Talks by Julius Sempio
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Thesis Chapters by Julius Sempio
For agriculture to withstand the adverse effects of climate change and remain productive in spite... more For agriculture to withstand the adverse effects of climate change and remain productive in spite of unusual weather phenomena, active adaptation is a practicable option for farmers and government agencies alike. Other strategies, such as the construction of water retention ponds and developing climate-adaptable varieties, require heavy funding that, without institutional support, are beyond the Filipino farmers’ financial capabilities. Also, these strategies take many years to build and bear fruit. In view of these shortcomings and vulnerability to extreme weather events, immediate and low-cost adaptation measures are needed for farmers to consider while waiting for the long-term solutions.
This paper presents the development of a methodology using remote sensing and GIS techniques in determining the vulnerability to climate irregularities of a farming community in Pitpitan, Bulakan, Bulacan. This methodology is intended to become part of a GIS-based climate adaptation recommender system that, in consideration of farmers’ customary practices, will help to inform them of alternative adaptive measures in cases of imminent climate issues such as drought and floods.
Search of related literature, personal visits to concerned local government units, and discussions with Pitpitan’s farmers reveal that, in general, farmers are more concerned with drought than with heavy flooding. Thus focus was given on helping farmers cope with drought conditions, and the developed methodology made use of a reduced version of the agricultural drought vulnerability index (ADVI), which is a data-intensive climatic vulnerability assessment index developed in India. ADVI is modified in order to take into account current data shortcomings of the Philippines, and still come up with a potentially useful analysis tool for extreme climate vulnerability of farm parcels in Pitpitan. The resulting thematic maps are then validated by farmers for being accurate and informative.
A prototype table of recommendations was also developed with the reduced ADVI (rADVI) methodology, which aims to provide farmers with suggested adaptation measures based on their parcels’ rADVI ranking and the expected rainfall situation in the Pitpitan area. These recommendations at parcel level were arrived at using GIS that incorporates both established agricultural strategies and local farmers’ knowledge of time-tested strategies.
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For agriculture to withstand the adverse effects of climate change and remain productive in spite... more For agriculture to withstand the adverse effects of climate change and remain productive in spite of unusual weather phenomena, active adaptation is a practicable option for farmers and government agencies alike. Other strategies, such as the construction of water retention ponds and developing climate-adaptable varieties, require heavy funding that, without institutional support, are beyond the Filipino farmers’ financial capabilities. Also, these strategies take many years to build and bear fruit. In view of these shortcomings and vulnerability to extreme weather events, immediate and low-cost adaptation measures are needed for farmers to consider while waiting for the long-term solutions. This paper presents the development of a methodology using remote sensing and GIS techniques in determining the vulnerability to climate irregularities of a farming community in Pitpitan, Bulakan, Bulacan. This methodology is intended to become part of a GIS-based climate adaptation recommender system that, in consideration of farmers’ customary practices, will help to inform them of alternative adaptive measures in cases of imminent climate issues such as drought and floods. Search of related literature, personal visits to concerned local government units, and discussions with Pitpitan’s farmers reveal that, in general, farmers are more concerned with drought than with heavy flooding. Thus focus was given on helping farmers cope with drought conditions, and the developed methodology made use of a reduced version of the agricultural drought vulnerability index (ADVI), which is a data-intensive climatic vulnerability assessment index developed in India. ADVI is modified in order to take into account current data shortcomings of the Philippines, and still come up with a potentially useful analysis tool for extreme climate vulnerability of farm parcels in Pitpitan. The resulting thematic maps are then validated by farmers for being accurate and informative. A prototype table of recommendations was also developed with the reduced ADVI (rADVI) methodology, which aims to provide farmers with suggested adaptation measures based on their parcels’ rADVI ranking and the expected rainfall situation in the Pitpitan area. These recommendations at parcel level were arrived at using GIS that incorporates both established agricultural strategies and local farmers’ knowledge of time-tested strategies.
