Satellite Exploration of Thailand > Project

Khao Phra Viharn

Image Description
Image 1:
IKONOS (source: Point Asia, acquisition date: 2005-02-08)
Image 2:
IKONOS + SRTM (overlaid at 60% transparency).
yellow line - border demarcation traced from the L 7017
purple line - presumed current border demarcation (approximately)
blue line - stream
red dotted line - footpath traced from the L 7017
white dotted line - Bandai stairway
G1 ... G4 - 1st Gopura ... 4th Gopura


The L 7017 presents one version of the Thai-Cambodian border demarcation at Khao Phra Viharn. This border demarcation line is still widely adopted by various Thai maps such as the S 1501, MapMagic Thailand and the ESRI GPS map. Some curious readings of this line are:
  1. The area in the immediate west of the sanctuary complex belongs to Thailand
  2. Cambodian jurisdiction over the sanctuary complex extends just as far as the First Gopura to the north
  3. The eastern cliff edge of Pha Mo I Daeng (near the national park parking lot) belongs to Cambodia

It is to the understanding of the author that the 1962 ruling of the International Court of Justice was over the jurisdiction of the sanctuary complex itself, and that the actual border demarcation of the area was not an issue. Understandably, the Thai Government grudgingly receded minimal territory to Cambodia to comply with the ICJ ruling, and marked as such on its official map.

The 1962 ICJ ruling jeopardized the rule of watershed divide in the area, though it still basically holds in other border areas between Thailand and Cambodia. Simply put, at Khao Phra Viharn, there's no clear or general rule to demarcate the border boundary. Each territorial clash must be solved by negotiations, but is more often left unsolved, adding to the demilitarized no man's land.

The present situation - and since at least as far back as 1998 when Khao Phra Viharn was reopened to tourists from the Thai side after the Khmer Rouge handed over the sanctuary to the Cambodian Government - is that the narrow plot of land at the foot of the monumental stairway is occupied by Cambodian vendors as a makeshift market, and the small bridge over the often dry creek at the northern edge of the market effectively constitutes the Thai-Cambodian boundary. Effectively, that is. The author is yet to confirm a formal agreement between Thailand and Cambodia on this issue. And it is not known to the author exactly when this small bridge assumed such a role. Perhaps there has been a territory exchange: the stairway and the market area went to Cambodia and Pha Mo I Daeng to Thailand?

This creek, incidentally, flows into Sra Traw reservoir and, via Huai Takhob, ultimately joins the Mun River. The unregulated wastewater from the Cambodian market caused river pollution in Thai villages and, in protest, the Thai Army closed the border gate in 2001, stranding the Cambodian vendors at the market without income or food supply from the Thai side. This move, ironically, gave a push to the Cambodian Government to start on its aspiring project - a direct access road to Khao Phra Viharn from the Cambodian side. The road was pushed through vehemently, and was opened for vehicle passage in 2003. Thailand lost its honorable position of providing the only practical entrance to Khao Phra Viharn.

This new road clearly passes through the L 7017-defined Thai territory, but the Thai Government responded with a curious silence. Is it to be taken as a tacit approval by the Thai Government that the territory the new road runs through belongs to Cambodia? Or has there been a covert deal among the parties involved?

Listed below are two editions of the S 1501. Map 1 is the original US compilation and Map 2 is a revised Thai edition. Notice the conspicuous discrepancy in border demarcation at Khao Phra Viharn. The boundary line of Map 1 probably corresponds to the so-called Annex I map which is often mentioned in name in historical discussions but hardly ever reproduced in material for reference. The boundary line of Map 2 is congruous to the L 7017.

Map 1 (Date of information: 1973)

Map 2 (Date of information: 1985)

Chong Ta Thao

While the new access road to Khao Phra Viharn was pushed through, another road was being engineered in its eastern vicinity to connect to Chong Ta Thao.

Chong Ta Thao, as the SRTM image indicates, forms a natural pass and, as such, it probably historically served cross-border trade and migration in the region. The Landsat image from as early as 1973 shows what appears to be a dirt track connecting Thailand and Cambodia through this pass. Presumably, Chong Ta Thao has been providing cross-border vehicle passage on limited occasions and purposes.

With the new road connected to Chong Ta Thao, Cambodia requested Thailand to "upgrade" the pass to a permanent (international) border crossing to boost regional tourism. Also in its tourism promotion plan were a casino resort and a cable car to access Khao Phra Viharn from the eastern side. The Thai Army and local Thai villagers, however, expressed opposition to Cambodia's proposal - the former citing the danger of residual landmines and the latter in fear of adverse effects on their youths of attracting gamblers. At the time of writing, I have yet to read a news report that Chong Ta Thao has been opened either for permanent (international) or temporary (local) border crossing.

1. The top IKONOS image shows the north-south axis of the sanctuary to be 88.48o whereas the actual axis based on GPS survey is 89.48o. Thus by rotating the image by 1.00o counterclockwise, the image would match the GPS track around the sanctuary. However, the author found this operation to cause utter mismatch on the western end of the image, meaning, probably, the IKONOS image is intrinsically deformed and difficult to rectify over an expanded area with high precision.

2. Point Asia's high-resolution IKONOS image is interrupted at the Khao Phra Viharn National Park parking lot, and re-emerges some 20km to the east. The interrupted border area, according to the Landsat image, is largely deforested on both sides of the boundary, and traces of dirt tracks appeal to one's imagination that some irregular activities are taking place.

3. The author hasn't had a chance to read the full text of the 1962 ICJ ruling. The Khao Phra Viharn National Park pamphlet notes the essence of the ICJ ruling as (parentheses by the author),
  1. To return the area of 150 Rai ( = 0.24km2)
  2. To return of 150 ruins (removed artifacts?)
  3. To withdraw police and soldier from the area
Incidentally, the territory excluded in the L 7017 approximately amounts to 0.24km2.

4. The road data of Map 1 probably dates back a further few years before 1973. The 1973 Landsat image shows completion of the basic highway network in the area - R 221 to the present-day National Park parking lot (and a little beyond), R 2248 branching off to the east and R 2235 to the west.

5. Map 1 shows a curious "cart track" (according to its legend) from Ban Don Ao to Khao Phra Viharn where it connects to the downhill footpath to Cambodia. The 1973 Landsat image shows a trace suggestive of this track - as well as several other traces stretching toward Khao Phra Viharn. The author deems it plausible that this track - now disused and overgrown - once provided vehicle access to Khao Phra Viharn before the completion of R 221 from the eastern side.

6. A former Khmer Rouge soldier is reported as saying that, prior to the 1998 surrender of the sanctuary to the Cambodian Government, a dry-season 4WD track was already in use to access Khao Phra Viharn from the Cambodian side. (Phnom Penh Post, link).

7. The author hasn't had a chance to inspect the newly published L 7018 yet. Perhaps its border demarcation line is more up-to-date.

8. See also my former compilation Khao Phra Viharn

Available upon request:
1. Original stitch of the top IKONOS image (3540 x 4600 px, 6.08MB, jpg format)
2. Borders on the Fantastic: Mimesis, Violence, and Landscape at the Temple of Preah Vihear, 1998, P. CUASAY - a curious legal/historical review on the 1962 ICJ ruling