Semi‐automated methods for mapping wetlands using Landsat ETM+ and SRTM data

Islam, Md. Ashraful; Thenkabail, Prasad S.; Kulawardhana, R. W.; Alankara, R.; Gunasinghe, Sarath; Edussriya, C.; Gunawardana, A.D.S.

doi:10.1080/01431160802235878

Cited by 46 publications

(35 citation statements)

References 18 publications

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“…Other related methods for swidden agriculture discrimination also include supervised/unsupervised classification, decision tree classifier, image enhancement involving band ratios, and object-based image analysis. Take the image enhancement technique for example; multispectral satellites (e.g., Landsat) provide various band ratios to display enhanced images in red, green, blue or false color composite and highlight the land cover differences [122,123].…”

Section: Spectral Signatures Based Approachesmentioning

confidence: 99%

A Review of Swidden Agriculture in Southeast Asia

et al. 2014

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Swidden agriculture is by far the dominant land use system in the mountainous regions of Southeast Asia (SEA). It provides various valuable subsistence products to local farmers, mostly the poor ethnic minority groups. Controversially, it is also closely connected with a number of environmental issues. With the strengthening regional economic cooperation in SEA, swidden agriculture has experienced drastic transformations into other diverse market-oriented land use types since the 1990s. However, there is very limited information on the basic geographical and demographic data of swidden agriculture and the socio-economic and biophysical effects of the transformations. International programs, such as the Reducing Emissions from Deforestation and forest Degradation (REDD), underscore the importance of monitoring and evaluating swidden agriculture and its transition to reduce carbon emission due to deforestation and forest degradation. In this context, along with the accessibility of Landsat historical imagery, remote sensing based techniques will offer an effective way to detect and monitor the locations and extent of swidden agriculture. Many approaches for investigating fire occurrence and burned area can be introduced for swidden agriculture mapping due to the common feature of fire relatedness. In this review paper, four broad approaches involving spectral signatures, phenological characteristics, statistical theory and landscape ecology were summarized for swidden agriculture delineation. Five research priorities about swidden agriculture involving remote sensing techniques, spatial pattern, change, drivers and impacts were proposed accordingly. To our knowledge, a synthesis review on the remote sensing and outlook on swidden agriculture has not been reported yet. This review paper aims to give a comprehensive overview of swidden agriculture studies in the domains of debated definition, trends, remote sensing methods and OPEN ACCESSRemote Sens. 2014, 6 1655 outlook research in SEA undertaken in the past two decades.

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Section: Spectral Signatures Based Approachesmentioning

confidence: 99%

A Review of Swidden Agriculture in Southeast Asia

et al. 2014

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“…Method selection was based on ground-truth assessment of different flood classes. Once the optimal method was selected, our main goal was to implement a semiautomatic procedure to produce systematically reliable and comparable flood maps of the Doñana marshes for the last 40 years [36]. The selected method should be consistent enough to be applied over a radiometrically normalized long time series of Landsat images.…”

Section: Introductionmentioning

confidence: 99%

Long-Term Monitoring of the Flooding Regime and Hydroperiod of Doñana Marshes with Landsat Time Series (1974–2014)

et al. 2016

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This paper presents a semi-automatic procedure to discriminate seasonally flooded areas in the shallow temporary marshes of Doñana National Park (SW Spain) by using a radiommetrically normalized long time series of Landsat MSS, TM, and ETM+ images . Extensive field campaigns for ground truth data retrieval were carried out simultaneous to Landsat overpasses. Ground truth was used as training and testing areas to check the performance of the method. Simple thresholds on TM and ETM band 5 (1.55-1.75 µm) worked significantly better than other empirical modeling techniques and supervised classification methods to delineate flooded areas at Doñana marshes. A classification tree was applied to band 5 reflectance values to classify flooded versus non-flooded pixels for every scene. Inter-scene cross-validation identified the most accurate threshold on band 5 reflectance ( < 0.186) to classify flooded areas (Kappa = 0.65). A joint TM-MSS acquisition was used to find the MSS band 4 (0.8 a 1.1 µm) threshold. The TM flooded area was identical to the results from MSS 4 band threshold < 0.10 despite spectral and spatial resolution differences. Band slicing was retrospectively applied to the complete time series of MSS and TM images. About 391 flood masks were used to reconstruct historical spatial and temporal patterns of Doñana marshes flooding, including hydroperiod. Hydroperiod historical trends were used as a baseline to understand Doñana's flooding regime, test hydrodynamic models, and give an assessment of relevant management and restoration decisions. The historical trends in the hydroperiod of Doñana marshes show two opposite spatial patterns. While the north-western part of the marsh is increasing its hydroperiod, the southwestern part shows a steady decline. Anomalies in each flooding cycle allowed us to assess recent management decisions and monitor their hydrological effects.

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“…The importance of wetlands and their management has gained increasing recognition in many parts of the world (Islam et al, 2008). Thus, a reliable inventory and map of wetland systems is very useful to understand the spatial distribution of different wetlands and their linkage with other land units.…”

Section: Introductionmentioning

confidence: 99%

“…Thus, a reliable inventory and map of wetland systems is very useful to understand the spatial distribution of different wetlands and their linkage with other land units. This will help in planning, management and conservation of wetlands (Islam et al, 2008;Rebelo & Nagabhatla, 2009). Remote sensing offers the opportunity to map and inventory wetlands rapidly and consistently, irrespective of the geographic location (Islam et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

“…This will help in planning, management and conservation of wetlands (Islam et al, 2008;Rebelo & Nagabhatla, 2009). Remote sensing offers the opportunity to map and inventory wetlands rapidly and consistently, irrespective of the geographic location (Islam et al, 2008). The approach covers large areas, and is cost-and time efficient making it for wetland characterization (Xie et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

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Comparison of Spot and Landsat Data in Classifying Wetland Vegetation Types

Mosime

Tesfamichael

2017

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

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ABSTRACT:The aim of this study was to compare the performances of Landsat and SPOT imagery to map wetland vegetation types in the Klipsriviersberg Nature Reserve, South Africa. The Gauteng Conservation Plan 3.3 (C-Plan 3) was used to delineate the boundaries of the wetlands in the study area. According to the plan, the proposed study area falls within the Critical Biodiversity Areas (CBA) and Ecological Support Areas (ESA). Limited field data were collected within the boundaries of the wetlands during summer 2015 when the vegetation cover was relatively high. These data identified features including sparse vegetation, dense vegetation, grassland and bare land.Additional samples were added from Google Earth image to increase sample size. Both the field data and Google Earth data were used as reference against which the performances of SPOT and Landsat product were compared. Unsupervised classification was used to classify SPOT and Landsat images acquired in summer 2015. The results showed that overall accuracy of SPOT images is higher than Landsat images. This is attributed to its high spatial resolution of 1.5 m compared to 30 m spatial resolution of Landsat imagery. This indicates that SPOT imagery is recommended to map wetland vegetation diversity in a localised area such as the study area. The current high temporal resolution of the image has also an added advantage that conservationists should exploit.

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Semi‐automated methods for mapping wetlands using Landsat ETM+ and SRTM data

Cited by 46 publications

References 18 publications

A Review of Swidden Agriculture in Southeast Asia

A Review of Swidden Agriculture in Southeast Asia

Long-Term Monitoring of the Flooding Regime and Hydroperiod of Doñana Marshes with Landsat Time Series (1974–2014)

Comparison of Spot and Landsat Data in Classifying Wetland Vegetation Types

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