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Conference Presentations by Julius Sempio
IEEE Asia-Pacific Conference on Geoscience, Electronics and Remote Sensing Technology (AGERS) , 2023
Cacao (Theobroma cacao L.) is widely cultivated in the cacao belt-l0 to 20 degrees north and sout... more Cacao (Theobroma cacao L.) is widely cultivated in the cacao belt-l0 to 20 degrees north and south of the equator-where the Philippines is situated. Nonetheless, the country suffers from low cacao yield and imports cacao products. The country's cacao roadmap for 2017–2022 identified environmental stress factors such as light intensity, relative humidity, temperature, rainfall, soil quality, flooding, shade, and insect pests and diseases. Conventionally, cacao farmers apply the ground survey method in detecting stress factors, which is prone to human error. This study assessed a cacao farm's stress level through its top environmental stress factors by applying an advanced monitoring system. A combination of the hierarchical modeling in AHP and the GIS method is applied on a specific five-hectare cacao farm to manage the decreasing cacao production. The area boundary was extracted through drone mapping and using an AHP pairwise matrix for an expert ranking of the identified stress factors. In addition, a Sentinel-2 image was used to calculate the normalized difference vegetation index (NDVI) to classify identified areas as healthy, stressed, and very stressed. The NDVI map showed that Zone 3 has the highest average stress level among the four zones. The top five stress factors are insect pests and diseases, floods, soil quality, temperature, and rainfall. Policy implications are derived from these results to mitigate the effects of these stress factors.
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MODSIM 2015, 2015
The increasing frequency and intensity of storms that hit the Philippines and the destructive flo... more The increasing frequency and intensity of storms that hit the Philippines and the destructive floods that follow has made the prediction of outflow behaviour for catchment basins during high precipitation events essential in preparing riverside communities to manage disaster scenarios. This paper reports on the development of an agent-based simulation tool for modeling runoff within the Iponan watershed using a Java-based simulation software called AnyLogic. This tool provides a structured, transparent and interactive approach to helping communities understand the relationship between rainfall, flooding and disaster management, The model applies three hydrometeorological techniques for runoff computations namely, Soil Conservation Service-Curve Number (SCS-CN) for rainfall excess, Clark Unit Hydrograph (Clark UH) for direct runoff and Muskingum-Cunge for channel routing. The model outputs are compared with results from the widely-used HEC-HMS model for validation and accuracy assessment purposes.
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PhilGEOS x GeoAdvances 2019 "Geomatics and Data Science: Towards Adaptive Management in a Changing World", 2019
This paper aims to provide a qualitative assessment of different image transformation parameters ... more This paper aims to provide a qualitative assessment of different image transformation parameters as applied on images taken by the spaceborne multispectral imager (SMI) sensor installed in Diwata-1, the Philippines' first Earth observation microsatellite, with the aim of determining the order of transformation that is sufficient for operationalization purposes. Images of the Palawan area were subjected to different image transformations by manual georeferencing using QGIS 3, and cloud masks generated and applied to remove the effects of clouds. The resulting images were then subjected to structural similarity (SSIM) tests using resampled and cloud masked Landsat 8 images of the same area to generate SSIM indices, which are then used as a quantitative means to assess the best performing transformation. The results of this study point to all transformed images having good SSIM ratings with their Landsat 8 counterparts, indicating that features shown in a Diwata-1 SMI image are structurally similar to the same features in a resampled Landsat 8 data. This implies that for Diwata-1 data processing operationalization purposes, higher order transformations, with the necessary effort to implement them, offer little advantage to lower order counterparts.
