REMOTE SENSING REMOTE SENSING SUB- DIRECTORATE

Remote Sensing is... The science of obtaining information about an object by acquiring data with a device which is not in direct contact with that object.

Main Activities: 1. Planning of aerial photography 2. Line Mapping 3. Orthophoto mapping 4. Editing and Archiving 5. Engineering calculations 6. Enhancement of Satellite Imagery 7. Training

1. Aerial Photography Planning: A typical flight plan showing layout of photo strips and photo centres to correct scale The desired position of field control is also shown

FLIGHT PLANS 1. Photography flown without GPS (Full Control) 2. Photography flown without GPS - Strip Surveys 3. Photography flown with GPS In all cases: Planning of flight on 1/ topo map Determine flying height Determine scale of photography

1. