A Blending Technique of Topograhic and Hydrographic DEMs for River Alignment Modelling

A Blending Technique of Topograhic and Hydrographic DEMs for River Alignment Modelling

Abstract:

Current practice in combining bathymetry and topographic DEM is based on overlaying and merging both datasets into a new DEM based on river boundary. Throughout a few sample of datasets from previous recent projects, authors realize that this method is not preserving the nature of natural river characteristic, especially at the slope in between riverbank and riverbed. Some arising issues were also highlighted; validity of the topographic DEM as well as the river boundary, limitations of DEMs and how bathymetry survey was carried out on field. To overcome these issues, a new technique called blending DEMs was proposed and tested to the project datasets. It is based on a fusion of two DEMs (with respective buffer, offset and fusion ratio from a validated river boundary) to produce riverbank slope and a merging of two different interpolation results to produce a best riverbed DEM. Simple riverbank ontology was prescribed to illustrate the model enhancement in accuracy and visualization provided by this technique. The output from three projects / DEM results was presented as a comparison study between the current practices with the proposed technique.

 

Article by:

Hairi Karim (I Net Spatial Sdn Bhd), Mohamad Ghazali Hashim and Mohd Radhie Mohd Salleh (I Net Spatial Sdn Bhd)

 

How to cite:

Karim, H., Hashim, M. G., and bin Mohd Salleh, M. R.: A BLENDING TECHNIQUE OF TOPOGRAHIC AND HYDROGRAPHIC DEMs FOR RIVER ALIGNMENT MODELLING, Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci., XLII-4/W5, 113-119, https://doi.org/10.5194/isprs-archives-XLII-4-W5-113-2017, 2017.

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Integrated GIS System in Disseminating Spatial Information for Malaysia Development Approval

Integrated GIS System in Disseminating Spatial Information for Malaysia Development Approval

Abstract:

Every year, World Bank Group (WBG) is conducting assessment for 190 countries and produces a ranking report based on Doing Business performance – an initiative to measure benchmark efficiency on business regulation and their enforcement by a sample study (e.g. for Malaysia is Kuala Lumpur City Hall - DBKL). One of the ranking categories is based on Dealing with Construction Permits (DCP) which made us proud as announce Malaysia ranks for 2019 is #3 (based on 2018 assessment). This achievement was based on continues efforts and studies from the last bottom of #137 (since, 2007), #113 (2012) and continues with positive results (straight improvement) respectively till this year. Maintaining the top three ranks is not an easy task; however, is not impossible either. Lots of study in innovations, suggestions and implementation should be carried out to maintain and improve Malaysian DCP ranks. As per DCP of this year assessment, Work Bank has suggested all countries with 5 new suggestions (new additional marking schema). One of them is to engage Geographic Information System (GIS) for land use, cadastre, water, electricity and sewage related datasets. This paper propose an initial study (concept paper) towards engaging GIS in DCP activity as a response (first action) suggested by World Bank Group; crucial in maintaining DCP rank for 2020 as well as to provide better business regulations and enforcements for DBKL or other local authority. Later, an impact study will be conducted, utilizing new integrated GIS system publishing service (GeoMap) and the output of the study will indicate whether Malaysia Productive Corporation (MPC) should engage or ignore the 5th suggestion by World Bank Group, or to enhance with other initiatives.

 

Article by:

Hairi Karim (I Net Spatial Sdn Bhd), Dato Abdul Latif Abu Seman (Malaysia Productivity Corporation), Mohamad Azrol Mohamad Dali, Siti Zurianah Othman, and Siew Chengxi Bernad (Geotech Solutions Sdn Bhd)

 

How to cite:

Karim, H., Abu Seman, D. A. L., Mohamad Dali, M. A., Othman, S. Z., and Bernad, S. C.: A PROPOSAL TO IMPLEMENT INTEGRATED GIS SYSTEM IN DISSEMINATING SPATIAL INFORMATION FOR MALAYSIA DEVELOPMENT APPROVAL (STAKEHOLDERS AND APPLICANTS) – A CONCEPT PAPER, Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci., XLII-4/W16, 347–358, https://doi.org/10.5194/isprs-archives-XLII-4-W16-347-2019, 2019.

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An Indicator-Based Approach for Micro-Scale Physical Flood Vulnerability Mapping

An Indicator-Based Approach for Micro-Scale Physical Flood Vulnerability Mapping

Abstract:

Map representation of vulnerability is a crucial step in evaluating flood impact and all vulnerability indicators that are the final product of risk assessment. So far, in flood risk assessment, this is probably the weakest link. Flood risk mapping suffers from inequality in the level of development in presenting the different components: where exposure and hazard modelling and mapping is well developed and advanced, while vulnerability analysis and mapping are underdeveloped. Therefore, the objective of this paper is to discuss a newly developed GIS-based approach on micro-scale flood vulnerability mapping of physical elements at risk using an indicator-based method. Micro-scale flood vulnerability is used to eliminate flood vulnerability in an area with a high probability of occurrences. The approach is suitable for cost-benefit analysis of structures protection measures. At micro-scale flood vulnerability mapping, it is more suitable to adopt indicator-based vulnerability assessment methods. Because it provides an opportunity for incorporating all the factors and characteristics of elements at risk that contribute to generating their flood vulnerability. Likewise, a considerable amount of studies argue that vulnerability assessment and its representation on maps should focus on the identification of variables that influence the vulnerability of an element at risk. Flood vulnerability mapping at micro-scale provides critical information for the decision-makers on why specific infrastructures are susceptible more than the others. Moreover, assessing and managing flood risk is crucial in order to reduce the loss and adapt to the combined effects of rapid urbanization and climate changes.

