Free Shapefiles of Countries of the World (2)

Note: read also part 3 and part 4 of this blog.

After input on my recent blog (thanks!) and after that I find two more, another post about this.

To judge the quality of the dataset, I use my own country (the Netherlands) as the primary measure. I've a mental map about my country, and know how it should look like. In many of the found datasets it looks completely destroyed. Therefore, personally I would discard them at once. Other datasets quite precisely depict my country. Maybe it is not only because I live here, but also about the topography: it has a large inner lake, it has some islands, and it has a distinctive shape.

So here the previous datasets, and four more, and some variations, come again...

	(1) from aprs file world.shp from 2002 244 countries Missing a polder existing since 1968
	(2) from brothersoft, serving blue marble data file World_countries_shp.shp from 1996 239 countries All shape is destroyed
	(3) from Geodan file WorldCountries.shp from 2003 253 countries The Netherlands are depicted correctly
	(4) from mapping hacks file world_borders.shp from 2004 251 countries, 3784 polygons Showing a polder which is never realized
	(5) from thematic mapping file TM_WORLD_BORDERS-0.3.shp from 2008 246 countries Showing a polder which is never realized
	(5b) also from thematic mapping but the simplified version file TM_WORLD_BORDERS_SIMPL-0.3.shp also from 2008 also 246 countries Badly simplified
	(6) from openmap here, called cntry02 file cntry02.shp from 2002 251 countries Showing a polder which is never realized, missing three islands
	(7) from this site ESRI data file cntry08.shp from 2008 249 countries Missing three (inhabited) islands in the North. For the rest it looks like a good map on this scale
	(8) from vdstech via this blog file world.shp from 2001 251 countries Badly simplified
	(9) from natural earth file 10m-admin-0-countries.shp  from 2009 251 countries Missing the inner lake the IJsselmeer
	(9b) from natural earth file 50m_admin_0_countries.shp  from 2010 240 countries Missing the inner lake the IJsselmeer
	(9c) from natural earth file 110m_admin_0_countries.shp  from 2010 177 countries Too much simplified
	(10). I wanted to do VMAP0 / VMAP1 here. However, my little research concerns a (one) shapefile of countries of the world. Vmap0 is great but to let users figure out all the detailed files and merge them for four parts of the world is not the purpose I started the research with... so no picture here. Thanks for the tip anyway.
	(11) from huebler file world_adm0.shp  from 2002 209 countries Missing the inner lake the IJsselmeer

Based on this series, (3) would probably be the best choice, though a bit heavily detailed. Surprisingly, it is created in the Netherlands... So we cannot judge its quality from this series. Furthermore,  (7) would be a reasonable choice, but we saw in the previous blog that (7) is wrong with respect to the Caspian sea. The new dataset (9b) is looking quite good to me for a map on world scale, but alas it misses an important lake. We might see more in another blog, for example showing the countries around the Caspian sea, or the countries in the former republic of Yugoslavia.


Conclusion

I think a good and free shapefile of the world is still welcome.

Free Shapefile of Countries of the World

Note: read also part 2 and part 3 of this blog.

I'm always surprised that it is hard to find a good shapefile with world countries. I need country vector data for Boost.Geometry sample data. There is some there but I want to have another set. I want to have it as WKT (Well-Known Text) and I can use a shapefile as input.

Asking Google for "free world map shapefile" you get:

• aprs (1), with also a modified version
• blue marble requires registration, but (probably) the same set can be downloaded from the next entry
• brothersoft, serving blue marble data (2)
• mapcruzin (leading to no countries but several interesting other shapefiles)

Via my company, Geodan, you can also download a worldmap, here (requiring mailing your contact information) (3)

Via free gis data, here, there is a hit on ESRI, leading to this site, leading to annual subscriptions etc.. I skipped this one.

