Postgres OnLine Journal - gis

PostGIS In Action 2nd Edition MEAP 3 Update

nospam@example.com (Leo Hsu and Regina Obe) — Fri, 05 Apr 2013 19:06:00 -0400

The 3rd MEAP update of PostGIS In Action, 2nd Edition will be going out very shortly to Early Action purchasers. Keep your eyes peeled. Lots of errata corrections in previous chapters and appendix, and one very VERY new chapter on Raster functions which took a ton of time to write, so hopefully it will be well received. Our progress on the chapters is listed on PostGIS In Action 2nd Edition Chapters and all the ones marked as completed you will find in the MEAP. The ones with paperclips have downloadable code and data which you can click on the paperclip to download.

Regarding Raster, the Raster Function chapter is just merely the tip. You'll see a lot more raster usage in upcoming Relating two or more spatial objects and Raster Processing chapter which we are still fleshing out.

We are immensely grateful to all the early action subscribers who have posted errata or general comments about what can be clarified or examples that don't work. General comments about what specific kinds of examples you'd like to see are also welcome. Your opinions really influence what we write and make for a better book.

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Boston OSGeo Code Sprint Highlights

nospam@example.com (Leo Hsu and Regina Obe) — Thu, 28 Mar 2013 21:42:00 -0400

Today was the last day of the Boston OSGeo code sprint we hosted. Several OSGeo project tribes were represented. PostGIS had a big showing with core PostGIS developers and related working on PostGIS core, PostGIS 3D, PostGIS raster, pgRouting, geocoding, and point clouds. Leo and I with lots of help from Steve Woodbridge, spent a good chunk of time working out kinks of PostGIS pgRouting packaging for Windows and address normalizer replacement for the one packaged with tiger geocoder.

A special shout-out thanks to all the Code Sprint sponsors:

Gold: EnterpriseDb
Silver: GeoSynergy, Airborne Interactive
Bronze: Hobu, Azavea, OneOcean, and AppGeo

More details Paul's PostGIS Summary and Paul's MapServer Summary and our Boston OSGeo Code Sprint Synopsis.

PostGIS in Action 2nd Edition reaching MEAP soon

nospam@example.com (Leo Hsu and Regina Obe) — Thu, 13 Dec 2012 22:49:00 -0500

We just finished the first draft of the first 5 chapters of the second edition of PostGIS in Action and is slated to be added to Manning's Early Action Program (MEAP) in the next 2-3 weeks. Some people have asked us about this when they can start purchasing the new edition. The new edition is purchaseable as soon as it hits MEAP phase. With a MEAP purchase you get the E-Book drafts as soon as they are available and if you buy the MEAP with hard-copy option, you also get the final hard-copy when released. MEAP is the same price as the regular book except it can only be bought direct thru Manning and it gives you access to early content so you can see all our mistakes and cross outs as things change.

We shuffled some of the chapters a bit from our earlier table of contents, but in these first 5 chapters you'll be exposed to new features in PostGIS 2.0, the more modern way of creating spatial tables, utilizing the new raster and topology types, and also find out about the new great stuff coming in PostGIS 2.1 that is already available in PostGIS 2.1 pre-release. More on that in the coming weeks.

What is coming in PostGIS 2.1 that you don't want to miss? Lots. Check out our Waiting for PostGIS 2.1 series and also a list of Duncan Golicher's highlights, which Pierre Racine has kindly outlined in Duncan Golicher's series of PostGIS articles

PostGIS 2.0.0 is out

nospam@example.com (Leo Hsu and Regina Obe) — Tue, 03 Apr 2012 20:58:00 -0400

Yap that's right. PostGIS 2.0.0 is finally out the door. It took us Two years and 2 months, a super long incubation for us, but we did it and just in time for Javier's Where 2.0 2.0 Talk.. Paul has some border-line R rated pictures of the birthing process.

