KenMankoff

YAGEL – Multiple Balloons on Mars

I’m releasing Yet Another Google Earth Layer, this one featuring some more KML tricks and hacks pushing Google Earth to do things that Google does not officially support: multiple placemark description balloons visible at once.

Download: Mariner Mars 1971 (MM71) Ultraviolet Spectrometer (UVS) Data in Google Earth. This is a work in progress as part of a Planetary Data Restoration Project at the Laboratory for Atmospheric and Space Physics and as such the data is not finalized and is subject to change.

The data comes from the Ultraviolet Spectrometer on the Mariner Mars 1971 spacecraft, and had previously been processed for the Albatross software tool back in 2002. Neither Google Earth nor its predecessor KeyHole, nor even KML, existed back in 2002, and the data needs to be accessible in a more modern and accessible visualization tool (Google Earth) in order to remain useful.

The footprints are where the instrument was looking. In each of these regions a spectral range from 2107 to 3497 Ångströms was sampled, and the spectra are visible in both the hacked multi-balloon display, and in the more detailed official Google Earth balloon visible by clicking on the footprint. Each footprint is colored, both in the map view and in the sidebar, by the response at 3049 Å, which is roughly where the ozone signal is. For more information on the data and science see the references listed at the end of this post.

Previously I implemented vertical data “curtains” in KML, useful for oceanographic transects, seismic lines, spacecraft looking down through the atmosphere in profile (as opposed to a 2D surface image), or any other vertical data. Along with vertical data (solved) and subsurface data (no known work-around), another major limitation of Google Earth is that only one description balloon is allowed to be visible at a time. However, Google Earth does support multiple placemarks (by default yellow pushpins in Google Earth, or red pins in Google Maps). The hack to get multiple balloons visible at once is to make custom icons that look like balloons and then use them in place of the default icons. If this technique is used it is advised to implement various other KML features to make the balloons only appear in certain views and therefore avoid overwhelming the viewer. I’ve used both the TimeStamp and the Level of Detail features to limit when the icons appear.

@article{barth1974atmosphere,
  title={{The atmosphere of Mars}},
  author={Barth, C.A.},
  journal={Annual Review of Earth and Planetary Sciences},
  volume={2},
  number={1},
  pages={333--367},
  year={1974},
  publisher={Annual Reviews}
}

@article{barth1971mariner,
  title={{Mariner 6 and 7 ultraviolet spectrometer
                   experiment: Upper atmosphere data}},
  author={Barth, CA and Hord, CW and Pearce, JB and
                 Kelly, KK and Anderson, GP and Stewart, AI},
  journal={J. geophys. Res},
  volume={76},
  year={1971}
}

Mars Geology

Data from the U.S.G.S. PIGWAD site converted to display in Google Mars. View the KML layer or the legend (also available through the layer).

Mars Geology

@conference{skinner2006digital,
  title={{Digital renovation of the atlas of Mars 
         1: 15,000,000-scale global geologic series maps}},
  author={Skinner Jr, JA and Hare, TM and Tanaka, KL},
  booktitle={37th Annual Lunar and Planetary Science Conference},
  volume={37},
  pages={2331},
  year={2006}
}

Vertical Data in Google Earth

Google Earth does not officially support vertical curtains of data. However, it does support buildings with images on the side. If you are willing to stretch the definition of a building, you can put any vertical data you like into KML. This implementation was inspired by the Goddard Earth Science (GES) Data and Information Service Center (DISC) sample files for CloudSat, CALIPSO, and Aqua.

If you use IDL and would like to image your data in Google Earth, be it points, lines, regions, surface images, or vertical data, you should be using my IDL interface to the KML API.

Vertical Data in Google Earth

Earthquakes

I came across a database of earthquakes from 1960 to almost present. I converted it from the existing form to KML so it can be seen in both Google Earth and Google Maps. Both views incorporate a temporal component.

For the Google Earth view, magnitude as been encoded as pin size and depth has been encoded as height above the Earth. A few interesting regions where the deep quakes occur, such as east of the Andes, pop out.

