World Wind FAQ

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World Wind FAQ v 1.3.0

Last Checked: March 6, 2005

Maintained by Llynix (Anthony Taylor)- llynix@gmail.com

Contributors:

Almost all the forum (and now wiki) posters (if you want specific credit please let me know)

Contents

Installation

Issues

Version 1.3
  • The installer requires about 700 megs on your windows drive (usually c:) to install. This is regardless of where you install it to.
Version 1.2e and older versions

Please install the Latest Version.

Downloading World Wind

The latest version is 1.3

This version is clearly marked if you go to Help->About in World Wind.

To get the latest version visit NASA_World_Wind_Download

Software Requirements

Microsoft Directx 9.0c

Microsoft .NET 1.1

Managed DirectX Libraries are installed with the program.

Recommended Specifications

  • Windows 2000, XP Home, or XP Professional (Win 95,98,ME is available with Full install)
  • 1.0 ghz CPU or higher
  • 256 MB of RAM (I run 128MB with no problems)
  • 3D Graphics Card (64 MB+ recommended, see Video Card Compatibility)
  • DSL / Cable connection or faster (I would hate to run anything else)
  • 2 GB or more of disk space

Bandwidth and Server Issues

Download Monitor

World Wind version 1.3 has a download monitor which can be very helpful diagnosing problems. Hold down Control (Ctrl) and hit H.

Problems connecting to OnEarth / Limited resolution compared to 1.2e

Recently the server at [onearth.jpl.nasa.gov] that was serving the original landsat layer blocked access to world wind users.

This is why older versions of world wind do not work without the proxy/mirror patch, and why newer versions of world wind (1.3) use the proxy patch by default.

Lucian at the onearth server has also asked us not to proxy the data. At this point the only access to the old landsat is the incomplete mirror served from worldwindcentral.com.

Work is underway to remedy this situation.

Can I use this for international locations?

Why is <insert geographic location.> fuzzy?

Why Can't I zoom in?

Just use the mouse wheel

Why am I not getting pictures like (this)

Why can't I see my house/car/etc?

Landsat 7 data is available globally and you can pick out many prominent features in your location. The resolution is 15m per pixel (Community/OnEarth Landsat) and 30m per pixel (NLT Landsat), so you can see major highways, airports, or city centers. However you probably won't be able to see your house and certainly not your car.

USGS data covers only the United States. You are more then welcome to view it all you want, but please don't complain that your area is not covered. The United States Geological Survey will unlikely collect data for areas outside of the US.

USGS 1m / topography cover most of the US. You can see most buildings and roads. You can probably find your house.

USGS Urban is about .25m/pixel and only covers certain areas in the US. These are the color images you may have seen. You can generally see cars with this layer. List of USGS Urban Cities

Work is in progress for additional data sets. While there is imagery for many other locations, most of this imagery is licensed and is not freely available. If you know of any public domain or unrestricted datasets that we can incorporate please feel free to tell us about it.

These forum posts have information about other countries: Norway Iceland Canada Australia

With the new landsat, what's with the colors? Why isn't my area covered?

NLT Landsat 7 button
NLT Landsat 7 button

Nasa Learning Technologies has stated there will be additional tweaking and alterations to the coloring. There will be a white paper describing the techniques used, and it will improve over time.

Consider this NLT global mosaic version 0.1, you haven't seen anything yet.

NLT servers are working around the clock to process the entire world. Currently only certain areas are in place. Please be patient your area will be there very soon.

NLT servers are also not as high quality as the original landsat is. This layer has not been pansharpened yet. NASA feels is it a higher priority to complete the full layer then it is to sharpen it as it takes 4x as long. As soon as coverage is complete look for a pansharpened layer to start trikling around the globe.

How do I load the .25 meter resolution maps, as shown in the screenshot of D.C. on this web site?

That is actually only accessible under the Layer Manager->Images->High Resolution Terrain Mapped->USGS Urban Area.

Enable that tree node and disable any other ones that are enabled in that particular list.

