I needed to multi-source 5 chunks together in the .inf and arrange the [sources] in such a way that one wouldn't cancel the other out. In retrospect I probably should have used -te West° South° East° North° in my gdalwarp commands to trim the sources so there was no overlap but I got the job done and the mesh came out great after fussing around a bit.

I would select your area again and for example if 1/9 arc second data is available tick all the boxes that say 1/9, if only 1/3 arc second data is available then tick all the boxes that say 1/3, etc. I think these will most likely be in IMG format. If you want to disclose your location I could have a look myself and maybe give you a better idea how to proceed.

Jim

 

[Dakota]

Thanx a lot for the advice. I'll give it a try on the weekend and report back, but now that you've explained everything in so much detail I hope to get it to work.

 

[Dakota]

Hi Jim,

okay, slowly but surly I am getting a grip on this thing. Downloading worked fine. I downloaded the IMG file of the desired area and installed OSGeo4W.

Since I am not a programmer please be patient with me and explain the command line a bit more in detail.

Your example command line: gdalwarp -of GTiff -co "INTERLEAVE=PIXEL" -t_srs "+proj=latlong +datum=WGS84" -r cubic "Path\to\input.img" "Path\to\output_WGS84.tif"

So if I understood things correctly then I need to type the command line into the black screen.

Entering the path to the image and place to save new file is clear, but where can I find the latlong information to put into the command line?

gdalwarp -of GTiff -co "INTERLEAVE=PIXEL" -t_srs "+proj=latlong +datum=WGS84" -r cubic "Path\to\input.img" "Path\to\output_WGS84.tif"


Thanx again!

 

[JRobinson]

It's best if you compose your commands in Notepad then you just copy them, right click the OSGeo4W Shell window, and select "paste" followed by the "Enter" key which will save you a lot of typing errors. The lat/lon is already embedded in the .img file so you don't have to worry about that unless you want to trim down the source for some reason but don't worry about that right now.

Once you end up with a WGS84 geotif you can run the gdalinfo command (also from the OSGeo4W Shell) on the finished product to get your coordinates if you need them for some reason:

gdalinfo "Path\to\output_WGS84.tif" > "Path\to\output_WGS84.txt"

...which will output a .txt file containing the cords of each corner.

You really don't even need to know that though as long as your georiff has the info embedded, resample can get what it needs straight from the geotiff. I would try this .inf, replacing your actual filenames under "SourceFile" and "DestBaseFileName"

[Source]
Type  = GeoTIFF
Layer  = Elevation
SourceDir  = "."
SourceFile  = "output_WGS84.tif"

[Destination]
DestDir  = "."
DestBaseFileName  = "output_bgl_filename"
DestFileType  = BGL
LOD  = Auto

Save the .inf in the same directory as the output.tif (somewhere outside of Program Files (x86)) then just open the Microsoft Flight Simulator X SDK\SDK\Environment Kit\Terrain SDK folder in another window and drag/drop the .inf from one window to the other dropping it on resample.exe. It should start compiling and in a couple minutes you should end up with a mesh .bgl in the same folder as your output.tif and your .inf. You can then drag the .bgl into TMFViewer to see if everything worked out OK.

Good luck, post back if you run into problems .

Jim

 

[Dakota]

Thanx Jim!

everything worked out perfect! I really appreciate your help.

 

[JRobinson]

You're welcome, congratulations!

 

[annber]

Hi Jim, I just read this thread because it is exactly my problem, except I am lost. I am doing the Island of Culebra, of Puerto Rico. I downloaded per your instructions above a file which contained a bunch of stuff, including the IMG file. I am totally lost at the command line, gdalwarp -of GTiff -co "INTERLEAVE=PIXEL" -t_srs "+proj=latlong +datum=WGS84" -r cubic "Path\to\input.img" "Path\to\output_WGS84.tif". My understanding is that I need to change the"path\to\input.img to the the text reflecting where my IMG image is, right?
-for example, I have it downloaded to New folder(10) on my desktop, so the path would be C:\Users\bernardo\desktop\New folder(10), is that right?
-and what would the ouput path be?
excuse my utter ignorance once more.

 

[JRobinson]

Hi Bernardo, yes that's basically it, you could do something like this:

gdalwarp -of GTiff -co "INTERLEAVE=PIXEL" -t_srs "+proj=latlong +datum=WGS84" -r cubic "C:\Users\bernardo\desktop\New folder(10)\ned19_n44x75_w069x00_me_northcoast_2010.img" "C:\Users\bernardo\desktop\New folder(10)\ned19_n44x75_w069x00_me_northcoast_2010.tif"

...where "ned19_n44x75_w069x00_me_northcoast_2010" was one of my own filenames, use whatever your .img is named. Output can be whatever and wherever you want it to be, "C:\Users\bernardo\Documents\Culebra.tif" would also work fine if you wanted to output to your documents folder for example.


Another thing you can do after starting the OSGeo4W Shell is paste cd "C:\Users\bernardo\desktop\New folder(10)" and hit enter. ("cd" is "change directory", use cd /d if you're changing from one drive to another) Then you won't even need the path, you can just use a command like this:

gdalwarp -of GTiff -co "INTERLEAVE=PIXEL" -t_srs "+proj=latlong +datum=WGS84" -r cubic "ned19_n44x75_w069x00_me_northcoast_2010.img" "ned19_n44x75_w069x00_me_northcoast_2010.tif"

Jim

 

[annber]

Hi Jim, thanks for quickly replying. Following your instrauction I was able to convert the IMG file to a TIF file. I then followed the tutorial where I created an .inf file and dragged it to the resample.exe in the Terrain SDK.
Problem is it did not compile, and I was able to screen capture the attached image. When you have time, could you help? Thanks.