Archive for the 'Blog mentions' Category

Jun 25 2014

Open Simulator joins the SGeoS build — a strategy for blogging the builds

This is the first of what should be  a set of posts that detail a server build process for the San Francisco Enterprise Geographic Information Systems Program (SFGIS) Standard Geospatial Server (SGeoS).  In fact, the build work has been ongoing for several weeks and is concluding here, with OpenSim.

The motivation for including OpenSim in the platform was a desire to provide support for legacy .NET applications that may exist in various departments. In the interest of creating a Microsoft-neutral build that is framed with Open Source components, it was natural to bundle the Mono framework into the SGeoS design.  And while individual department applications are their own business and not part of the standard build, OpenSim serves as an excellent demonstration of the utility of the Mono framework as included on the server.  That , together with my perspective that immersive 3D clearly should be associated with geospatial servers, is why OpenSim is included in the Standard Geospatial Server.

OpenSim is not trivial by any means, and yet it is not such a resource hog that it would be infeasible to bundle it.  What’s more, it is an opportunity to distribute immersive 3D technology packaged with other geospatial capabilities.

Since the build descriptions are being transcribed from a build document that is approaching 80 pages on Google Docs, it seems prudent to break it up into individual modules.   And since WordPress here is configured to show older posts below newer ones—I’ll start down at the end modules and post new build descriptions for earlier modules in later days.

The original notion for SGeoS was to have modular build chapters that could provide a unit of capability.  That way, only selected modules need be configured.  After discussions with VMware engineers, I became intrigued by the notion of making a single server image that could run everything, all at once, and then disable unneeded featured in an actual deployment.  So the build document was initially structured with module-like chapters, but in fact the server builds them all—so it’s worth viewing the build document in sequence.

The modules will probably end up  numbering about 10, including packaging for production and possibly default-disabling of most items.   If one watches too closely, it might seem like I’m making a countdown to completion.  But this will end with a stub for deployment packaging, work back through an OpenSim build, and end up with imaging an install of CentOS 6.5 onto a new VM guest system.

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Oct 30 2010

Tied up in knots with Spatial SQL

The rules for geometry validation are just different between the ESRI world and the OGC world as instantiated by Microsoft in SQL Server 2008 R2.
I’ve been pounding my head against the wall over what I thought were the challenges of taking fine examples from Alastair Aitchison (a.k.a. tanoshimi on the MSDN forums) that are presented in Beginning Spatial with SQL Server 2008, and trying to make these happen in useful ways on real GIS data.  That is to say, data that were not created by hand-entry or even well-known-text (WKT) entry into SSMS, which are often  simple single features.

I was particularly concerned reading the first paragraph in Chapter 11: “All of the techniques discussed in this chapter apply only to a single item of geography or geometry data, and generally do not require any parameters.”  As I understand now, Mr. Aitchison meant “All of the techniques as discussed…” and all the various Spatio-Temporal methods like STIntersects() work perfectly well on perfectly valid spatial tables.

I thought that these methods just weren’t going to work on my GIS data,  typically large tables with lots of objects, not the scalar objects of the book examples.  But as it turns out, I had a different problem.  My geometry, as transcribed via Shapefiles and the Shape2SQL tool from SharpGIS.net, was arriving in a form that was occasionally invalid for certain features.  One invalid feature in a spatial table makes the entire SQL statement crash.  Errors were reported with reasons that did not help me find my actual problem very easily.  Bad geometry meant that I needed to clean it up by running the MakeValid() method.

After a couple of hours goofing around with T-SQL syntax, I’ve made my first baby steps toward cleaning up my stuff.  Here’s how that is happening:

(select ID, PARCEL, Prop_ID, Shape_area, Shape_len, (CASE Shape.STIsValid() WHEN 1 THEN Shape ELSE Shape.MakeValid() END) as Shape INTO spatial_01.dbo.Parcel2 FROM spatial_01.dbo.parcel)

As so often with code, it looks stupid-simple to see it written out in the way that actually works; a major “duh” factor.
The pay-off is that with 100% valid geometry, table vs. table spatial queries are now working.  I’ve not yet broken any speed records in query performance vs. ArcGIS 10, and yet I have finally proven to myself that I can use  Spatial SQL to do powerful geoprocessing that, in some cases, will be easier to write and maintain in SQL than in ArcGIS / Model Builder / Python.