We have windows 32 binaries posted for those adventurous enough to taste the cookies while they are hot. We are working on the windows 64-bit binaries. Those should be out tomorrow. We'll be working in the coming week to get the installers ready to put up so they are available via Stack Builder. We'll probably put up the 32-bit ones first, hopefully followed shortly by the 64-bit ones. You should see PostGIS 2.0.0 soon on Yum as well. Devrim is cooking :).

PostGIS 64-bit for Windows it's coming

nospam@example.com (Leo Hsu and Regina Obe) — Sat, 10 Mar 2012 03:46:00 -0500

UPDATE We have PostGIS 2.0.0 available for both 32-bit and 64-bit windows PostgreSQL. We are wroking on getting the installers out

This past week has been very nerve racking but also exciting. We have successfully compiled PostGIS under the mingw64 chain and built a PostGIS windows 64-bit for 2.0 (and 1.5), that can install under the Enterprise Db VC++ 64-bit builds of PostgreSQL 9.1. We haven't tried on 9.0, but we assume that should be fairly trivial. Note only that, but it passes most of the PostGIS battery of tests. We first want to thank a group of people which made this all possible:

Andrew Dunstan we are greatly indebted to for making it possible to compile PostgreSQL under mingw64 tool chain. As much as people have whined about wanting to compile PostGIS under a pure VC chain, this is not possible at this juncture just because a lot of the tests and other tool chains PostGIS uses for building are too tied to the Unix build environment.
We want to thank the generous folks who provided money for our campaign so that we could funnel time from paid consulting work to focus on this effort and to prove that every little bit counts.
SpatiaLite developer Alessandro Furieri whose mingw64 compile instructions were invaluable to helping us overcome our GEOS and other compile obstacles. SpatiaLite (the OGC spatial extender for SQLite),uses much of the same plumbing that PostGIS uses under the hood, so many of the lessons he learned an provide could be put to use with our problems.
To Paul Ramsey especially and other PostGIS devs for general moral support and helping us tackle some PostGIS specific issues when compiled with mingw64. Paul demonstrated that yes you can mix VC++ built components with MingW and steps on how to do it. Part of the reason for that is the newer mingw32 seemed to crash with GEOS compiled under mingw32. Though the mingw64 chain didn't have this issue once we overcame our compile obstacle. We may in the future compare and see if compiling Geos under VC++ provides better performance and will also get us closer to having it possible to compile PostGIS fully under VC++ if people choose to. For the time being having a single tool chain that we can extract and run with is most important. We are preparing a self-standing Mingw64 tool chain with all the components needed to build PostGIS already compiled so that windows users who want to help with PostGIS need only extract to have a fully functioning postGIS dev environment and we also plan to move our mingw32 build to mingw64 chain of tools.

We hope to have a 64-bit compiled download ready next week for PostGIS 2.0.0 beta3 for people to try out. We are working on some issues with the raster2pgsql and loader/dumper guis we compiled not working right, but the core PostGIS works just fine in 64-bit and the 32-bit loader tools work fine against a 64-bit install. One thing we did notice with the 64-bit PostgreSQL is that we can set shared_buffers much higher than the 32-bit PostgreSQL windows. On windows we could never go beyond ~700MB without it not being able to start or crashing. With the 64-bit we were able to go to 2GB. Haven't tried higher yet. We hope this will prove to be a performance boost for tasks such as geocoding that reuse a lot of the same datasets and benefit a lot from share memory.

GeoInformatics article and new book in the works

nospam@example.com (Leo Hsu and Regina Obe) — Wed, 14 Dec 2011 22:56:00 -0500

Two exciting things happened this past month.

Our article on upcoming PostGIS 2.0 recently came out in GeoInformatics Magazine December 2011 Issue 8. Check it out here. Starts on page 30.
We just got notice that our book proposal has been accepted and this time it's not about PostGIS.