Via similar terms ("countries") we also find:

• mapping hacks, serving three world files (4)
• actually originating from this site, which has a more actual version (5)
• a file from openmap here, called cntry02 (6)
• and finally (via "cntry08") we find ESRI data here (7)

I've downloaded these shapefiles. It gives me (file dates):

1. is from 2002, modified in 2009 for Antarctica
2. is from 1996
3. is from 2003
4. is from 2004
5. is from 2008
6. is from 2002
7. is from 2008

The Netherlands
Let's first show my country, the Netherlands:


All borders through each other look quite messy... But let's concentrate on the data.
Southern Flevoland, a polder, already existing since 1968, is still not there on maps from 1 (aprsworld, green) and 2 (blue marble, so blue). Of course it is present on the map of my company 3 (geodan, red), because Geodan of course takes care for its own country. Southern Flevoland is also present on all newer maps (5, pink, 6 orange, 7 gray). But on 5 and 6 it has a planned but not realized polder (Markerwaard) included. So best for the Netherlands are 3 and 7.

Of the five inhabited islands along the Waddenzee, 7 depicts only two. So here 3 is the best choice (of course, it is our country, and note that for the rest this is not a commercial talk)

For the whole world, 6 and 7 are quite similar in nearly all aspects

Uruguay
Let's now look at a country not part of Europe or US. I select Uruguay:


The blue vectors are quite rough and shifted to the west and north. Green lines are looking nice for a map on this scale, but deviate a bit from all other maps.

Let's now take a look in Google Earth. For this, we need to create a KML file...  hmm, shp2kml cannot be downloaded (blank website saying Missing ID). OK, we use PostGIS then, it can create KML and WKT (we need it below).

shp2pgsql -s4326 world.shp world1 > world1.sql
etc

So I created a database called blog and executed these SQL files.
Five minutes later (PostGIS is great) I do:
psql "-F " -A -n -t -q -Upostgres -dblog "-cselect '<Placemark>',ST_AsKml(the_geom),'</Placemark>' from world2 where name='Uruguay'" -otworld2.kml
 
Doing this for all tables and reworking the KML's  a bit (adding headers etc) gives me:


Considering Google Maps as our Single Point of Truth, we can discard the blue lines from Blue Marble, and might think that the green lines are also wrong. The rest is following the borders more or less but we need to zoom in to judge it better.

This is the new detail on a border:


The Yellow line is Google's line. The red line is following it, probably a bit too much. For a global scale, the other ones (4,5,6,7) are doing well here.

Caspian Sea
Looking at global level, we see immediately one thing, on which we zoom in here: it is surprising that the Caspian sea is not included in map 6 and 7. So the country borders are just across the sea... Not so good.


Not so good. So let's discard 6 and 7. We also see that the red lines (3) are too detailed, also here. Discard 3. Blue (2) and green (1) was already discarded before. So we keep 4 and 5, which are roughly the same. So I decide to keep the more actualy one: 5.

Decision
So we conclude, based on a few samples (and some more but not described here), that the file TM_WORLD_BORDERS-0.3.zip  from Thematic Mapping is the best shapefile to use for worldscale countries (even though it contains the Markerwaard).

Country number and validity
We did not consider attributes, and our research was still rough.

An important aspect we want to consider is geometric validity. And, even more important, the number of countries, it can differ over years, but the differences are sometimes still surprising.

Dataset	Invalid (SQL Server)	Invalid (PostGIS)	#Countries	Year
1	1	1	244	2002 / 2009
2	4	3	239	1996
3	34	5	253	2003
4	5	6 polygons	251 (3784 polygons (this dataset contains polygonsp; not multi-polygons)	2004
5	5	4	246	2008
6	3	0	251	2002
7	2	7	249	2008

About the countries themselves, I just glanced through the differences using a query, comparing ISO3 country codes, getting this table:


We see some inconsistent and some missing ISO codes, and some countries not in the one but in the other, and vice versa.


Conclusion

I think a good and free shapefile of the world is still  welcome.