Spatial Data Type Structure

Hi Folks, As part of a larger effort to document our protocols, SQL Server has just released documentation on the structure of our spatial types.  The document is also available in PDF.  Note that all of this is preliminary, and while I doubt it will change much, it could.  I had very little to do…

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The Sphere is Finite

Hi Folks, The title of this post states the obvious: the area of a sphere is finite.  We even have a nice formula for it, 4πr2.  The same is true for an ellipsoid, which is just a sat-upon sphere, although computing the area gets more complicated. But the plane is infinite.  If we combine this…

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New Stuff in SQL Spatial Tools

Hi Folks, Marko Tintor from our Serbia team just dropped some new functionality into the SQL Server Spatial Tools project on CodePlex: A method for testing whether a geography instance is valid. Better: a method for creating a valid geography from invalid input.  How this works deserves a post on of its own, but it…

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The Plane, the Sphere, and the Ellipsoid

Hi Folks, We all know that the sphere isn’t the plane, and that an ellipsoid is different as well, but I don’t know if everyone has given so much thought to the practical effects of these differences. And so I thought it might be a nice idea to catalog some of the interesting things that…

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SQL Server Spatial Indexing

Hi Folks, This post contains no new information; it’s just a rollup of links to spatial indexing posts I’ve made.  If you want to know more about spatial indexing, these are the ones to read. In order: Why a Spatial Index? A Simple Spatial Indexing Scheme Faster Primary Filtering Picking up on Indexing: Moving Beyond…

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London Spatial Event

Simon Sabin asked me to pass along information about a free spatial event that he and Johannes Kebeck are holding in London on the 16th.  It looks like they’ll be covering a bunch of hot SQL Server Spatial topics: how to get your data in to SQL, how to get your data out and visualize…

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The Spatial Library without the Server: Bug and Workaround

Hi Folks, Jason Follas recently ran across a lingering issue when using our spatial library without the server.  I mistakenly thought the fix had been shipped, but for now it remains. The background is that the spatial library consists of a managed part and a native part.  Roughly, the core geometry library resides in the…

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The Geography Hemisphere Limitation

Hi Folks, It occurs to me that I haven’t posted anything about the hemisphere limitation for the SQL Server geography type.  This limitation is a little confusing, and could probably use some clarification. It also occurs to me that I haven’t posted anything in a while—let’s rectify both of these. We usually express SQL Server’s…

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