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Code Profiling with PostGIS raster

nospam@example.com (Leo Hsu and Regina Obe) — Sun, 04 Dec 2011 10:20:00 -0500

What happens when you take a bunch of auto-generated tests and test results which you burn into rasters with SQL? You get a code fingerprint of sorts. Well that was the dream I wanted to explore. Now that PostGIS 2.0 has introduced a new spatial type called raster and lots of functionality including some very cool Map Algebra functionality to go with it, this is now possible without too much fuss. My first attempt at it didn't produce quite what I expected. I have to admit it is absolutely gorgeous and will be hopefully useful once I figure out how to read it, tweak the rendering process to achieve more of a breakout of results, or patent it as a fabric style.

Now for the story of how a computer nerd is born and how rasters can be useful to nerds.

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XPathing XML data with PostgreSQL

nospam@example.com (Leo Hsu and Regina Obe) — Fri, 11 Nov 2011 03:57:00 -0500

One of my favorite tools and I think that of many folks working with GIS and other kinds of Multimedia is the GDAL/OGR suite. Though I started using it to conquer GIS ETL activities, I found myself using it for problems that are inherently not GIS at all. I talked about the GDAL OGR2OGR component a while ago in GDAL OGR2OGR for Data Loading and this time I'll talk tangentially about its raster capabilities. It is a fantastic tool for converting between various raster formats and applying various raster operations. In PostGIS world the new 2.0 raster functionality puts an SQL wrapper around much of its power. I'm not going to talk about that though except as a fleeting comment to explore later (we've got cool 2 band Map Algebra in PostGIS 2.0 to flaunt its stuff). So what does this have to do with XPathing XML data with PostgreSQL? Well that's what I'm going to talk about what to do with machine generated data that comes at you in XML format.

A lot of machine generated data is hitting us in an XML like form. I talked about GPX data and navigating that in Which by the way GDAL/OGR can load and export easily into/out of a PostGIS enabled database.

GDAL exposes another kind of machine generated data in XML format which turns out to be very useful for all kinds of things. This is Exchangeable image file format (EXIF) data. There are all kinds of random text information embedded in pictures and this varies depending on what camera is taking it. Newer cameras like the ones you have built into your iphone or android embed location based information into them sometimes like where you were standing when you took the picture. Most cameras these days embed the time the picture was taken. This information is important because if you are taking electronic notes while you are snapping your pictures, it provides an easy way to match up your notes with the picture about the object. So what does this EXIF info look like when you point GDAL at it? We'll see.

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Many PostGIS FOSS4G 2011 videos have landed

nospam@example.com (Leo Hsu and Regina Obe) — Fri, 28 Oct 2011 17:33:00 -0400

FOSS 4G 2011 Videos. My resident PostGIS developer strk says he can't see them because blip.tv is using some sort of proprietary video swf format. I can't really tell what he is talking about. Does anyone know if fosslic videos are available in other formats like ogg or a Gnash swf viewer compatible format?

We mentioned in prior article Our FOSS4G 2011 the new Stuff and provided the slides in that article. Now we have the video to go with it.

Here is a partial list of PostGIS videos:

Paul's standard State of PostGIS He ran out of time so our's is more like a continuation.
PostGIS 2.0 the new Stuff (our presentation)
PostGIS Raster 2.0 - store, manipulate and analyze raster Pierre Racine

Continue reading "Many PostGIS FOSS4G 2011 videos have landed"

Improving speed of GIST indexes in PostgreSQL 9.2

nospam@example.com (Leo Hsu and Regina Obe) — Wed, 12 Oct 2011 18:24:00 -0400

This is about improvements to GIST indexes that I hope to see in PostgreSQL 9.2. One is a patch for possible inclusion in PostgreSQL 9.2 called SP-GiST, Space-Partitioned GiST created by Teodor Sigaev and Oleg Bartunov whose basic technique is described in SP-GiST: An Extensible Database Index for Supporting Space Partitioning Trees. For those who don't know Teodor and Oleg, they are the great fellows that brought us many other GiST and GIN goodnesses that many specialty PostgreSQL extensions enjoy -- e.g. PostGIS, trigrams, ltree, pgsphere, hstore, full-text search to name a few.

