Taiwan Today

The National Land Use Monitoring Program uses satellite imagery to prevent environmental destruction caused by illegal development.

In October 2007, 's FORMOSAT-2 satellite made a routine pass high above 's Luodong Forest District, snapping images of the area and downloading them to 's (NCU) Center for Space and Remote Sensing Research (CSRSR) in Jhongli, . There, a high-tech system began processing the images and comparing them to shots of the same location taken in July 2007. After the system finished digesting the new data, it suddenly issued a warning--something had changed on the ground in the forest at Luodong.

Poring over the images, CSRSR operators diagnosed the change as a new, privately constructed building where none had been before. The operators reported the change to Luodong management and the Comprehensive Planning Department in the Construction and Planning Agency of the Ministry of the Interior (CPAMI), a Cabinet-level government agency in charge of managing, regulating and developing the nation's land. The forest district ordered a field investigation of the area in question and discovered a newly built shed for rearing and housing chickens.

A records check showed that the new building had been erected without permission. Luodong staffers immediately reported the results of their investigation to CSRSR and CPAMI, with the central government agency passing on the finding to local authorities. They in turn asked the building owner to remove the structure. The whole process took less than three months from the time the change was first detected by the system to the time the building was dismantled.

The use of satellites to monitor land resources began when the launched Landsat 1972 to track grain production. CSRSR began operating in 1984 with the mission of teaching and researching remote sensing related sciences, technology and applications. In its early days, CSRSR obtained images from satellites such as 's SPOT 1. Since 1993, CPAMI has been obtaining images from the research center and cooperating with it to monitor surface changes in . The nation's first observation satellite, FORMOSAT-1, was launched in 1999 and the National Land Use Monitoring Program (NLUMP), a project aimed at detecting surface changes in , was initiated in 2001.

At CSRSR, satellite imagery is used for a multitude of tasks, but the research center's work with CPAMI focuses on ferreting out unauthorized land use. Aside from protecting the natural environment in areas such as Luodong Forest District, the program also plays an important safety role--when buildings are constructed without the proper permits, they most often do not adhere to construction codes, and are thus dangerous to those that use them. Moreover, they cannot legally connect to municipal and rural water and sanitation systems, so unauthorized buildings also negatively affect the environment and nearby residents.

The launch of the monitoring program and the use of the satellites, which CSRSR employees enthusiastically refer to as "the eye of heaven," has helped to fight the misconception held by some businesses and individuals that there is nothing to hinder building upon or otherwise developing unoccupied, apparently unclaimed land. Before 2001, efforts to detect illegal land use in were spotty and mostly depended on public reporting of suspicious construction to authorities, says Ju Ching-luen, section chief of CPAMI's Comprehensive Planning Department. "Aerial photography was sometimes used to monitor land use, but its cost was high and it usually just covered a small area," Ju explains. "That's why, before the new system, local government agencies mostly depended on the public and routine patrols to report illegal activities."

Radical Change

This traditional way of monitoring the nation's land use relied heavily on manpower and was neither comprehensive nor efficient. Its effectiveness was often affected by various human factors including how much attention the public paid to changes on nearby land, how eager people were to report those cases and how much pressure local legislatures brought to bear on local government agencies. The launch of NLUMP radically changed the nation's watch on land use from a bottom-up dynamic--residents reporting changes to local governments, which then may or may not have reported changes to the central government--to one that starts at the top, with a Cabinet-level agency leading the way. The reliable data collected by satellites has also made it almost impossible for local government agencies to find any excuse for neglecting cases of illegal land use. According to Ju, local governments have completed investigations of 90 percent of land change cases after receiving notification from the monitoring program. Since 2001, the system has detected more than 1,250 suspicious land change cases, with more than 15 percent proving to be illegal.

Some 30 staffers work at the CSRSR building at NCU, where they monitor images from FORMOSAT-2 during its daily passes over . Images captured by 's SPOT 5 satellite are also received and stored as part of the data collection. The system is able to record images of each of the nation's approximately 36,000 square kilometers every day.

Once the images are received, they are selected and integrated, with those containing clouds and shadows eliminated in favor of clear ones to provide a complete view of the nation's land. The system then runs an automatic cross-checking process comparing the newly acquired photos to archived images to detect possible land use changes. Areas tentatively identified as showing changes are then examined by the system's operators to eliminate changes resulting from seasonal agricultural use or vegetation changes.

Up until March this year, the integration and cross-checking process was performed twice annually. However, as land use can change very rapidly, with some rough constructions erected in around a week, Ju says the integration and checking process is now being performed each month.

After the screening, images that show changes in land use are then processed through a Web-based geographical information system (GIS) to identify the area's map coordinates and government administrative districts. After the location is specified, CSRSR operators report suspicious changes to CPAMI and local government agencies and request an on-site survey. The results of the site survey by local government agencies, with pictures taken at the location, must be sent back to CSRSR within three weeks. The Web-based GIS data is available to local governments and field investigators, allowing them to download coordinates, maps and satellite images to portable personal digital assistants (PDA) and global positioning systems (GPS), making the task of locating a specific area easier and more accurate.

Chen Chi-farn, an NCU associate professor and CSRSR's lead investigator for the NLUMP project, is proud of the system. "Very few countries are able to accomplish 100 percent monitoring of their land as has accomplished with this project," Chen says. "Though many other countries may have the ability to apply satellite image technology in various fields, it's still rare to find such a comprehensive system backed up with a complete administrative network."