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Philippine Geomatics Symposium (PhilGEOS) 2013
The area surrounding the Mandulog River in northern Mindanao has been experiencing changes due to... more The area surrounding the Mandulog River in northern Mindanao has been experiencing changes due to both conversion of forestland to agricultural lands and due to infrastructure and community development in the area. This changing landscape, and the possible effects of a changing climate in Mindanao, may have been factors to the destructive flooding suffered by the lowland areas during the rage of tropical storm Washi (" Sendong ") particularly in Iligan City. This article pieces together observations and researches on the general state of the Mandulog River from the past and the present.
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Philippine Geomatics Symposium (PhilGEOS) 2012
The Pasig River Tributaries Survey and Assessment Study (PRTSAS), besides gathering spatial data ... more The Pasig River Tributaries Survey and Assessment Study (PRTSAS), besides gathering spatial data on the status of the Pasig River's tributary system, includes with it a research that aims to develop a functional, usable, stable and easy-to-appreciate Web-based information system with updated, relevant, reliable and readily accessible data. The tool, named the Pasig River Information System for Management (PRISM), is intended to become useful for urban planners, sanitation engineers and ecologists in reviving the river system itself, redeveloping and beautifying its embankments and maintaining its overall cleanliness. A Web-based GIS, unlike their desktop counterparts, is a spatial information system that can be accessed via an Internet browser. The advantage of such a system is that clients do not need to download special GIS software – they only need their favorite Web browsers to access and work around with the information. As such, utilizing a Web GIS for the PRISM module exhibits significant advantages over making use of desktop ones including, but not limited to, ease of access with a computer connected to the Internet, implementation of differing complexities of available features for different authorities and utilization of a free and open source code for program modifications This paper presents the development of the Pasig River Information System for Management (PRISM) Module version 2.0.
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Philippine Geomatics Symposium (PhilGEOS) 2017
This paper proposes a reduced form of the agricultural drought vulnerability index (Murthy, Laxma... more This paper proposes a reduced form of the agricultural drought vulnerability index (Murthy, Laxman, & Sesha Sai, 2015), that is, some of the contributing indicators for the composite indices were set aside due to data restrictions in the Philippine setting, focusing instead on what data were readily available for the study area: a barangay-level farming community in Pitpitan, Bulakan, Bulacan. The vulnerability map produced by rADVI for the community’s irrigated season was then subjected to validation purposes to see if its output was acceptable to the farmers.
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Philippine Geomatics Symposium (PhilGEOS) 2017
This paper discusses the reasons behind integrating a keypoint database system in the automated g... more This paper discusses the reasons behind integrating a keypoint database system in the automated georeferencing program being developed by the Data Processing, Archiving and Distribution (DPAD) project of the PHL-Microsat program, as well as key issues that were encountered on its presently ongoing testing and implementation.
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Papers by Julius Sempio
Social Science Research Network, 2024
Synthetic aperture radar (SAR) images, while cloud- and haze-free, are limited by being almost ex... more Synthetic aperture radar (SAR) images, while cloud- and haze-free, are limited by being almost exclusively single-band data modified only by signal polarizations, thus necessitating creative approaches to extend their usability. This study aims to develop a data processing pipeline using time series Sentinel-1 SAR data and dynamic time warping (DTW) to identify active sugarcane fields in Tarlac province and test this pipeline by replicating the results of a previous study. Preprocessed datasets are first obtained using Google Earth Engine. Next, using Python and official maps from the Philippines’ Sugarcane Regulatory Administration (SRA), mean reference temporal signatures of select sugarcane parcels were generated by averaging all pixel values within the parcels per date of acquisition, and then plotting the resulting reference signatures into a graph. Each pixel in time series is then subjected to DTW analysis via the DTAIDistance module comparing its temporal signature with the reference and obtaining an accumulated distance cost (ADC) metric to determine said pixel’s (dis)similarity with the reference. The ADC metrics of all pixels are then plotted as a map to reveal the location of pixels that closest to being sugarcane. Finally, the resulting map of this study is compared to the produced map by the previous study, observing a high degree of corroboration between the two maps.
