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The maintenance of irrigation infrastructure is the most important demand placed on these systems. However, existing facilities were insufficient, so complete data sources to assist officials in daily tasks and decision-making were established to improve the deployment of water resources and field productivity.â©
The governmental body in the Philippines in charge of supervising water-usage for agriculture is the National Irrigation Authority (NIA). This started a comprehensive nationwide upgrade to irrigation systems in 2010. In addition to renewing and upgrading irrigation equipment such as pumps and reservoirs, NIA also wanted to improve its data management, organise farmers, apportion water, assess performance and bill for irrigation fees â all within the confines of its limited budgets. However, the existing land parcel data was mostly distorted and full of errors, making management hard and the deployment of irrigation less than smooth. Therefore, the NIA instigated a project, âUpgrading of the Parcellary Maps of Selected National Irrigation Systems (NISs)â, to upgrade and integrate NIS information with a GIS. The project targeted 10 irrigation systems covering the most important planting areas in Philippines. Those selected were also intended to be models of modern Philippines agriculture in the use geospatial technologies, as the government is also trying to improve data management in other fields.â©
Building the channelsâ©
The maps were required to contain the following information in different layers.â©
⢠Farm lots/land holdingsâ©
⢠Land use/land coverâ©
⢠Roads and bridgesâ©
⢠Bodies of water, including river, streams and irrigation canalsâ©
⢠Post-processed very high resolution satellite imageryâ©
A local professional geomatics and surveying firm, RASA Surveying, provided a subsidiary of the NIA, NIA Consultant Inc with pan-sharpened, ortho-ready satellite imagery of the targeted areas. The imagery was referenced to the WGS 84 coordinate system and Universal Transverse Mercator (UTM) projection, and had a resolution ranging from 50cm to 60cm. â©
NIA Consultant Inc then imported the imagery into SuperGIS Desktop, and processed radiometric and geometric corrections, producing vector parcel maps in editable SHP and GEO formats, so that officials in others sectors could use the rectified images and data as well. â©
In actionâ©
The built-in COGO (coordinate geometry) tool offers mappers to compile features with accurate lengths and angles. As surveying work can be interrupted by bad weather or budget limits and high-accuracy GPS devices are unavailable, COGO can assist mappers by setting a reference point to process the survey and finish the mapping.â©
As the parcel map is two-dimensional, users can use the Ground to Grid Conversion function in COGO to improve the accuracy of the map and minimise the differences between it and the real world.â©
New workflowsâ©
For farmers, irrigation can be improved and deployed faster, which means the previously sluggish irrigation systems now can respond to the changeable weather and supply water in time, and farmers can take care of their corps with adequate water.â©
The socio-economic influence of the project has been deep and wide: the government gets its deserved income â and the farmers turn their fields gold.â©
Patty Chen is regional manager of Supergeo Technologies (www.supergeo.com.tw)