Big Challenges

Nevertheless, the current smooth and orderly operation has not been arrived at without a great deal of work. Chen and CPAMI's Ju both agree that the project's biggest challenge came from convincing local governments to adopt the new detection system and integrate it into their daily work routine. Chen recalls the resistance he encountered from many local government workers due to their lack of technical skills. "[In the beginning,] many of them didn't know how to use the Internet and computers very well, let alone the GIS and digital field investigation system we offered," he says.

It took CSRSR several years to train local government workers through seminars and individual step-by-step instruction over the phone. Chen and his team have also worked hard to make the system's Web interface more user friendly for local government users. To make the process run more smoothly, Ju says that CPAMI has devoted part of its project funding to subsidize local government purchases of PDA and GPS devices for use in site surveys. CPAMI also rewards local government agencies that conduct quick and comprehensive field investigations.

While NLUMP relies heavily on high-tech tools, it also recruits volunteers--mostly members of environmental organizations and elementary and middle school teachers--to monitor the nation's land use the old-fashioned way: by checking out sites on foot. The volunteers use a special Web-based system that gives them access to digital maps and coordinates. Once their fieldwork is completed, they report back to CSRSR. Training sessions are held to give volunteers instruction on basic geographic concepts and the system's Web applications. In other words, while the bulk of the NLUMP's data comes from CSRSR, the system is also able to accommodate information sourced from the field. After volunteers send in their reports, CSRSR adds their observations to the CSRSR database and cross-checks them against satellite images of the location. The volunteer network, Chen says, also allows them to track the progress of the cases they have reported.

Finding Funding

Though the operation and technology of the NLUMP system have matured, Ju from CPAMI and Chen from CSRSR both point out the need to secure more stable funding. NLUMP's funding is allocated through CPAMI, and the planning agency's budget must be reviewed and approved by the Legislative Yuan each year. If the full budget is not approved, CPAMI must look for areas to save money, and, despite its success, NLUMP is often one of the first programs to see its funding reduced. Instead of the annual budget scramble, Ju and Chen would like for NLUMP to be able to raise funds on its own. Ju brings up the example of the National Concert Hall on the grounds of the National Taiwan Democracy Memorial Hall in as an example. Just as the concert hall is able to cover some of its expenses by selling tickets to shows, he believes CSRSR should be able to charge fees for the images and services it provides, which would give the program a more stable source of funding. He points out that the system provides valuable data to many levels of government. This data could be used by government planners to track development around high speed rail stations, allow the Council of Agriculture to monitor fallow farmland and enable the Environmental Protection Administration to detect pollution in rivers.

CPAMI researcher Wang Li-ling also emphasizes the need for passing and enacting legislation such as the proposed National Land Use Planning Act and the National Land Remediation Rules. First proposed in 1995, the National Land Use Planning Act would provide a comprehensive, long-term planning platform. The proposed legislation stipulates that a land monitoring system must be used, and thus would require a stable budget for the system. Ju believes that the act has languished for so long because the legislature places a low priority on planning issues.

The National Land Remediation Rules were proposed in 2005 to provide a legal foundation for protecting coastlines and rivers, as well as restoring areas where land has subsided or been damaged by development. The proposed rules also call for the use of a monitoring mechanism such as NLUMP. However, they have yet to be voted on by the legislature.

Resolving Resolution

Yangmingshan National Park (YNP) technical specialist Jacky Chang has served as the park's NLUMP coordinator for the past five years. He believes the system has played an integral role in raising public awareness about the nation's land use, but thinks NLUMP is limited by the resolution of the satellite images it generates. The current resolution can show the general shape of objects or plots of land as small as four square meters. However, this resolution cannot clearly show details of smaller structures or plots that might be used for agricultural cultivation. And even though NLUMP now updates and cross-checks its database on a monthly basis, Chang still finds it more effective to rely on the park's personnel resources to uncover changes in land use. "Right now we've got eight patrol officers and together they can cover the whole area of the park every day," Chang says. He believes that the foot patrols are much faster than waiting a full month for the NLUMP system to show cases of illegal cultivation in the park. That is also why the unusual land activities detected by the monitoring system only account for a small portion of all the cases  found in Yangmingshan, Chang says.

Besides using NLUMP to detect land changes, CPAMI has also been exploring other applications for the system. The most successful example has been a program monitoring 's coastline. Launched in 2005, the CPAMI coastline program won a National Sustainable Development Award in 2006. "Only a very limited proportion--44 percent--of 's coastline is in natural condition," Ju says. "It's important to watch for any changes to prevent the existing natural coastal environment from being damaged." Although many changes to the coastline result from the government's development plans, Ju explains, data collected by NLUMP serves as a reference for the authorities. For example, if a satellite image shows that very few fishing boats are berthed at a fishing port, the local government may reconsider the need to build a new jetty.

As for the future, Ju hopes that NLUMP will be more widely publicized so that people will think twice before building on unused land without first obtaining legal permission. Nevertheless, through working with the program, he says he has gradually gained a sense of greater responsibility to protect the land. "Illegal buildings are usually poorly constructed and likely to bring about pollution of the land and water," he says. "In the end, it's all of us who have to bear those effects. All of us have to realize that the land belongs to the public, and we must have the courage to act when any illegal land uses are found."

Write to Audrey Wang at awang@mail.gio.gov.tw