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ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, 2019
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The FAST-SIFT corner detector and descriptor extractor combination was used to automatically geor... more The FAST-SIFT corner detector and descriptor extractor combination was used to automatically georeference DIWATA-1 Spaceborne Multispectral Imager images. Features from the Fast Accelerated Segment Test (FAST) algorithm detects corners or keypoints in an image, and these robustly detected keypoints have well-defined positions. Descriptors were computed using Scale-Invariant Feature Transform (SIFT) extractor. FAST-SIFT method effectively SMI same-subscene images detected by the NIR sensor. The method was also tested in stitching NIR images with varying subscene swept by the camera. The slave images were matched to the master image. The keypoints served as the ground control points. Random sample consensus was used to eliminate fall-out matches and ensure accuracy of the feature points from which the transformation parameters were derived. Keypoints are matched based on their descriptor vector. Nearest-neighbor matching is employed based on a metric distance between the descriptors. ...
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Teaching Documents by Julius Sempio
Mendeley Data, 2024
This data catalog contains analysis-ready time-series synthetic aperture radar (SAR) images of fo... more This data catalog contains analysis-ready time-series synthetic aperture radar (SAR) images of four municipalities of Tarlac Province, Luzon Island, Philippines, and are intended for use in studies exploring time-series data processing techniques such as dynamic time warping (DTW). The two sets of images were derived from Google's Earth Engine Data Catalog - Sentinel-1 SAR Ground Range Detected (GRD) and ALOS-2 PALSAR-2 ScanSAR Level 2.2 - and had already undergone the necessary preprocessing, including conversion into the WGS84 coordinate system, before being clipped using shapefiles of the political boundaries of the aforementioned four municipalities (Concepcion, La Paz, Capas, and Tarlac City). The 34 Sentinel-1 images contain three bands - VV, VH, and angle - and the 19 PALSAR-2 images contain six bands - HH, HV, LIN, MSK, HH_dB (the same HH band but converted from DN to dB), and HV_dB (the same HV band but converted from DN to dB), all taken between November 2016 and March 2018.
As these images have been prepared for the purposes of allowing the replication of the results of the paper "A Pipeline for Mapping Active Sugarcane Fields in the Philippines Using Sentinel-1 SAR Images, Python-Based Modules, and Dynamic Time Warping " (http://dx.doi.org/10.2139/ssrn.4908019), this data catalog also contains the shapefiles used in this study, in the WGS84 coordinate system: the approximated rectangular study area of a related research, and a map subset of official sugarcane parcels within that study area as provided by the Philippine Sugar Regulatory Administration (SRA).
The aforementioned paper is made possible by the ASTI-ALaM Project – a directed Research and Development Project funded by the Philippine Council for Industry, Energy, and Emerging Technology Research and Development of the Department of Science and Technology (DOST-PCIEERD) currently being implemented by the Advanced Science and Technology Institute (DOST-ASTI).
The source codes for the DTW-based mapping application used in the paper is provided via GitHub: https://github.com/JuliusSempio/ALaM_SAR_Mapper
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Talks by Julius Sempio
Thesis Chapters by Julius Sempio
This paper presents the development of a methodology using remote sensing and GIS techniques in determining the vulnerability to climate irregularities of a farming community in Pitpitan, Bulakan, Bulacan. This methodology is intended to become part of a GIS-based climate adaptation recommender system that, in consideration of farmers’ customary practices, will help to inform them of alternative adaptive measures in cases of imminent climate issues such as drought and floods.
Search of related literature, personal visits to concerned local government units, and discussions with Pitpitan’s farmers reveal that, in general, farmers are more concerned with drought than with heavy flooding. Thus focus was given on helping farmers cope with drought conditions, and the developed methodology made use of a reduced version of the agricultural drought vulnerability index (ADVI), which is a data-intensive climatic vulnerability assessment index developed in India. ADVI is modified in order to take into account current data shortcomings of the Philippines, and still come up with a potentially useful analysis tool for extreme climate vulnerability of farm parcels in Pitpitan. The resulting thematic maps are then validated by farmers for being accurate and informative.
