DTM establishment around DTM establishment around Nausori Airport.Nausori Airport.

Siu Pouvalu, s11043110GS 350 Projects in Geospatial Science

University of the South Pacific, SOPAC & Airports Fiji Limited.

IntroductionIntroductionA Digital Terrain Model is a powerful way to

model features on the earth’s surface.

This project provides a 3D visualization of the terrain and potential obstacles within the extent of the Nausori Airport that may cause any disruptions in the operations of aircrafts in this airspace.

ObjectivesObjectives

For Nausori Airport:

Create a DTM with 10 km radius displaying potential obstacles.

Create a DTM with a 45km radius displaying 3D images of the flight altitude within airspace class D and terrain.

MethodologyMethodology

1. Mosaic1. Mosaic•A mosaic is merging a combination of two or multiple raster images into a single image.

2. Georeferencing2. Georeferencing

•Georeferencing involves aligning geometry on raster images to a geographic coordinate system or a base map e.g. the 2008 Aeronautical chart for Fiji.

3. Creating Shapefiles3. Creating Shapefiles

Shapefiles were created and populating their attribute tables using ArcMap and ArcCatalog, also defining their coordinate systems.

4. Buffer : Distance from ARP4. Buffer : Distance from ARP

Both the DEM and image was buffered to a radius of 10km and 45km from the ARP.

Buffer: Flight altitudeBuffer: Flight altitude

Vertical buffer of altitude, using cut polygon.

The flight altitude for each distance from the ARP was also buffered.

15 NA

5. Clip5. Clip

10KM 45KM

6. Digital Elevation Model6. Digital Elevation Model

•25m resolution Digital Elevation Model.

•The 25m DEM was resampled to 10m using the bilinear interpolation method for a smoother surface when draping the ALOS image over it.•Resampling is the process of altering the cell size of either the ALOS image or the DEM. •Bilinear interpolation determines the new value of a cell based on a weighted distance average of the four nearest input cell centers.

7. Drape/Overlay7. Drape/Overlay

Draping the image and the creation of the 3D model was created in ArcScene, extruding features by 5 to show height and altitude.

RESULTSRESULTS

1.) 10 km radius:

Varying altitude at 4 Nautical mile within 10km radius.

Runway 28

Runway 10

10 km radius10 km radiusObstacles on the western side of the airport are higher than that on the eastern side.

Runway 10 is subject to interference from the obstacles and so flight altitude will always be higher on Runway 10 when aircrafts are descending into the Runway for landing or for take-off.

There are 84 villages and 12 settlements within this extent, if any accident shall occur caused by aircraft activity, these areas are subject to compensation.

2.) 45km radius 2.) 45km radius At 25 NA, aircrafts entering the CTR (Control Zone Boundary) and all flight activities are controlled by ATC. At 25 NA aircrafts are to descend to an altitude of 9,500ft from any direction.

Aircrafts may descend or take-off at different altitudes with different bearings at 15 NA. At 2760 an aircraft would descend 4000ft in correspondence with the terrain.

45km radius45km radius

12 NA

7 NA

4 NA

Different flight altitudes is determined by the nature of the terrain. Regulation 98 states aircrafts must operate 1,000 ft above highest terrain and flying over open water must operate at an altitude where if there is engine failure can carry out safe landing.

45km radius45km radius

179 villages

173 settlements

At a 45 km radius, there are 179 villages and 173 settlements within this extent. Any accident or hazard caused by any aircraft operation may affect the natural and human environment within these areas.

ConclusionConclusion

Terrain, wind, obstacles and open water determine the flight altitude of aircraft to avoid any hazards to congested areas, the natural environments and the passengers on board the aircraft. Within a controlled airspace, ATC controls ground and air clearance for each aircraft to avoid any accidents.

This information is useful for:Identifying areas that are at risk of any

accidents due to potential obstacles.A DTM represents features that are

present in an area within a specific time, so this information provides what obstacles are at a specific location and its height. If it is removed, a DTM can show the changes that occur.

Help determine air traffic routing and navigation for the purpose of collision avoidance systems and approximation of ground proximity.

VINAKA VAKALEVU!VINAKA VAKALEVU!