Archive for the 'Marin County' Category

Jun 22 2009

My Second Life tier will soon be history

Sometime, it just isn’t worth it. Such is my new view of tier, in the context of what matters to me with immersive 3D and GIS. For about six months I’ve continued my hold on some land in the classic Stanford sim of Second Life, without quite being able to work out the boundary changes to just barely squeeze in a 1:1 scale model of a single large building. Even if I had been able to get the parcel into the shape that I needed, I still would not be able to model the structure’s dome with a prim that naturally had the large radius required. Not everyone is trying to model a Frank Lloyd Wright public building; perhaps the land can be better used by someone else with an architectural focus.

I’m scaling back ownership this week to the tier-free 512 square meter level in Second Life. I’m also building up a freshly configured Ubuntu 9.04 Jaunty Jackalope 32-bit server (dual 3.4 GHz Xeon – 4 GB, HP DL360 G4) to do some more serious sort of work with OpenSim. In the past five months I’ve developed some terrain data that can handily provide 1-meter postings over more than 500 square miles. With that much to publish, I really need much, much more than 1/8 of a sim, even a suberbly cool sim like Stanford.

View of beautiful Stanford sim with pond features

View of beautiful Stanford sim with pond features

The orange area is available at L$20/square meter

The orange area is available at L$20/square meter

So if anyone reading this has use for a great 7520 (< 1/8 sim) mainland location in Second Life with over 40 meters of terrain sculptability, it’s available for L$20/square meter. Discount available for OpenSim community members or known GIS people. With the world’s economy as challenged as it seems to be, I’ve decided that it’s time to focus on where things matter most, and for me now that’s OpenSim more exclusively.

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May 24 2009

Some thoughts on geography

updated 2009 05 26

I’ve been waiting for some property boundary issues to resolve in SL, and it’s sort of pitiful to see how long that can take.  It’s with ever more regret that I find myself on the Mainland.  But that hasn’t kept lots of real-world interesting stuff from taking shape.

The following video is not new.  In fact it’s about a year old, but somehow I hadn’t seen it until tonight and I found it somewhat encouraging. Thanks for O’Reilly and Where 2.0 for bringing these two on stage together!

And the following pean to Google Earth did inspire me, personally. Hey, I was reading road maps at 5, covered my wall completely with National Geographic maps at 10, learned to navigate with nautical charts at 12, read aeronautical charts and completed an urban planning project at 14. Sometimes, it’s fun in rare moments when it’s dark overcast and I’m in an exotic place for the first time and I don’t know the way north; more often, I’ll savor the feeling of knowing which way is north while dreaming.

Meanwhile, back at the lab, the global set of county terrain is being compiled into an ESRI Terrain Dataset. This will include over 360 million masspoints, merging both interpolated 2-foot interval contour vertices together with FEMA LiDAR mass points, plus break lines and waterlines from photogrammetry. The goal is to use the ESRI Terrain data as a format to stage everything together to produce 30cm grid interval DEM in the urban areas. With luck, we’ll have that ready about the time that the latest photo mosaic finally gets loaded into ArcSDE successfully. Maybe grids from the Terrain can help create very detailed 3D county models. Hey Wei – we still have inverted terrain in Google Earth at the quarry on San Pedro Point! ;^)

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Mar 25 2009

Terrain Tenacity, fresh ortho pixels

Terrain has been in the mix for me quite a bit these past four weeks.  I’ve worked on pushing ESRI ArcGIS 3D Analyst to its limits of masspoint digestibility, trying hard to bring everything into focus at the same time that everything is sinking down to NAVD88 datum.  An abundant set of waterlines and terrain breaklines have helped to make possible some terrain models that appear to be as good as any one is likely to get from photogrammetric data.  As with LiDAR source, I’m working toward a 30cm gridding interval to sample any reasonable-looking TIN models.

One fascinating aspect of the terrain model is where it ends.  There appears to be a new 1:1200 or 1:4800 shoreline that can be sussed out of some combination of 2.5-foot elevation waterlines, 2-foot elevation contours, and related artifacts.  In fact, it’s a great patchwork of artifacts that must be stringed together.  In the tidal flat areas, there is also plenty of need for validation with multiple photos (hopefully shot at times of lower tides).

Adding to the data bulk there’s a new ortho in town, 30cm natural color flown just about two years ago.  There’s hope of extracting it from the grip of California HARN coordinates after it is all mosaicked.

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