For context, I’ve struggled through the past four days trying to figure out where my Spatial SQL syntax was messed up.  As it turned out, exactly ZERO of my uploaded spatial data tables arrived with 100% valid GEOMETRY data.  Anyway, once I made everything OGC-valid, a query like this

SELECT NAME, b.PType INTO spatial_01.dbo.School_Geology
FROM spatial_01.dbo.school2 a, spatial_01.dbo.geology2 b
WHERE a.Shape.STIntersects(b.Shape) = 1
Is really all it takes to return the mapped geologic unit beneath the point for every school in the county.
For 120 school points, and 3700 geology polygons, the query above returns its result in about 30 seconds, with no tuning of the spatial indices and no SQL hints provided (yet).
"NAME","PType"
"TOMALES HIGH SCHOOL","Twg"
"BOLINAS-STINSON SCHOOL (STINSON)","Kfs"
"LAGUNA JOINT ELEM. SCHOOL","Qal"
"SAN GERONIMO VALLEY ELEM. SCHOOL","fsr"
"LAGUNITAS ELEM. SCHOOL","fsr"
"MARIN HORIZON SCHOOL","fsr"
"COUNTY COMMUNITY SCHOOL","Qal"
"ST RITA SCHOOL","Qal"
"ST PATRICK SCHOOL","fsr"
...

On a last note, this week I have validated the experience of using ESRI ArcSDE 9.3.1 settings to configure SDE (when running atop MS SQL Server 2008) to store its geometry in native OGC GEOMETRY binary form rather than the classic SDEBINARY form.  To do this, someone with db owner privileges can update the SDE_dbtune table with these directions to cause the GEOMETRY format to be used by default.  In principle, this should allow one to exploit the live feature classes in SDE for Spatial SQL queries—without the muss and fuss of exporting through Shapefiles and Shape2SQL (which is not intended for production-environment use, anyway), or need to code something in .NET to export a copy.

Wouldn’t it be nice to have ArcSDE running just like it always has, and then also be able to use Spatial SQL queries on the exact same feature classes that are being used throughout the enterprise?  Sounds great, in principle.  After tonight’s insight into the need to MakeValid() some perfectly functional feature classes, I do have some concerns that SDE feature classes could get broken by MakeValid().  On the other hand, it appears that one can take a Spatial SQL GEOMETRY-based table that meets SDE limitations: (1) only one geometry column, (2) all rows of the table must have the same geometry type, (3) all rows of the table must have the same Spatial Reference ID (SRID) defined—and any SDE feature class that was cleaned through MakeValid() should retain those characteristics—and then register the resulting spatial SQL table once again as an SDE feature class.  Hey, it sounds like it’s worth a try!

More working through Aitchison’s book has yielded many successful uses of OGC methods on our GIS data:

-- SELECT Shape.STGeometryType() FROM [spatial_01].[dbo].[road]
-- SELECT Shape.STGeometryType() FROM [spatial_01].[dbo].[Parcel]
-- SELECT Shape.STGeometryType() FROM [spatial_01].[dbo].[school_pt]
-- SELECT Shape.STGeometryType() FROM [spatial_01].[dbo].[geology]

-- SELECT Shape.STDimension() FROM [spatial_01].[dbo].[geology]
-- SELECT Shape.STDimension() FROM [spatial_01].[dbo].[road]
-- SELECT Shape.STDimension() FROM [spatial_01].[dbo].[school_pt]

-- SELECT Shape.InstanceOf('Surface') FROM [spatial_01].[dbo].[geology]
-- SELECT Shape.InstanceOf('Polygon') FROM [spatial_01].[dbo].[geology]
-- SELECT Shape.InstanceOf('Curve') FROM [spatial_01].[dbo].[road]
-- SELECT Shape.InstanceOf('LineString') FROM [spatial_01].[dbo].[road]
-- SELECT Shape.InstanceOf('Point') FROM [spatial_01].[dbo].[school_pt]

