Tuesday, December 11, 2012

Debugging maptiler on Mac

Running maptiler on Mac is no easy task, as I've found out.

While there are a few stumbling blocks when it comes to dependencies, one that I found particularly perplexing is the bundling of a two Python executables in the .app package.  The maptiler executable is written in such a way as to not only to run the rest of the package through one or other of the Python executables, but to choose based on 32 or 64 bit architecture.  That's independent of the version of Mac OS being run, or the "current" Python.  Most dependency installers will install relative to the "current" Python, and its path.  Therefore, on the 32-bit MacBook Pro I was testing on, I was being kicked on to the bundled Python 2.5 executable, and missing all my dependencies.  This caused various dependency errors, including "ImportError: No module named osgeo"

Here is are the important diffs in maptiler.app that caused it to work: in ../MapTiler.app/Contents/MacOS/maptiler 6,9c6,9 < #if sys.maxint > 2**32: < executable = os.path.join(execdir, "PythonSnow") < #else: < # executable = os.path.join(execdir, "Python") --- > if sys.maxint > 2**32: > executable = os.path.join(execdir, "PythonSnow") > else: > executable = os.path.join(execdir, "Python") and in ../MapTiler.app/Contents/Resources/maptiler/pp/__init__.py 141,147d140 < # fix PYTHONEXECUTABLE dict error < < if "PYTHONEXECUTABLE" in os.environ: < executable = os.environ["PYTHONEXECUTABLE"] < else: < executable = sys.executable < 156c149 < command = "\"" + executable + "\" -u \"" \ --- > command = "\"" + os.environ["PYTHONEXECUTABLE"] + "\" -u \"" \
Relevant link at Google Code: http://code.google.com/p/maptiler/issues/detail?id=42

Friday, December 7, 2012

My Places Overlays on Maptiler Google Map

Maptiler is a good option for creating image overlays (such as historical maps) on Google Maps.  There are some snags though -- the code is still using gmaps API v2, which will give some indication for the attention being given to the project right now.  

 The problem I ran into was adding overlays (such as a KML or GeoRSS feed) on TOP of the image overlay, and correct behavior with the opacity slider built into the maptiler output.

Here are the simple edits to fix this issue.

  1. Added a My Places KML overlay by copying the KML URL from My Places and these two lines (I put those at 185, just below the construction of the new map object)
  2.  geoXml = new GGeoXml("https://maps.google.com/maps/ms?authuser=0&vps=1&ie=UTF8&msa=0&output=kml&msid=204904299571298064529.0004d01c986fdc0fe9f19");  
  3. Changed zPriority of maptiler overlay so that it sits below other overlays (I edited the line at ~224 which constructs the "overlay" object
      overlay = new GTileLayerOverlay( tilelayer,{zPriority:-1000});  
  4. Finally, I fix the opacity slider by changing the line that removes all overlays to just remove the maptiler overlay, and reinitilize it at zPriority -1000 around line 62
     this.map.addOverlay(this.overlay, { zPriority: -1000 });  
    That's it!

Hit the geocoding wall?

Google's Geocoding API limits results to 2,500/day.  So what are your options when you hit a geocoding wall with a public/free API?
  1. Using ArcGIS (or alternatively Gisgraphy, which I have not yet experimented wtih http://www.gisgraphy.com/) you can geocode against the best data you can get your hands on.  Esri Streetmaps Data is great, if you have access (as we do at UD).  Or you could download public data, like the Census TIGER data, geonames, or an openstreetmap extract for the area you're interested in, and geocode on these. There is some high quality dataset from cities and states.  In the case of Delaware,  which licenses TeleAtlas (now TomTom) data, I don't think non-state users are permitted to use it.  I have not seen a way to do this in open source GIS software (e.g., QGIS), which is why ArcGIS or Gisgraphy would be required
  2. Mapquest/Nomatim (http://developer.mapquest.com/web/products/open/nominatim) and  Cloudmade  have an unlimited geocoding APIs on OpenStreetMap data.  Sometimes that can be slow or inaccurate though.
  3. Mapquest (non-Nomatim) and Yahoo also have a 5000 result/day limit ... a 2x improvement on Google