Geoinformatics & IT

EO, IT, GIS, IoT, ...

Mapping roads in Mekong Delta, Vietnam

Calculation of a “remoteness index” for selected households

Introduction

The three objectives of this project are to experiment with digitizing from satellite imagery, to experiment with the creation and modification of network transport models and to be able to compute measures related to remoteness for selected households in the area, with the help of GIS network analysis methods. The area of interest is the Mekong Delta, Vietnam. A survey was conducted where 638 households in the area were identified, in search of “pockets of poverty”. Both the locations of each household and a number of points marking the route taken to reach them were documented using GPS. Thus, the requirement for this exercise is to build (rather, extend the existing) network to connect the survey points and to measure the remoteness of each one of them.

Data

The data for this project consists of the following:

NameDescription
network_baseExisting road network (not very precise)
survey_pointsLocation of survey points and group number of each point
gps_tracks_pointsInterviewers track-logs (points) with speed data
gps_tracks_linesInterviewers track-logs (lines)
mekong_urban_largeCentroid points for large urban areas (incl. Ho Chi Minh)
mekong_urban_midCentroid points for mid-size urban areas (communes with a population density >1000 people/km2)
mekong_communesPopulation data (polygons)

Methods

The given network included only major roads, most of which could not “reach” the survey points. The first step for this exercise was to extend the road network. In ArcMap, a World Imagery layer was loaded behind the other layers. The World Imagery layer provide Earth Observation imagery in a concise way, similar to the way Google Earth does. In combination with the interviewers’ track-logs (points), the base road network was digitized and connected to the not-very-precise existing road network. While digitizing, each network line segment was given a default speed ID value, according to the table:

IDDescriptionDefault speed (km/h)
12path20