-- SELECT Shape.STIsSimple() FROM [spatial_01].[dbo].[road]
-- SELECT Shape.STIsSimple() FROM [spatial_01].[dbo].[BldgFoot]

-- SELECT Shape.STIsClosed() FROM [spatial_01].[dbo].[BldgFoot]

-- SELECT Shape.STIsRing() FROM [spatial_01].[dbo].[road]

-- SELECT Shape.STNumPoints() FROM [spatial_01].[dbo].[road]
-- SELECT Shape.STNumPoints() FROM [spatial_01].[dbo].[geology]
-- SELECT Shape.STNumPoints() FROM [spatial_01].[dbo].[school_pt]

-- Find Centroids and blob them out big
-- SELECT Shape.STCentroid().STBuffer(3500) FROM [spatial_01].[dbo].[City]

-- Calculate Perimeter Lengths and sort them out
-- SELECT Shape.STLength() as Shape_len FROM [spatial_01].[dbo].[City] ORDER BY Shape_len

-- Calculate City areas and sort them out
-- SELECT NAME, CAST (Shape.STArea()/1000000 AS INTEGER) as Shape_km2
--   FROM [spatial_01].[dbo].[City] ORDER BY Shape_len
-- Reading the SRID
-- SELECT Shape.STSrid FROM [spatial_01].[dbo].[City]

-- Setting the SRID
-- UPDATE [spatial_01].[dbo].[City] SET Shape.STSrid = 32610
-- SELECT Shape.STSrid FROM [spatial_01].[dbo].[City]

-- oops, that's wrong, let's set it back to 2768
-- UPDATE [spatial_01].[dbo].[City] SET Shape.STSrid = 2768
-- SELECT Shape.STSrid FROM [spatial_01].[dbo].[City]

-- counting elements
-- SELECT SUM(Shape.STNumGeometries()) FROM [spatial_01].[dbo].[City]
-- SELECT SUM(Shape.STNumGeometries()) FROM [spatial_01].[dbo].[school_pt]
-- SELECT SUM(Shape.STNumGeometries()) FROM [spatial_01].[dbo].[geology]
-- SELECT SUM(Shape.STNumGeometries()) FROM [spatial_01].[dbo].[road]
-- SELECT SUM(Shape.STNumGeometries()) FROM [spatial_01].[dbo].[Parcel]
-- SELECT SUM(Shape.STNumGeometries()) FROM [spatial_01].[dbo].[BldgFoot]

-- Geometric Difference between cities and their own 3500-meter centroid blobs
-- SELECT Shape.STDifference(Shape.STCentroid().STBuffer(3500)) FROM [spatial_01].[dbo].[City]

-- Geometric Symmetric Difference between cities and their own 3500-meter centroid blobs
-- SELECT Shape.STSymDifference(Shape.STCentroid().STBuffer(3500)) FROM [spatial_01].[dbo].[City]

-- Creating 50-foot Buffer around roads
-- SELECT Shape.STBuffer(50) FROM [spatial_01].[dbo].[road]

-- Simplified Buffer around roads, tolerance 8 feet
-- SELECT Shape.BufferWithTolerance(50, 8, 'false') FROM [spatial_01].[dbo].[road]

-- Create convex hull around schools
--SELECT Shape.STConvexHull() FROM spatial_01.dbo.school_pt

-- buffer parcels
-- SELECT Shape.STBuffer(300) AS Shape INTO pcl_seed FROM parcel where Prop_ID = '001-001-01'
-- select * from pcl_seed  -- to verify the selection
-- SELECT Prop_ID, a.Shape FROM spatial_01.dbo.parcel a, spatial_01.dbo.pcl_seed b
--   WHERE a.Shape.STIntersects(b.Shape) = 1

