Update Sep.21.2011: I took the code in this post and part deux and made a github project off of it called Gborders. The code is simpler and there are more options to generate the borders overlay based on geographic regions. Happy forks!
One thing I needed when designing the Meteoalarm mashup for Spincloud were the political boundaries for all European countries. With them at hand, I would use the polygon overlay from the Coogle API and fill the country polygons with the respective weather warning colors.
This first part is a tutorial on how to import world political borders into a MySQL database table.
The second part in these series will use this table to create a script that will add the country borders overlay to Google Maps.
So after learning that Google Maps API doesn’t give programatic access to the political boundaries I moved on to doing it myself. I read about the encoded polylines and figured that I only missed the country boundaries as encoded polygons so I started searching for readily-available resources. Sure enough there were nowhere to be found.
The next best thing was to find the country boundaries in some GIS format and generate the polyligons myself. The information seems to be sparse but after a bit of research I found was the CIA World Databank but the format is incomplete, it only defines the polygons with no country names or any other administrative hook that I would be able to use. I then spent hours trying to find a better resource until I remembered that Mapping Hacks (an excellent book by the way) has data set for the examples in the book. I had the first breakthrough, the website makes available updated world borders files here, they are mirrored from thematicmapping.org.
We’ll use a utility called shp2mysql to export the boundaries to SQL. I’m on a MacBook and no shp2mysql binaries for my platform were available in the original package so we’ll have to compile it first then run it to be able to export the shapefile to SQL.
Below are detailed all steps needed to to produce the borders SQL file on Leopard 10.5.x (note that you have to have the Developer Tools installed). In short, copy and run the following script on your mac in a file called process_boundaries.sh. The script creates a file called wb_dump.sql which is ready to be imported into database:
mkdir borders cd borders wget http://mappinghacks.com/data/TM_WORLD_BORDERS-0.2.zip mkdir boundaries_shp unzip TM_WORLD_BORDERS-0.2.zip -d boundaries_shp wget http://kartoweb.itc.nl/RIMapper/code/shp2mysql_0_4.zip unzip shp2mysql_0_4.zip -d shp2mysql_04 wget http://dl.maptools.org/dl/shapelib/shapelib_1_2_10.zip unzip shapelib_1_2_10.zip cd shapelib-1.2.10 make cd .. rm ./shp2mysql_04/src/*.o sed 's/^OBJS.*$/OBJS = \.\.\/\.\.\/shapelib-1\.2\.10\/shpopen\.o \.\.\/\.\.\/shapelib-1\.2\.10\/dbfopen\.o/' shp2mysql_04/src/Makefile > shp2mysql_04/src/Makefile2 mv shp2mysql_04/src/Makefile2 shp2mysql_04/src/Makefile cd shp2mysql_04/src make cd ../../ cp shp2mysql_04/src/shp2mysql . ./shp2mysql -d boundaries_shp/TM_WORLD_BORDERS-0.2.shp world_boundaries test_db > wb_dump.sql rm *.zip rm -rf shp2mysql_04 rm -rf shapelib-1.2.10 rm -rf boundaries_shp
Make the above script executable then run it:
chmod +x process_boundaries.sh ./process_boundaries.sh
If you’re interested in the details about this script then read on otherwise happily skip it. The final SQL file is linked at the end of this post.
We’ll start by bringing the shape files:
mkdir borders cd borders wget http://mappinghacks.com/data/TM_WORLD_BORDERS-0.2.zip mkdir boundaries_shp unzip TM_WORLD_BORDERS-0.2.zip -d boundaries_shp
The files are in ESRI’s shp format which wasn’t exactly what I needed. I had to export them in a more usable format, SQL in my case. For this I used the shp2mysql utility for which I didn’t find the MacOS executable so we’ll compile it from source. Since it has a dependency to shapelib we have to download and compile it along:
mkdir shp2mysql wget http://kartoweb.itc.nl/RIMapper/code/shp2mysql_0_4.zip unzip shp2mysql_0_4.zip -d shp2mysql wget http://dl.maptools.org/dl/shapelib/shapelib_1_2_10.zip unzip shapelib_1_2_10.zip cd shapelib-1.2.10 make cd ..
Now you should have both shapelib and shp2mysql downloaded with shapelib succesfully compiled. Now we’ll compile shp2mysql: we have to delete all .o files (they have been compiled for a different platform), fix the Makefile then issue the make command
rm shp2mysql/src/*.o sed 's/^OBJS.*$/OBJS = ../../shapelib-1.2.10/shpopen.o ../../shapelib-1.2.10/dbfopen.o/' shp2mysql/src/Makefile > shp2mysql/src/Makefile2 mv shp2mysql/src/Makefile2 shp2mysql/src/Makefile cd shp2mysql/src make cp shp2mysql/src/shp2mysql .
which should execute successfully.
We’re ready to export the world boundaries into SQL format. Switch to the boundaries folder then issue the export command as follows:
cd .. ./shp2mysql -d boundaries_shp/TM_WORLD_BORDERS-0.2.shp world_boundaries test_db > wb_dump.sql
this will create a SQL file called wb_dump.sql ready to be loaded into your database.
Running the script will generate a file called wb_dump.sql which is ready to be imported on your spatially enabled database:
All we have to do now is to import the sql file into the database. Note that the database has to be spatially enabled (MySQL is by default, I’m using 5.0). Issue the following command:
mysql -uroot -p my_database < wb_dump.sql
Now we should have country borders for the whole world imported in the database.
For convenience, I have made the world boundaries SQL file available for download (4.3 MB).
In the second part of this how-to, we’ll use this table to create the country borders overlay for Google Maps.