USGS Urban button
USGS Urban button
In 1.3 these images are also available by clicking the USGS Urban button.

All I see is white tiles when viewing the USGS Urban data!

USGS urban data is not available for all areas. The Urban Layer Highlighter is extremely helpful locating areas.

How large is the data set? Is it available for download?

Which dataset are you talking about?

The data sets collectively are well over 20 Terabytes. As such they are not available as a full package for localized download.

Work is in progress to release cache packs like those that were available for 1.2e. These will very likely be available via bittorrent, and if bandwidth allows via webserver.

How about bittorrent for the data sets?

Because of the size of the data used, and the limited amount of data users download of the total available data, it is unlikely that p2p would make much of a dent in the problem of serving that data.

But see above.

Why am I getting 'Problem connecting to server. Trying again in 2 minutes'

Several possible reasons:

  1. May be the server is down. You could say... try again in 2 minutes.
  2. You may be behind a blocking proxy/firewall. You'll need to configure a port remapper, or hunt down an admin to help.
  3. You could be in a country that blocks access to worldwind sites & download servers . Try to find a proxy.
  4. Remember to use the HTTP Download Monitor (CTRL+H) to see what exactly is going on

Why are the wrong image tiles showing up?

Possibly and probably due to the server bandwidth issues.

A work-around is to delete the numbered folders in the "cache" directory, but then of course you have to re-download all the images then next time you run the program. It's not obvious which particular cache files correspond to the "bad" areas.

You can also use a DDS viewer to browse and delete the offending files.

Nvidia's DDS viewer -- http://developer.nvidia.com/object/nv_texture_tools.html — By installing this you can switch to thumbnail view in the explorer and find and delete those nasty tiles.

Another good .dds format reader is Irfanview -- http://www.irfanview.com/

Also it is entirely possible that you are viewing more then one layer. Go to the layer manager and under images make sure only one box is checked. Otherwise things look very messed up.

If you do manage to find a "bad" tile using Nowak's server and upon reconnecting keep on downloading that same "bad" tile, please kindly send Nowak an email or message stating the filename and level (folder number) of the tile so he can delete it.

Tips

How do I know it's downloading data?

The NASA logo means that you are downloading imagery (attempting anyway). TerraServer (USGS) now has its own icon. You should also get a red box.

In 1.3 you can press CTRL+H and get and HTTP Monitor to see the tiles being downloaded in realtime, complete with URL's, filenames and return codes.

My video card isn't working?

Check out the Video_Card_Compatibility list. Please by all means edit it depending on whether yours works.

How can I extract data from Worldwind for use in other modeling and mapping applications?

All the data is cached in the installation folder under the "Cache" directory. It's organized by the dataset, however, images are in DDS compressed format. Please see above for DDS viewers.

You may have more luck reading up about the WMS protocol, and then interfacing with the same servers that WW connects to.

Are images on World Wind copyrighted?

The Landsat Global Mosiac, Blue Marble, and the USGS raster maps and images are all Public Domain.

Can I use images on World Wind for commercial purposes?

The various servers you receive data from do request that you give them credit, however this is not required. You may do what you wish with these images.

Windows 95,98,ME compatibility?

New versions shouldn't have a problem running unless it is due to an older computer / video card. I would appreciate some feedback on this. The latest version removed the texture converter code so the annoying black dos box shouldn't show up.

Can I copy my cache data to another computer?

Yes you can. Click here for discussion.

What is the most proportionate "vertical exaggeration"?

Although it seems that 2 or 3 should be the "correct" vertical exaggeration, "1" is the correct and real vertical exaggeration. More correctly, "1" means that the vertical height is multiplied by 1.0, whereas vertical exaggeration of 3 means that vertical height is multiplied by 3.0.

Why am I getting an error about "mscorwks.dll"?

Most likely, you've got .NET 1.0, but World Wind requires .NET 1.1. Just download it from here, and you should be up and running.

Secret Keys

  • Wireframe: Cntrl+W
  • Diagnostic Info: Cntrl+D

Why does <insert mountain or other relief feature> not look like it should?

