[数据求助] CEPII数据库下载的城市距离数据表里的指标都是什么意思 [推广有奖]

1.iso2, iso3, cnum: ISO codes in two and three characters, and in three numbers respectively.
2.country, pays: Name of country in English and French respectively
3.area: Country’s area in km2
4.dis_int: Internal distance of country i, dii = .67parea/π (an often used measure of
average distance between producers and consumers in a country）
5. landlocked: Dummy variable set equal to 1 for landlocked countries.
6.continent: Continent to which the country is belonging
7. langoff_i: Official or national languages and languages spoken by at least 20% of the
population of the country
8. lang20_i: Languages (mother tongue, lingua francas or second languages) spoken by at
least 20% of the population of the country.
9.lang9_i: Languages (mother tongue, lingua francas or second languages) spoken by between 9% and 20% of the population of the country. 6.
10. colonizeri: Colonizers of the country for a relatively long period of time and with a
substantial participation in the governance of the colonized country.
• short_colonizeri: Colonizers of the country for a relatively short period of time or
with only low involvement in the governance of the colonized country
• city_en, city_fr: Names of capitals or main cities of the country in English and
French.
• lat, lon: Latitude and longitude of the city.9
• cap: Variable equals to 1 if the city is the capital of the country, to 0 if the city is the most
populated city (maincity equals to 1) but not the capital, and to 2 in the cases of two
capitals, if the city is the most populated but the “second” capital or the previous capital10.
• maincity: Variable coded as 1 when the city is the most populated of the country and as
2 otherwise11.
• citynum: Number of cities for each country used to calculate our weighted distances described in the next section.