A prototype table of recommendations was also developed with the reduced ADVI (rADVI) methodology, which aims to provide farmers with suggested adaptation measures based on their parcels’ rADVI ranking and the expected rainfall situation in the Pitpitan area. These recommendations at parcel level were arrived at using GIS that incorporates both established agricultural strategies and local farmers’ knowledge of time-tested strategies.
Conference Presentations by Julius Sempio
Papers by Julius Sempio
Teaching Documents by Julius Sempio
As these images have been prepared for the purposes of allowing the replication of the results of the paper "A Pipeline for Mapping Active Sugarcane Fields in the Philippines Using Sentinel-1 SAR Images, Python-Based Modules, and Dynamic Time Warping " (http://dx.doi.org/10.2139/ssrn.4908019), this data catalog also contains the shapefiles used in this study, in the WGS84 coordinate system: the approximated rectangular study area of a related research, and a map subset of official sugarcane parcels within that study area as provided by the Philippine Sugar Regulatory Administration (SRA).
The aforementioned paper is made possible by the ASTI-ALaM Project – a directed Research and Development Project funded by the Philippine Council for Industry, Energy, and Emerging Technology Research and Development of the Department of Science and Technology (DOST-PCIEERD) currently being implemented by the Advanced Science and Technology Institute (DOST-ASTI).
The source codes for the DTW-based mapping application used in the paper is provided via GitHub: https://github.com/JuliusSempio/ALaM_SAR_Mapper
This paper presents the development of a methodology using remote sensing and GIS techniques in determining the vulnerability to climate irregularities of a farming community in Pitpitan, Bulakan, Bulacan. This methodology is intended to become part of a GIS-based climate adaptation recommender system that, in consideration of farmers’ customary practices, will help to inform them of alternative adaptive measures in cases of imminent climate issues such as drought and floods.
Search of related literature, personal visits to concerned local government units, and discussions with Pitpitan’s farmers reveal that, in general, farmers are more concerned with drought than with heavy flooding. Thus focus was given on helping farmers cope with drought conditions, and the developed methodology made use of a reduced version of the agricultural drought vulnerability index (ADVI), which is a data-intensive climatic vulnerability assessment index developed in India. ADVI is modified in order to take into account current data shortcomings of the Philippines, and still come up with a potentially useful analysis tool for extreme climate vulnerability of farm parcels in Pitpitan. The resulting thematic maps are then validated by farmers for being accurate and informative.
A prototype table of recommendations was also developed with the reduced ADVI (rADVI) methodology, which aims to provide farmers with suggested adaptation measures based on their parcels’ rADVI ranking and the expected rainfall situation in the Pitpitan area. These recommendations at parcel level were arrived at using GIS that incorporates both established agricultural strategies and local farmers’ knowledge of time-tested strategies.
As these images have been prepared for the purposes of allowing the replication of the results of the paper "A Pipeline for Mapping Active Sugarcane Fields in the Philippines Using Sentinel-1 SAR Images, Python-Based Modules, and Dynamic Time Warping " (http://dx.doi.org/10.2139/ssrn.4908019), this data catalog also contains the shapefiles used in this study, in the WGS84 coordinate system: the approximated rectangular study area of a related research, and a map subset of official sugarcane parcels within that study area as provided by the Philippine Sugar Regulatory Administration (SRA).
The aforementioned paper is made possible by the ASTI-ALaM Project – a directed Research and Development Project funded by the Philippine Council for Industry, Energy, and Emerging Technology Research and Development of the Department of Science and Technology (DOST-PCIEERD) currently being implemented by the Advanced Science and Technology Institute (DOST-ASTI).
The source codes for the DTW-based mapping application used in the paper is provided via GitHub: https://github.com/JuliusSempio/ALaM_SAR_Mapper