Illustration
Illustration


This is due to the fact that the elevation data, SRTM, is taken much like sonar measurements - the elevation is "sounded" from a satellite. Unfortunately, these "soundings" are only taken about every 90 meters, so the data isn't incredibly accurate. As a result, mountains and such (for example, Matterhorn) may look strange. Imagine the satellite collects elevation points in a grid. So it flies over the Alps where two peaks are 50 meters apart. It takes one reading, say, 40 meters away from one peak's top, but manages to hit the highest point of a different peak right on the top. It never hits the first peak's tippy top.


Referring to the illustration, say the vertical blue lines are measurements taken. The red line will be what Worldwind shows, grey being the actual landscape. The left peak shows as being higher in WW, but the right one is actually the highest.

How to make use of the USGS layers

USGS is the acronym for U.S. Geological Survey. In other words, the data that is available in the USGS layers is only for the USA. While it is possible that similar data is available for other parts of the world, most of it is not freely available, and therefore is not incorporated into World Wind.

Step-by-Step instructions with examples

The Degree Confluence 48°N 122°W is located to the east of Seattle, Washington state, USA.

Using this link should open World Wind, and have it centered on 48°N 122°W, at an elevation of 10,000 meters. If the link doesn't work for you, open World Wind, enable Lat/Long lines, and use them to guide you in getting to 48°N 122°W, and then zoom in to about 10,000 meters elevation.

You should enable Lat/Long lines(F7) and/or Cross Hairs(F9), and the Position display(F10).

Select the USGS Digital Ortho layer as the layer you want to display. Also known as the USGS 1m Ortho layer.

Unless you already have the data in the cache on your hard disk, World Wind should now download the layer data from the servers. That includes both the aerial photograph images from Terraserver and the terrain height data (i.e. elevation data) from NASA.

You should now wait for World Wind to complete the data downloads. The amount of time will vary depending on the speed of your Internet connection and the load on the servers. While writing this, it took seven minutes to download all the data for this first example, using a PC on a high-speed connection.

An example of what you will see during the USGS Digital Ortho data download for 48N 122W
An example of what you will see during the USGS Digital Ortho data download for 48N 122W
The "Terrain Elevation" is showing a value because terrain height data has been downloaded. The "USGS logo" in the lower right corner indicates World Wind is currently downloading USGS data. The red lines indicates that the current image tile that is being downloaded covers the lower right portion of the displayed area. The upper right portion of the displayed area has a clearer image, because World Wind has already downloaded the best aerial photo data for that area for use in displaying the view from the current elevation of 10,000 meters.
An example of the display after the USGS Digital Ortho data download for 48N 122W is complete
An example of the display after the USGS Digital Ortho data download for 48N 122W is complete
Once the USGS Digital Ortho data has finished downloading you should see a display similar to this example. In this example, Lat/Long lines, Cross Hairs, and Position are enabled.

Now select the USGS Topo Maps layer as the layer you want to display.

An example of the 'fuzzy background' before the current layer's data is downloaded
An example of the 'fuzzy background' before the current layer's data is downloaded
The display will start as just a 'fuzzy background', which is actually the World Wind Blue Marble layer zoomed in 'too far'. The data download may take some time, but this time World Wind doesn't have to download any terrain height data, because it will use the same data downloaded when the USGS Digital Ortho layer was being downloaded.
An example of the display after the USGS Topo Maps data download for 48N 122W is complete
An example of the display after the USGS Topo Maps data download for 48N 122W is complete
Once the USGS Topo Maps data has finished downloading you should see a display similar to this example. In this example, Lat/Long lines, Cross Hairs, and Position are enabled.

Now select the USGS Urban Area Ortho layer as the layer you want to display. The display will start with the fuzzy Blue Marble display, and may take a while, but the terrain height data doesn't need to be downloaded.

