A.7    
 

Overview of villages

   
 

During the 2005 National Population and Housing Census, village locations were recorded for the first time using GPS devices. This spatial referencing of statistics at the village level was an important precondition for the development of the present socio-economic atlas, which aims at representing tabular socio-economic data at the highest possible resolution. Two main challenges had to be addressed to generate choropleth maps at a village level for the Lao PDR: The first map relates to the village locations while the second is concerned with the question of boundary delineation in order to be able to depict the village characteristics in an atlas through the use of different colours.

During the 2005 Census the National Statistical Centre (DOS) of the Lao PDR collected data on 10,547 villages throughout the country. However, more and more villages are being re-located, be for spontaneous reasons, or be it as a result of government policies or new development opportunities. In light of these rapid changes it proved difficult to verify the quality of the village data set recorded. So the DOS village locations were compared to the only other national village data set namely that provided by the National Geographic Department (NGD). The comparison with these older data allowed the assessment of those regions of high correspondence where the reliability of the data is expected to be very good, as well as those regions where strong divergence was observed and where the data must be handled more carefully. In total, 1,918 of all villages recorded in 2005 were not recorded by the older NGD maps while on the other hand 2,112 villages of the NGD data set no longer appear in the DOS data. Using additional high-resolution satellite images it was concluded that the newer data set is in general more accurate In 2008, the village data sets of DOS and NGD were harmonised and
a new set of village locations will be released soon.

The second important challenge relates to the definition of the spatial area of each village, as no official village boundaries exist in digital form for the Lao PDR. An approximation of village boundaries by taking half of the physical (Euclidean) distance between two village points proved to be very unsatisfactory. As villages in a very mountainous relief may be close to each other on the map but be very far away in terms of travel time it was decided that travel time would be a better measure. By using the accessibility model presented in Maps A.5 and A.6, lines indicating half the travel time between any two villages were calculated. This allowed defining the so-called village polygons that represent catchments in terms of travel time to the nearest village. The verification with some sample villages for which boundaries were available showed that these approximations were astonishingly precise.

In summary this map depicting the village polygons represents the spatial units on which this atlas presents indicators of the Population Census. It will allow the observation for the first time of the socio-economic disparities and their detailed spatial patterns at a sub-district scale. Given the issues related to village locations which have already been described and the fact that the village polygons are not political or administrative boundaries but rather approximations based on travel time, this atlas is by no means intended to be used as a planning tool at the level of single villages.

 

 

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