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GIS/RS Developments

1. Digital Terrain Models for Low Lying Islands

Digital Terrain Models are raster data sets providing for every grid cell the height. They are required to:

  • Monitor beach movements of low level islands;
  • Simulate flooding of low level areas and
  • Rectify image data using ortho rectification methods.

Required are DTMs of sub-metre contour lines (20-30cm) at 1:10,000 scale.

Developments

One method to generate the DTMs was tested under real conditions in Marshall Islands.

Deployment of RTK GPS. SOPAC has purchased equipment, which can be utilised for this purpose in all Pacific Island Countries.

Outstanding Problems/ Issues

The problems are:

  • The survey is very time consuming;
  • High level of training is required to operate the system and
  • The image analysis software distributed in Pacific Island Countries: ERDAS does not allow an efficient DTM editing such as break lines.

2. GIS for Pacific Utility Applications

The main users of GIS in the Pacific are the utilities. For more than 10 years now GIS has been customised for utility needs.Ready-made softwares are now available in Europe and North America and serve the needs. Due to relatively small amount of customers and other specific condition, big solutions failed in the Pacific.

Developments

GIS is more sustainable if it established by the staff of the utility itself. Since half a decade SOPAC has strongly pushed to separate spatial and tabular data. This has been accomplished in several utilities in the Pacific. The next step is to integrate modelling into the GIS Application and to move to more capable database software allowing database replication.

Outstanding Problem/Issuesng

There are also efforts in trying to intergrate load flow analysis and GIS using MapBasic and Access Basic to automate Mapinfo with Ms-Access? as fronts-ends and MySQL in the back-end. Visual Basic can be used to automate ArcGIS.

3. Radar Application for Fishing Vessel Detection

The Vessel Monitoring System (VMS) has been running for many years now in Honiara, Solomon Islands at the Forum Fisheries Agency (FFA). Fishing vessels will have to take on-board transmitters, which sends signals to a satellite, which is than sent to FFA. This will then enable FFA to know the position of the vessel that is displayed on a GIS.
To cross check VMS space borne radar data could be ideal as they can be recorded in all weather conditions. The old generation of radar satellites such as ERS1, ERS2, RadarSat-1, ENVISAT, etc. recorded with an inappropriate spatial resolution. The new generation of radar satellites have a spatial resolution of 3 to 1 metre sufficient to even see the shape of the vessel.

Developments

Projects set up 3 years ago between Fiji, FFA and SOPAC to check the VMS with radar data. The radar recording had to be ordered 6 weeks in advance and an area was selected where fishing vessels are normally concentrated at the particular time of the year. However, during the recording time most fishing vessels were outside the selected area and the project was a failure. Today the recording can be made some days in advance and the data can be downloaded 12 hours after recording. This would be a totally different situation, however, a new test has to be started. The idea is to cross check the VMS with samples of radar recording and compare the number of recorded ships in the VMS and number visible in the radar image. In addition, is possible to record the speed of the vessels and it might be possible to detect if the boat is made out of steel, wood or fibre glass, which narrows down if it is a recreation, transport or a fishing vessel.

Outstanding Problem/Issues

The technique has to be checked and customised but is generally available. A request from SOPAC’s member countries is necessary to start to test the application.

4. Radar Application for Mapping Extent of Flooding and Coastal Change

TerraSAR-X’s satellite radar technology is particularly applicable for flood event mapping as it is weather-independent and offers fast revisit times to track the scale of a floods rise and fall. For insurance firms it provides extremely accurate flood footprints to help in the estimation of the spatial height and extent of flood damage. Infoterra’s radar images will also support insurance companies in flood modelling and scenario generation, based on the analysis of estimated maximum losses from historic flood data.

Developments

Radar application for mapping of flooded areas was tested in Nadi area, which is flat, and high-resolution image data was available to re-rectify the radar data. If we want to apply high-resolution radar technology in more professional way for rapid flood access or rapid mapping of coastal erosion in other Pacific Island Countries we need: a) Software in the range of USD 25,000, b) DTMs at 1:10,000 scale for the corresponding islands and c) hardware facilities to process radar data before the analysis is sent to the island. So far, we do not have radar data processing facilities in the Pacific.

Outstanding Problems/ Issues

We have two problems a) the responsiveness of disaster management organisations and b) lack of data acquisition. Disaster management organisations prioritise the building of houses and roads. We need to get proper data for the disaster management organisations in order to be able to create the maps needed for disaster management.