An example of the display after the Urban Area Ortho data download for 48N 122W is complete
An example of the display after the Urban Area Ortho data download for 48N 122W is complete
Once the Urban Area Ortho data has finished downloading you should see a display similar to this example. In this example, Lat/Long lines, Cross Hairs, and Position are enabled. Parts of the display are "blank" because the USGS Urban Areas data only covers specific parts of the USA. World Wind gets the USGS Urban Areas data from Terraserver. Terraserver gets the data from the USGS. The USGS website has information about their High Resolution Orthoimagery. They also have a list that shows what areas are covered. Terraserver has to get the data from the USGS, and process it before it becomes available on Terraserver, so there may be differences in what is available in World Wind, both in regards to the areas covered by the Urban Areas data, and as far as the resolution of the available data.

As a comparison with the USGS layers, select the NLT Landsat7 (Visible Color) layer as the layer you want to display.

An example of the display after the NLT Landsat7 (Visible Color) data download for 48N 122W is complete
An example of the display after the NLT Landsat7 (Visible Color) data download for 48N 122W is complete
This layer is an image created from digital data collected by the Landsat7 satellite. The USGS Digital Ortho and Urban Area Ortho layers are images created from aerial photographs.

Each layer has different characteristics, including the "usable" resolution for the layer. The NLT Landsat7 (Visible Color) data has a resolution of 30 meters per pixel, so each pixel in the image represents 30 meters on the ground. The USGS Digital Ortho data has a resolution of 1 meter per pixel. The Urban Area Ortho data resolution is less than one metere per pixel. Another difference between layers may be the date when the data was collected, so you may see features that are different when comparing layers.

Select the USGS Digital Ortho layer as the layer you want to display.

An example of the display after zooming in on the USGS Digital Ortho data to an Altitude of 550m above 48N 122W
An example of the display after zooming in on the USGS Digital Ortho data to an Altitude of 550m above 48N 122W
Now zoom in from the current Altitude of 10,000 meters to as close as you can get to the earth, which is an Altitude of 550 meters. When zoomed in to this level, the display is blurred because you have zoomed past the "useable" resolution of this layer's data.
An example of the display showing the USGS Digital Ortho data at an Altitude of 1100m above 48N 122W
An example of the display showing the USGS Digital Ortho data at an Altitude of 1100m above 48N 122W
Now zoom out so the Altitude is about 1100 meters above 48°N 122°W. The 'cross' in the middle of the display is part of the images retrieved by World Wind from Terraserver, and represents the location 48°N 122°W. You can confirm this by enabling Lat/Long lines(F7), or Cross Hairs(F9) and Position(F10).

At this point the display in World Wind is equivalent to "looking straight down" from 1100 meters above 48°N 122°W. Of course you can do things in World Wind such as rotating the view to see the terrain features, but the "view from above" is essentially the same as can be displayed directly using the Terraserver website. From the webpage for the 48°N 122°W Degree Confluence if you select the "aerial" maps link, you will go to a Terraserver page that shows essentially the same view as the above World Wind example. This Terraserver page shows that the data was collected July 25, 1998 (7/25/1998). The info link shows that the resolution of the image is 1 meter per pixel.

Future Versions

When will the next version be out?

Just wait for it. World Wind is under active development. We haven't forgotten about you.

Is there a way to set a proxy?

The current version of worldwind has limited proxy support. (I believe it defaults to the proxy settings in Internet Explorer.) Future versions should feature a more robust proxy support.

Do you think you could add boundaries of other sub-national entities, such as Swiss cantons, Australian states, and Canadian provinces and territories?

Chris : It's coming.

Llynix - the only reason these files aren't in there is they haven't been generated yet. If you have some free time, and a basic knowledge of computer programing why not volunteer to convert them?

Please see Additional Boundaries

Any chance a future version could make the amount of cache adjustable?

This is done, please see your WorldWind.exe.config file.

Is there a way to narrow down a search for a place?

We realized this problem almost immediately (there are approximately 2 million places with 3 million more about to be imported) and we're going to associate a "Place" with a country or geographic identity. Perhaps you will type in "Paris France" and you will only get matches that have those two keywords. Also, if anyone hasn't noticed, the searching tool is case sensitive, and that will of course be changed as well.