Another is a recent one just committed by Alexander Korotkov which I just recently found out about on New node splitting algorithm for GIST and admit I don't know enough about to judge. I have to admit to being very clueless when it comes to the innards of index implementations so don't ask me any technical details. It's one of those short-comings among the trillion others I have that I have learned to accept will probably never change.

What the SP-GIST patch will provide in terms of performance and speed was outlined in PGCon 2011: SP-GiST - a new indexing infrastructure for PostgreSQL Space-Partitioning trees in PostgreSQL.

What it provides specifically for PostGIS is summarized in Paul's call for action noted below. As a passionate user of PostGIS ,ltree, tsearch, and hstore, I'm pretty excited about these patches and other GIST and general index enhancements and there potential use in GIST dependent extensions. I'm hoping to see these spring to life in PostgreSQL 9.2 and think it will help to further push the envelope of where PostgreSQL can go as a defacto platform for cutting-edge technology and scientific research. I think one of PostgreSQL's greatest strength is its extensible index API.

Paul's PostGIS newsgroup note about seeking funding for faster GIST indexes , work done so far on SP-GIST and call for further action is rebroadcast in it's entirety here.

Thanks to the sponsorship of Michigan Technological University, we now
have 50% of the work complete. There is a working patch at the
commitfest https://commitfest.postgresql.org/action/patch_view?id=631
which provides quad-tree and kd-tree indexes.

However, there is a problem: unless the patch is reviewed and goes
through more QA/QC, it'll never get into PostgreSQL proper. In case
you think I am kidding: we had a patch for KNN searching ready for the
9.0 release, but it wasn't reviewed in time, so we had to wait all the
way through the 9.1 cycle to get it.

I am looking for sponsors in the $5K to $10K range to complete this
work. If you use PostgreSQL in your business, this is a chance to add
a basic capability that may help you in all kinds of ways you don't
expect. We're talking about faster geospatial indexes here, but this
facility will also radically speed any partitioned space. (For
example, the suffix-tree, which can search through URLs incredibly
fast. Another example, you can use a suffix tree to very efficiently
index geohash strings. Interesting.)

If you think there's a possibility, please contact me and I will send
you a prospectus you can take to your manager. Let's make this happen
folks!

Paul

Continue reading "Improving speed of GIST indexes in PostgreSQL 9.2"

PostGIS as a graphical engine

nospam@example.com (Leo Hsu and Regina Obe) — Fri, 26 Aug 2011 18:50:00 -0400

A while back in New Additions and Promotions in PostGIS Development Team, I mentioned that the new addition to our team Bborie Park was working on image output functions for raster support, among other things. His last addition was ST_AsRaster which allows a PostGIS geometry to cross the line to the raster world, all in the database. This new addition almost completes the basic cycle of making PostGIS not only a spatial analytical tool, but also a rendering engine.

To test out these new functions, I whipped up a quick ASP.NET/JQuery app as described in Minimalist Web-based ASP.NET PostGIS 2.0 Spatial Geometry/Raster Viewer, and Bborie followed up with the PHP version which you can download from http://www.postgis.us/downloads/postgis_webviewer_php.zip.

There is still much room for improvement, e.g. intersection of 2 rasters, faster response, etc, but I can see all the lights flickering and the connections coming together like a self-orchestrating organism. From chaos comes order.

Free and Open Source Software for Geospatial - FOSS4G 2011- PostGIS galore

nospam@example.com (Leo Hsu and Regina Obe) — Wed, 24 Aug 2011 03:18:00 -0400

The Free and Open Source Software for Geospatial (FOSS4G) is schedule for September 12-16, 2011 in Denver, CO. PostGIS is going to be making a big showing at this event. Paul Ramsey's popular Introduction to PostGIS workshop is already sold out. Check out the schedule of other PostGIS related talks FOSS4G 2011 PostGIS related talks.

