Hobu, Inc.

Trac is the best thing since sliced bread. Er, ok, maybe not *that* great, but if there’s any software product out there that embodies that gross word called synergy, Trac is it. It brings the source, bugs, and documentation (wiki) together into a lean, mean, software production machine (again, more hyperbole, but damn I like Trac).

GDAL previously existed on infrastructure spread across at least three different servers. We had CVS hosted at MapTools, Bugzilla hosted at remotesensing.org, and documentation hosted on Frank’s personal server. Having things spread around so much meant that once it was working, it was pretty much left alone, which was ok until stuff broke (thanks MySQL). Our project’s infrastructure made it very difficult for non-developer types to participate other than through maillist interaction.

In January, after approval from the project steering committee, we migrated from our CVS server to Subversion at http://svn.osgeo.org/gdal. This first step allowed us to easily move stuff around in our repository and has given us tons of flexibility. Last weekend, I migrated our Bugzilla to Trac at http://trac.osgeo.org/gdal. The final step of our infrastructure migration gave us stuff we’ve always wanted like a wiki, usable milestones and development roadmaps, and a great source code browser. I’m excited and hopeful that Trac will help the GDAL project scale as it continues to attract more contributors, code, and bug reports

BTW, a member of the ANSI C committee once told me that the only thing rand is used for in C code is to decide whether to pick up the axe or throw the dwarf, and if that’s true I guess “the typical libc rand” is adequate for all but the most fanatic of gamers . _{Tim Peters. 21 June 1997}

import ogr
import osr
import random

ds = ogr.Open(r'c:\hobu\shapefiles\data.shp', 1)

layer = ds.GetLayer(0)
count = layer.GetFeatureCount()
for i in range(count):
    feature = layer.GetFeature(i)
    fudge = random.randint(0,10000)
    geometry = feature.GetGeometryRef()
    gcount = geometry.GetGeometryCount()

    for j in range(gcount):
        g = geometry.GetGeometryRef(j)
        pcount = g.GetPointCount()

        for p in range(pcount):
            x,y = g.GetX(p), g.GetY(p)
            g.SetPoint(p,x+fudge,y+fudge,0)

    layer.SetFeature(feature)

ds.Destroy()

The last two months have also been all-ArcSDE, all-the-time for me, as I’ve worked on three development efforts that have focused on integrating the ESRI database abstraction technology with Open Source technologies.

PySDE

In 2002-2003, I developed a SWIG’ified wrapper to the ESRI ArcSDE C API called PySDE that wrapped up the library and allowed its use via Python. I’ll be the first to admit that it was ugly as hell, but its development was my first introduction to the Open Source GIS community, and although there were some good ideas in it, to be truly useful and sustainable the thing needed to be rewritten.

I’ve been noticing more and more posts on the ArcSDE forums about folks wanting to script and program the ArcSDE SDK with C# rather than going through ArcObjects. I suppose they’re wanting to do this for more control and performance reasons. My experience with both MapServer and GDAL and their SWIG bindings has been very instructive, and I have started rewriting PySDE to follow GDAL’s approach and layout. This means that there is good potential to support more than just Python. I think that PySDE could still fill a useful niche for folks, and I’m looking for folks who wish to support its further development. Head to http://sde.hobu.biz if you’re interested in finding out more and looking at the current state of the code.

GDAL ArcSDE Driver

Project number two related to ArcSDE was the big one — development of a full GDAL raster driver. I had posted a little bit about this last fall, and I was able to secure some funding to make it happen. GDAL now has a driver checked into subversion that supports overviews, statistics, many different data types (1, 4, 8 bit and so on), coordinate systems, and colormaps. Head to http://www.gdal.org/frmt_sde.html to find out more information about the driver. If you’re interested in testing it out (I have been looking for more testers…), grab a copy of FWTools 1.2.2, check the box for the ArcSDE plugin, and after installing, head to http://hobu.stat.iastate.edu/mapserver/build_output/gdal_SDE.zip to get a new version of the plugin that has seen a number of improvements since the FWTools release. You’ll need the ArcSDE 9.1 SDK on your PATH to be able to use it.

Development of this driver was an excellent learning experience, and I would like to thank Frank Warmerdam for his guidance while I developed. I hope that the ArcSDE raster driver proves to be very useful, especially for government types hoping to wedge Open Source GIS’s foot in the door in their machine rooms. I think it (along with MapServer’s SDE support and OGR’s SDE vector support) has the potential to be a major glob of glue for organizations not looking to abandon their editing and analysis tools while still looking to things like MapServer and MapGuide to fulfill their web story.

MapServer ArcSDE Joins

The final ArcSDE item I worked on was small, but not so straightfoward. I added the ability for MapServer’s ArcSDE driver to one-to-one joins with another in-database table. Obviously this is very specific and only useful to a very small percentage of the userbase. One area where spatial databases like PostGIS and Oracle (and maybe MySQL if it ever supported geometric algebra and OGC Simple Features operations) is the construction of a query defines what the “layer” is as far as MapServer is concerned. ArcSDE doesn’t have that luxury, and some fire-burning hoop-jumping is required even to do a simple join.

Hobu Pro

With the upcoming move to the new city, I will also be making Hobu, Inc. a full-time endeavor. It will be an exciting and challenging step to take, but I think that now is as good as time as ever to try and build it into a sustainable business. The timeframe for going full-time is still in the air a bit, as we’ve not yet closed on our house in the old city, but once we know the house is sold (buy it here!), I will give my notice at Iowa State University and head off across the state to do GIS software development and consulting full-time. The hope is that we’re moved to the new city by the middle of April, but real estate markets as they are, it’s hard to know for sure.

I’m excited to bring it full-time, and your chance to hire Hobu Pro ™ to do your proprietary <-> open source GIS software bridging development dirty work is soon approaching