In addition, we want to display more meta-data information about a particular place, such as the type of place(mountain, populated place, beach...), and perhaps attributes such as population or elevation. We of course are open to suggestions that anyone else might have in terms of what would be useful.

Several people are working on placenames right now. Stay tuned.

There are place names all over the place!

Yes, the amount of placenames is a bit of a nuisance, and we're working on ways to remedy this problem. We still want those placenames in there, we just don't want them to take up so much real estate on the screen.

— Side note,if you go to the layer manager (tools / layer manager) under placenames you can click off certain ones. It may be helpful to remove the one labeled "US Anthropogenic Features" which contains info about churches, schools and other landmarks in the US.

The entire time the application is running, it uses 50-100% of the CPU, why?

World Wind was not coded for performance, sadly. At least, you can rest assured that this problem is very common and most users experience it - there is nothing wrong with your computers. This will get optimized in future releases, but we're still heavily in the Research & Development stage.

Also there are a few bugs attributed to high CPU usage. Check out:

http://learn.arc.nasa.gov/worldwind/forums...p?showtopic=372

How about other planets?

Mars is in beta testing right now. I am personally hoping for Venus next, but with the data available it may likely be the moon..

I would love to see a feature that showed day/night in realtime say taken from the USNO atomic clock. Perhaps a setting where you could follow the terminator and such.

It's on our list, slightly more elevated now that you asked for it.

Stars?

Chris : We actually have plans to import a "Military-Grade" star map. It's probably overkill, but we like it that way.

I think Chris is referring to: http://skyserver.sdss.org/dr1/en/

Maybe we could use same star catalog as Celestia: http://www.shatters.net/celestia/download.html

Developers

What license are you releasing under?

Nasa Open Source license v1.3.

Will World Wind remain always free?

Chris:

The program itself is open-source and will always be free. Access to NASA provided data will also remain free. However, there might be private companies that want to provide their data through World Wind (perhaps magazines or encyclopedias) and perhaps might charge a fee for access to their data. As long as there are people who want NASA provided data, and are using World Wind for that purpose, it gives the departments in charge of providing data a reason to ask for more funding to improve bandwidth to the data.

Why did you decide on C# and DirectX?

See this forum posting: http://learn.arc.nasa.gov/worldwind/forums...w=findpost&p=17

Mac and linux ports?

Since this is open-source, we encourage any OSX programmers to start a port and we will try our best to provide whatever resources we can towards the effort. Right now our development staff consists of one programmer and one graphics designer, but we are an ambitious duo so we will do our very best to please everyone.

For more information:

http://learn.arc.nasa.gov/worldwind/forums...p?showtopic=133

In what areas do you need the most help? How can I contribute?

World Wind's sourceforge page lists the latest bugs and feature requests. The developers use these pages as the current "TODO" list.

Several people have mirrored cache file content and the worldwind main program. If you have available bandwidth please consider adding a mirror.

Feel free to write up documentation on the wiki or reporginize, every question you answer is a question that an admin doesn't have to. This leaves them more time to hopefully give us a better worldwind.

Some international users have begun to look into the possibility of incorporating local data sets into worldwind. If you are an international user it would be helpful to locate where datasets are stored, and any licensing / copyright problems. I'm sure this will give our developers a leg up and speed up the process of integrating international data.

People who speak another language then English can help with Translating the installer.

Feel free to contribute to this faq.

<shameless plug> Why not check out the other things World Wind Central has to offer. </shameless plug>

When is the planned migration to sourceforge?

Done! CVS is up and people are adding bugs and feature requests.

https://sourceforge.net/projects/nasa-exp/

Links

What data does World Wind use and where can I access it?

Here is a partial list that I came up with.

Where can I find more links?

Please see this forum : http://learn.arc.nasa.gov/worldwind/forums...owtopic=411&hl=

And this forum : http://learn.arc.nasa.gov/worldwind/forums...owtopic=679&hl=

Simplified Chinese Version of this FAQ

SC Unofficial FAQ

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