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Feb 04 2010

A visit to ScienceSim Geography regions – OpenSim with turbo boost

I don’t have much to say about these regions that hasn’t been written already, and my views have been less aesthetic than Shenlei’s.
But in the interest of boosting the bandwidth by which I can share OpenSim, I’ve invested in a much newer Adobe Premiere Elements than I’d been using for the past five or so years. It’s a gas to have it multi-thread while rendering, and I have direct-to-FLV write. Trying to share as much of the motion and fidelity via YouTube as I possibly can, I’ve crafted a video resolution that is a multiple of my Hippo / SL viewer screen. The FRAPS video direct to AVI (sorry, it’s Win XP) is 1600 x 1140 @ 10 fps. Yup, those are video frames. In the interest of surviving an upload, I’ve rendered them highly time-compressed, with output at 1515 x 1080 @ 15 fps. As of tonight there’s no sound, no intertitles, just the rushes.
oops, if I read the YouTube Instructions for best formats, I should have trimmed the width to 1440, which is a multiple of 16.
Also, I have more direct upload options now with Premiere 8 than I had with my (recently demised) copy Premiere 1.0. Go Figure ;^)

While the Windows box grinds out the video print, I’m over here on Ubuntu blogging in a tab of 64-bit Chrome 4.0.249.43 and it is fine & fast.

For these videos, I visited ScienceSim Geography22_44 region and set the view to wide angle, then sat up at about 500 meters and watched the regions rez their terrain. For some folks, it will rank right up there with watching lead-based paint dry. For geography folks I’m hoping that these few minutes of sped-up video will convey, by dogged repetition, the primacy of regions in the provision of virtual environment simulators.

By the way, I’ve got a task: I need to find a better buzz word for the GIS community. I’ve been advised by some serious and well-intentioned (not to mention well-informed) folk that terms like “virtual” and “immersive” are actually boring to GIS’ers. So I’ll need to think about how to convey the concepts of “Mirror World”, “Multiuser Virtual Environment”, “Immersive Connected Experience”, “Third-Person Virtual World”, and related concepts into a catchy moniker. Hopefully, one that is not presently trademarked, either!

I’m trying to remain serious about this, but some of the options are treacherous. Geography in Social Media has a possibly awkward acronym; maybe it can be saved in recognizable form as “GIS for Social Media” or “Geography for Social Media”: GFSM
The term “3D Map with Me” is terse, slightly ambiguous

Here is the video chopped as it was when uploaded with 1515 x 1080 resolution. Problem with that is that by not preserving dimensions at a multiple of 16, and saving my viewer’s aspect ratio rather than the (standard since 16mm film) 4:3 aspect, my upload is clobbered into something perhaps suitable for a smartphone. So please consider this the Smartphone Version of last night’s rushes:

Then, once again with feeling, or at least with a little more rest, there is what I hope to be an HD-friendly moving vision of OpenSim, as it appears on the ScienceSim Geography regions. Yes! After it ripened on the YouTube servers for a few hours, I now see all the higher-res versions available. At 1440 x 1080, this is pretty close to what I see on my screen with a live Hippo viewer.

And after a day’s cogitation: anyone care to comment on the term: “Social Immersive Media GIS” as a moniker? Oops — I used “immersive” 8^(

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Jan 22 2009

3D Geospatial Day at BAAMA.org

Today the (San Francisco) Bay Area Automated Mapping Association hosted a wonderful URISA Certified Workshop given by Tim Case, describing Best Practices and Project Implementation Methods for 3D Geospatial work. The all-day event provided a very broad and even-handed overview of many 3D technologies that hold promise for the near future.

With this presentation as an extra boost for my focus on a new build, I’m gearing up with even more enthusiasm for a new build in the Agni grid Mainland.  I’ve also tuned the Berkeley parcel for sale.  Its price amounts to about US$382.00, and that price is set to help cover purchase costs for the next build’s likely parcel.  The tuning involved reducing the parcel size by 64 square meters, so that the three Gualala parcels total 4608 square meters, or exactly the maximum amount allowed for Linden Lab’s US$25/month tier rate.  With that size, it would be possible for an interested party to purcahse the Berkeley BART station and maintain it for $300/year in tier (the Linden land property tax).

Also, based on today’s Geospatial tag, I’ve noted just this morning two mentions of the Berkeley BART build.  The New World Notes item by Wagner James Au 2009 01 19 was wonderful to find after our in-world messages last month.  For clarification, while true at the time of that conversation, no longer do I work for City of Berkeley.  The TidalBlog item by Peter Miller mentions interesting developments in the overlap between simulators and geospatial models, as well as some shots from his visit to the Berkeley BART model.  Thanks to both authors for their posts!

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