October 29, 2009:
In the last few weeks, tensions have been rising between Saudi Arabian border guards and Yemeni tribesmen who live along the border. The source of the tension is a fence that the Saudis are building. The problem is that neither country has agreed on exactly where the border is. Moreover, the tribesmen do not want a fence blocking their way, as the border has never been recognized by the tribes that live astride it. The big problem is that Saudi Arabias land borders are mostly sand. The dunes keep moving as the winds blow this way and that. Historically, the local warlords used the few obvious landmarks to establish a vague border. But now there is GPS, and most countries in Arabia are ready to establish precise borders. The problem is that each country has a different idea of where the real border, as precisely marked by GPS, is.
The negotiations proceed, but the tribesmen living astride the border are often not willing to negotiate. In that case, force must be used. But first, both nations involved have to agree to apply force. That is not a problem on the Yemen border, because those Yemeni tribesmen that have been shooting at the Saudi fence builders, are already at war with the Yemeni army. But throughout Arabia, there will be more disputes like this, probably for decades, until all the borders are agreed on.
Other parts of the world, where there are mountains and rivers to serve as unambiguous borders, also have problems if the people (often from the same tribe) living astride the border, refuse to accept international borders (which means dealing with border guards. Even India and China have border disputes, because of conflicting claims about where the real border is.
Border disputes have been a major cause of wars for thousands of years, and even the arrival of inexpensive GPS and electronic mapping systems, is not going to solve all the disputes. GPS just makes the disputes more detailed.