 

Article by:

Ismaila Usman Kaoje, Muhammad Zulkarnain Abdul Rahman*, Tze Huey Tam and Mohd Radhie Mohd Salleh (I Net Spatial Sdn Bhd)

 

How to cite: 

Kaoje, I. U., Abdul Rahman, M. Z., Tam, T. H., and Mohd Salleh, M. R.: AN INDICATOR-BASED APPROACH FOR MICRO-SCALE PHYSICAL FLOOD VULNERABILITY MAPPING, Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci., XLII-4/W16, 331–337, https://doi.org/10.5194/isprs-archives-XLII-4-W16-331-2019, 2019.

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Spatial Prediction Models for Landslide Activity Mapping Using Vegetation Anomalies

Spatial Prediction Models for Landslide Activity Mapping Using Vegetation Anomalies

Abstract:

An area that located in Kundasang which in Ranau district in Sabah, Malaysia that lies along the bank of Kundasang valley was chosen for comparing the reliability of frequency ratio (FR) and weight of evidence (WoE) methods for landslide activity probability mapping by using related vegetation anomalies indicator. The locations of 47 and 189 of active and dormant landslides respectively were identified using 4 raster layers (topographic openness, hillshade, colour composite and high resolution orthophoto). Each landslide activites were randomly divided into two groups as training (70%) and testing (30%) datasets. Tree height irregularities, DVI, NDVI, SAVI, and OSAVI were considered as landslide bio-indicator. The landslide activity probability maps were prepared using the FR and WoE method. The generated maps were validated by calculating the success and prediction rates from area under receiver operating characteristics (ROC) curve. The results of WoE method were relatively reliable (AUC > 0.8) for dormant landslide while only about 40% of active landslide have been predicted accurately. Similar trend yielded for FR method where least accuracy for active landslide prediction.

 

Article by:

Mohd Radhie Mohd Salleh (I Net Spatial Sdn Bhd), Zamri Ismail, Shakirah Amirah Binti Mohd Ariff, Muhammad Zulkarnain Abd Rahman*, Mohd Faisal Abdul Khanan, Mohd Asraff Asmadi, and Khamarrul Azahari Razak 

 

How to cite: 

Mohd Salleh, M. R., Ismail, Z., Mohd Ariff, S. A., Abd Rahman, M. Z., Abdul Khanan, M. F., Asmadi, M. A., and Razak, K. A.: SPATIAL PREDICTION MODELS FOR LANDSLIDE ACTIVITY MAPPING USING VEGETATION ANOMALIES, Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci., XLII-4/W16, 441–449, https://doi.org/10.5194/isprs-archives-XLII-4-W16-441-2019, 2019.

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Multi-Scale and Scale Dimension Properties in Spatial Raster Modelling – Concept and Current Implementation

Multi-Scale and Scale Dimension Properties in Spatial Raster Modelling – Concept and Current Implementation

Abstract:

Various users and applications required different abstraction details of spatial model either in vector or/and raster data types/models. Generating different model abstraction details (e.g. Level of Detail/LOD) produces various drawbacks especially for data model sharing among stakeholders or publics. Different abstraction detail or LOD means different details in geometry, semantic information, attributes as well as different accuracy provided within the vector model (e.g. a certain LOD). On the other hand, raster dataset with different resolutions on certain information or layer (e.g. elevation, land cover, spatial imagery, soil type, thematic raster map and others) could also be considered as multi-scale raster modelling which produces similar drawbacks with additional storage redundancy/consumption and updating works. There are some solutions for vector scale modelling such as CityGML (3D) and multiscale or vario-scale (2D) modelling induce good solutions for vector; however, there are no solution for raster data type (or model) yet. Thus, a concept description in categorizing and defining multi-scale for multi-resolution raster dataset should be introduced. This paper basically highlights the similarity of spatial 2D vector and raster type GIS dataset, some introduction and properties of raster dataset which able to be defined it as the same level of vector LoD in scale modelling. This paper basically tries to kick off a new multi-scale domain in supporting spatial raster dataset (new idea), which will be then be extend/expand by related researchers near the future. Discussion on successful implementation of vector multi-scale model will be in the paper as well as existing multiscale approach in storing raster dataset as the main content of the paper. Some potential analysis on related multi-scale raster and validation are also discussed to give brief idea on what is spatial raster capable of; especially to those who are new/not yet engage with this multi-scale spatial raster dataset.

 

Article by:

Hairi Karim (I Net Spatial Sdn Bhd), Alias Abdul Rahman, and Mohd Radhie Mohd Salleh (I Net Spatial Sdn Bhd)

 

How to cite: 

Karim, H., Abdul Rahman, A., and Mohd Salleh, M. R.: MULTI-SCALE AND SCALE DIMENSION PROPERTIES IN SPATIAL RASTER MODELLING – CONCEPT AND CURRENT IMPLEMENTATION, Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci., XLII-4/W16, 339–345, https://doi.org/10.5194/isprs-archives-XLII-4-W16-339-2019, 2019.

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