5. Vegetation Mapping

A vegetation map is attributed with site based data where individual sites have been grouped based on structural characteristics and presence/absence of species. The groupings of sites are referred to as vegetation communities and are used to describe the map units defined on the interpretive base..

Developments

a) Kiribati has received training in digitising, editing of digitising, geometric correction and subsequent GIS backdrop production, change detection and basics of image enhancement. Vegetation stratification is going ahead we have received the first MapInfo files.

b) Vegetation maps at 1:12,500 scale for Tuvalu and Kiribati produced between 1972 and 1980 were found. These maps will be scanned which then allow change detection between the vegetation cover now and before.

c) Tonga has expressed interest to get assistance to do their vegetation mapping; we are in correspondence.

d) GTZ (German aid) has expressed interest to get involved in vegetation mapping.

e) An attache at SOPAC has been tasked to investigate the stratification potential for bread fruit and pandanas.

Outstanding Problems/ Issues

Vegetation mapping with satellite images need adaptation when applied under Pacific conditions for example:

  • Textural separation between coconut and other vegetation types requires exact interpretation keys;
  • Local haze influences the interpretation;
  • In volcanic islands with higher mountains (Fiji, Solomon Islands or Samoa) the lee side of mountains require special spectral correction and
  • Some secondary pioneer species can indicate high vegetation although having thin canopy mostly over hang slides.

6. DTM Editing

DTMs are necessary for especially for especially low lying islands and flood plains as explained above. DTMs have to be edited to:

  • make brake lines visible
  • edit obviously wrong height data for example created through multiple GPS receiving
  • cut and shape into map coverage, etc

Developments

Currently the only software distributed in the Pacific Island Countries is ERDAS where the spatial modeller is capable to handle part of the mentioned tasks.

Outstanding Problems/ Issues

An appropriate software is required to allow GIS&RS users in the Pacific Island Countries to edit DTMs. Investigations are on the way to user surfer software for this task.

7. Utilisation of Google Earth Image Display

Google Earth is available and can be utilised for many applications where other image data is currently not affordable

Developments

Sharing utilities layers as .kml/.kmz  for viewing in google earth

Outstanding Problems/ Issues

It has to be investigated how acceptable the geometric accuracy is when related to the mapping scale of the utilised application.

8. Semi Automatic Map Content Capture

GIS Users in Pacific Island Countries received substantial amount of training to produce and utilise GIS backdrops instead of digitising tables. SOPAC offers for member countries to scan available maps and convert to GIS backdrops. It would be an essential step ahead if it would be possible to clarify the map content semi automatically and create a database of area analysis.

Developments

The procedure worked relatively well through a maximum likelihood image classification for a map of Christmas Islands, Kiribati where the water was recognized and separated from other map content. This was performed with low resolution scanning which has the disadvantage of high amount of mixed pixels can be dropped by increasing the resolution, however color is then recognized as texture and so far texture recognition is not included in the available image analysis software.

Outstanding Problems/ Issues

The GIS&RS service unit tested the semi-automatic recognition of Geology classes of scanned maps based on ESRI software. ArcScan is an extension to ArcGIS Desktop that provides a comprehensive and easy-to-use set of tools for raster-to-vector conversion. Unfortunately, ArcScanitself cannot be used to get a final shape file; it has to be combined with manual digitizing tools.So far the results are not promising, however, further test with are ongoing hoping to create more positive results.

9. Open Source Software Application

The use of Free and Open Source(FOSS) for GIS applications in the region is inevitable. It is clear that most GIS users cannot afford proprietary software. Consequently, many GIS applications remain underutilized because most organizations owns only a single license and therefore the application is not readily available on multiple locations. All this can be changed by the use of FOSS for GIS Software tools since they are more powerful and usable for developing systems where more and more public participation is required. In this regard the proposed discussion will help us understand the potential and limitations of FOSS for GIS in the region.

Developments

The Pacific Hydrological Cycle Observing System (HYCOS) is using Quantum GIS (QGIS) with PostGIS/PostgreSQL (Postgres) to integrate with its Time Dependent Data (TIDEDA) database and Microsoft Access attributes.

Usage of PostGIS/PostgreSQL, QGIS, QGIS Server, QGIS Cloud for Utilities GIS/RS Applications.

Outstanding Problems/ Issues

Have to rewrite MapBasic code in Python to be added as add-ins in QGIS.

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