Posts
  • Isaac @ MSDN

    SQL Server Spatial Support: An Introduction

    • 32 Comments
    I’ve been pretty quiet around here, and at least part of the reason is that we’ve been pretty tight-lipped about what we’ve been up to. We’ve now gone public—we’re providing support for geospatial data in our next version of SQL Server, codenamed Katmai...
  • Isaac @ MSDN

    Eye Candy of the Highest Order

    • 24 Comments
    Hi Folks, One of the most common questions about the spatial support in SQL Server is how to visualize results. To illustrate the problem, consider a query over zip code data: select id, shapegeog from zipcodes where id like '981%' The results...
  • Isaac @ MSDN

    Latitude-Longitude Ordering

    • 16 Comments
    Hi Folks, If you've been following the spatial forum over at MSDN, you've probably run across this thread . In short, we've ignited quite a controversy with the coordinate ordering for the well-known text and well-known binary we use for the geography...
  • Isaac @ MSDN

    Nearest Neighbors

    • 16 Comments
    Hi Folks, Spatial users often want to find the object nearest a given point. This operation, usually referred to as nearest neighbor search , is remarkably common in many areas of computer science. In general, we may wish to find not only the nearest...
  • Isaac @ MSDN

    Spatial Data Type Structure

    • 14 Comments
    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...
  • Isaac @ MSDN

    The Upcoming Geography Coordinate Order Swap---A FAQ

    • 14 Comments
    Hi Folks, I just thought I'd take a few moments clarify the upcoming coordinate order swap for the geography type. Here's a quick FAQ on the issue: What exactly is the change? We are swapping the coordinate order for well-known text (WKT) and...
  • Isaac @ MSDN

    One Type, Two Types...

    • 10 Comments
    This is a little bit less of an introductory post than the last one , but there was quite a bit of discussion about our decision to split our spatial types in two---one for our planar ("flat-Earth") model and one for our ellipsoidal ("round-Earth") model...
  • Isaac @ MSDN

    Is my spatial index being used?

    • 10 Comments
    I've seen a problem commonly phrased something like: I have X million records in a spatial table, and have created a spatial index, yet a simple select query takes me Y hours to complete. Ouch! If the problem is this extreme, the solution is usually pretty...
  • Isaac @ MSDN

    PDC and a Nice Geographic Puzzle

    • 9 Comments
    Hi Folks, At PDC I gave a talk largely inspired by topics raised here and in the spatial forums.  But “inspired by” doesn’t equate to “a duplicate of”, and to turn things around, I’ve been meaning to write a few posts here inspired by my PDC talk...
  • Isaac @ MSDN

    Our Upcoming Builder API

    • 9 Comments
    Hi Folks, We have one more upcoming pre-release before we're done with SQL Server 2008, and while I've posted a few articles about the coordinate order swap, there's another exciting piece we're releasing: our builder API. Let's say you wanted to write...
  • Isaac @ MSDN

    After the Webcast

    • 8 Comments
    I had a few technical problems with the webcast that pushed our start time back about five minutes, but after switching to a different machine things went fine. I'm now recorded and online here . I generally don't like giving these webcasts, as I find...
  • Isaac @ MSDN

    Get yer spatial!

    • 7 Comments
    I'm happy to say that our latest community technology preview (CTP), officially dubbed the "November CTP" for obvious reasons, has been released. You can get it here . This CTP has all of the spatial funcitonality we've been talking about: Planar...
  • Isaac @ MSDN

    Spatial Indexing Part 1: Why a Spatial Index?

    • 7 Comments
    Hi Folks, If you've seen one of my recent spatial talks, you've seen me walk through the basics of how our indexing works. I'm going to do roughly the same thing here over a series of blog posts, except that I'm (eventually) going to go into a few...
  • Isaac @ MSDN

    The Imprecise Nature of Geometry

    • 6 Comments
    Hi Folks, Let's kick this off with what may be a surprising result.  What should this code return? declare @g geometry = 'LINESTRING (0 0, 1 3)' declare @h geometry = 'LINESTRING (0 3, 2 0)' declare @i geometry = @g.STIntersection(@h).ToString...
  • Isaac @ MSDN

    Frequently Asked Question: How do I load shapefiles?

    • 6 Comments
    This has come up a few times now.  Multiple questions deserve at least one answer, right? First, Microsoft has not produced a shapefile loader (or exporter).  If this is important to you, here’s the Connect item to hit.  (And yes: we do...
  • Isaac @ MSDN

    Spatial Indexing Part 2: A Simple Spatial Indexing Scheme

    • 5 Comments
    Hi Folks, Let's continue with the discussion of spatial indexing form last time . If you already know a lot about spatial indexing these first few posts are going to be a lot of background---hopefully I don't make too many mistakes. :) We're going...
  • Isaac @ MSDN

    Evaluation Order

    • 5 Comments
    A common general SQL question just popped its head up in the Spatial Forum : when presented with a SQL query, in which order are the parts executed? To be concrete, consider the following table and query: T: x 0 ...
  • Isaac @ MSDN

    In or Out?

    • 5 Comments
    I've been stalling, trying not to say too much about spatial until it's actually available. The code has all been in for some time now, but its been waiting for its release vehicle: the next CTP. Hopefully it should be in your hands in a few weeks. ...
  • Isaac @ MSDN

    More on the Multi-Level Grid

    • 5 Comments
    Hi Folks, In my last indexing post , I filled in most of the details about our multi-level grid index. Let me clean up a few lingering questions about our planar grid. We'll do this Q&A style: Q: What happens if I set the maximum number...
  • Isaac @ MSDN

    Connect and Implicit Casts

    • 4 Comments
    Hi Folks, Perhaps it is surprising, based on the content here, that I'm not a full-time spatial head here in SQL Server land. (We leave that job to Ed .) I have, of course, been spending a lot of time on spatial, but it turns out I have other responsibilities...
  • Isaac @ MSDN

    Picking up on Indexing: Moving Beyond the Simple Grid

    • 4 Comments
    Hi Folks, Well, I never did complete my series of posts describing our indexing scheme. I guess I ought pick it up again now. We've gone through some preliminaries so far, describing why we'd like spatial index , what a simple indexing might look...
  • Isaac @ MSDN

    Spatial Indexing Part 3: Faster Primary Filtering

    • 4 Comments
    Hi Folks, Last time we talked about a simple primary filter. (See previous installments: 1 , 2 .) We stopped short, however, of showing how this primary filter would actually make anything faster. Recall that our simple grid index defines a table...
  • Isaac @ MSDN

    At long last, a post: Medians in T-SQL

    • 4 Comments
    Well, shoot. Start a blog and then never post to it---not the best use of bits. I can't promise that this will be the beginning of a post-filled revolution, but it will hopefully be of some use. Assume you have a schema like: sales(city varchar...
  • Isaac @ MSDN

    Making Change

    • 4 Comments
    Raymond Chen has a post today about making change, which reminded me of an interesting problem. American currency (or most currencies, for that matter) has the desirable property that the greedy solution to giving change results in giving change using...
  • Isaac @ MSDN

    The Spatial Library without the Server: Bug and Workaround

    • 4 Comments
    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...
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