Earthquakes

Pine Island Glacier Publication TimeMap

In which I present a rough geo-spatial-temporal map of Pine Island Glacier (PIG) publications.

Geo-spatial-temporal time-map of Pine Island Glacier (PIG) publications

More »

GISTEMP.StationData

NASA GISS has recently announced another year of the surface temperature trends. Last year, 2009, tied for the 2nd warmest year on record, and the past decade (January 2000 to December 2009) was the warmest on record.

I took the time this weekend to re-create a Google Earth layer showing these data. This visualization allows you to see a broad geospatial overview, and then select any particular location and see both long-term trends and even the data point for each individual month.

Download (330K)

GISTEMP.StationData

GISTEMP.StationData

KDM-IDL Code Library

I have spent quite a bit of time developing IDL code in the past, and it appears I will do some more in the near-term future. I have decided to release my IDL code library to the public so that others can perhaps benefit from my work. This is a work-in-progress and access is via Subversion.

One subset of the library is the KDM_KML lib for writing KML files. This code should make it fairly simple to display data sets in Google Earth from IDL.

I have currently implemented about 50% of the KML API and will get the rest implemented as time goes on. Right now layers can have overlays, points (placemarks), or linestrings (paths). Any element (that the API supports) can have a timestamp, and styles are supported too. With knowledge of the KML API you can create artistic balloons with whatever content you like that can even link to each other.

KML Interactive Sampler

If you create Google Earth or KML layers, you’ll want to find a 2nd monitor and keep the KML Interactive Sampler open full screen. An invaluable resource for hand-building a KML or when writing code.

KML Interactive Sampler

Geo-Tagging Photos

I have ~2700 photos from my recent trip to Antarctica. All but a few dozen were taken while on the ship, and the GPS track of the ship is known. The few that were taken off ship were within a three mile radius while deploying the ITP. If you don’t have a ship recording your GPS for you, you can get simple GPS systems for less than $100, or even a few $10s of dollars on eBay. The TrackStick is good for this type of project as it does not have a screen or realtime outputs.

I wanted to geotag all my photos by adding the latitude and longitude to the JPEG EXIF data. I was going to code it as the algorithm is quite simple (for each image, get the creation time, find the GPS location nearest that time in the GPS list, and add the (lat,lon) coordinates to the image), but not surprisingly this problem has already been solved. Repeatedly.

Three steps are required.

1. Convert your GPS data into GPX format. If you are comfortable on the command line then use gpsbabel. If not, then go here for a web interface to gpsbabel. If you need help post in the comments. If you were on NBP09-01 a GPX file of our cruise is here.
2. Add the GPS coordinates to the image EXIF tags. There are many tools that will take a GPX or NMEA file and add latitude and longitude coordinates to your photos. I use gpicsync and photoGPSEditor looks nice too.
3. Output KML files. gpicsync does this for you, and has a list of other software that might help here. You can also upload your photos to Picasa and get a KML file that way (instructions).

The end result might look like this.

Photos from Antarctica

If you’ve been following this blog you’ve seen a dozen or so low-quality photos posted during my trip. Now you can see full resolution pictures. In total, I took 2718 photos during the 54 days between when the Nathaniel B. Palmer (NBP) left Punta Arenas, Chile and returned. I’ve selected 350 of the best ones and uploaded them. There are 31 from the sea ice science projects, 54 of the NBP itself, 66 of animals (added to the animal photos from last year), 101 of the Pine Island Glacier, and 98 miscellaneous photos of the Amundsen and Bellingshausen seas, sea ice, sunsets, and sunrises.

You can view all of the photos listed above in the various Antarctica photo albums, or you can view them all geospatially (KMZ) in Google Earth. The ship recorded GPS a few times a second, and I have a one-minute (temporal) resolution data file that I used to geotag the photos.

Notes: If you are viewing the photos on the website, you ought to have the Cooliris plugin installed. Load times might be a bit slow, this computer is hosted at home. If you don’t see any photos in Google Earth you’ll need to drag the time slider to the right. They’ll pop up as you pass the time they were taken.

NBP Photos Geotagged in Google Earth