We'll be presenting on Friday PostGIS 2.0, the new stuff and showcasing some of the new features in upcoming PostGIS 2.0. In fact Friday seems to be a day jam packed with PostGIS talks back to back in the Windows room. We probably won't even have to leave the room to get our fill of PostGIS.

I'm particularly looking forward to Steven Singer's PostGIS replication talk and Jim Mlodgenski's Scaling PostGIS Queries with Stado since these are becoming critical areas as we take on larger and more complex work.

Using PgAdmin PLPgSQL Debugger

nospam@example.com (Leo Hsu and Regina Obe) — Mon, 27 Jun 2011 01:49:00 -0400

I'm one of those old-fashioned folks that debugs with print lines and raise notices. They're nice. They always work, you can put clock time stops in there and don't require any fancy configuration. At a certain point you do have to pull out a real debugger to see what is going on. This often happens when your one-liners are no longer good enough and now you have to write 20 liners of plpgsql code.

Such is the case with geocoding and the PostGIS tiger geocoder specifically. Lots of interest has revived on that with people submitting bug reports and we've got paying clients in need of a fairly easy and speedy drop-in geocoder that can be molded to handle such things as road way locations, badly mis-spelled real estate data, or just simply to get rid of their dependency on Google, Yahoo, MapQuest, ESRI and other online or pricey geocoding tools. So I thought I'd take this opportunity to supplement our old-fashioned debugging with plpgsqldebugger goodness. In this article, we'll show you how to configure the plpgsql debugger integrated in PgAdmin and run with it.

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Variadic Functions in PostgreSQL

nospam@example.com (Leo Hsu and Regina Obe) — Fri, 03 Jun 2011 22:02:00 -0400

PostgreSQL 8.4 introduced the ability to create user-defined variadic functions. These are basically functions that take as input an undefined number of arguments where the argument that is an undefined number are all of the same type and are the last input arguments. Depesz went over it two years ago in Waiting for 8.4 variadic functions, so we are a bit late to the party. In a nutshell -- variadic functions are syntactic sugar for functions that would otherwise take arrays. In this article we'll provide some more demonstrations of them to supplement Depesz article.

I was reminded that I had never explored this feature, when recently documenting one of the new PostGIS 2.0 Raster functions - ST_Reclass which employs this feature. I think ST_Reclass is a superb function and one of my favorite raster functions thus far that I hope to put to good use soon. Our new PostGIS family member,Bborie Park, is running thru our PostGIS Raster milestones much faster than I had dreamed. He's already implemented a good chunk of stuff we discussed in Chapter 13 - PostGIS Raster and had stated you probably won't see in PostGIS 2.0. He's going a bit faster than I can catalog them, so the documentation is already embarrassingly behind the fantastic functionality that is already present in PostGIS 2.0.

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PgCon 2011 Notes recap and more notes

nospam@example.com (Leo Hsu and Regina Obe) — Fri, 03 Jun 2011 21:42:00 -0400

Since others have shared their PostgreSQL Conference notes on Planet PostgreSQL: Josh Berkus, Blake Crosby, Selena Deckelman, Dmitri Fontaine, Bruce Momjian, Gabrielle Roth, Andreas Scherbaum, and Greg Smith, I thought I'd do my civic duty and add Paul Ramsey's notes to the mix. His are on his corporate OpenGeo blog which is carried by Planet Geospatial and Planet OSGeo but not by Planet PostgreSQL. One thing I admire about Paul is how easily he lets himself be changed by his environment. Sometimes you have to be a little careful what you say to him since he sometimes takes your comments a little too much to heart and changes a little bit more than you had intended. Anyrate here are his notes: PgCon Notes #1, PgCon Notes #2, PgCon Notes #3.