THEOS, An Asset for Cartographers and Planning Managers

THEOS, An Asset for Cartographers and Planning Managers

SHARE

Dr. Darasri
Vice-director
GISTDA,
Thailand
Email: [email protected]

Patrick Houdry
THEOS Pilot Projects Manager
ASTRIUM / Infoterra
Email: [email protected]

To manage country planning, to support economical development along with preservation of environmental assets, to prevent damages due to natural disasters are very challenging issues faced by governments and which require to provide public and private sectors with updated cartographic information. Satellite imagery is a very valuable source of data to undertake production of cartographic maps at different scales. Considering the 1:25.000 scale which is the most adapted scale for organisations willing to work with high scale maps over large areas (complete coverage of large territories can be produced at a reasonable price and in a reasonable time period), a new generation of spaceborne sensors provides the high quality images required for, among which the near-future Thai Earth Observation Satellite (THEOS).Few months ago, GISTDA, Royal Thai Survey Dept. and EADS ASTRIUM agreed to start a collaborative work through the implementation of the THEOS Cartographic Pilot Project. The main objective is to demonstrate the potential of VHR satellite imagery such as SPOT 5 and in the near future THEOS to perform cartography and mapping at a scale of 1:25.000 over Thailand and more generally over Asian countries. A second objective is to anticipate the future delivery of THEOS-based cartographic maps in supplying GISTDA & RTSD with necessary tools and adapted training programs, so that production of cartographic maps will be operational when THEOS will be so.Concretely the THEOS cartographic pilot project is structured as follows:
– Basic data for the production of the 1:25.000 topographic map are 2.5m resolution colour SPOT images (SPOT receiving station hosted in GISTDA).
The first phase (successfully achieved) focused on the production of an ortho-mosaic composed of several SPOT images. A second phase (ongoing, end in September 2006) focuses on the production of a topographic map from the ortho-mosaic. The production process relies on a set of tools developed by French companies, world leaders in the production of geographic information, namely ASTRIUM, Infoterra France, IGN and SPOT-Image:
The ortho-mosaic has been produced by Infoterra France, with its cartographic tool Pixel Factory™. The Pixel Factory™ embeds innovative and state-of-the-art image processing tools ranging from ortho-rectification to mosaicking and colour balancing, allowing a very high level of automation along with an unrivalled quality of the final data. In particular, the geometric correction of the whole mosaic is based on spatio-triangulation techniques, ensuring a very high geometric accuracy. Pixel Factory has been installed in GISTDA, and is now operated by GISTDA cartographic experts.
 Ground Control Points and Digital Elevation Model have been provided by the Royal Thai Survey Department, the Thai Cartographic Institute. Production of the 1:25000 topographic map is under responsibility of SPOT Image and IGN (French geographic institute). The 1:25 000 map features will be collected on the Spot 5 2.5m natural colour ortho-images. The contour lines will be generated from the DTED 2 DEM provided by the RTSD.The proposed conference will focus on:
(i) the outcomes of the cartographic pilot project, i.e. technical outcomes (products, tools) and organisational outcomes (how to get organised to undertake mass production of high quality maps),
(ii) the future perspectives in Thailand and in the region with THEOS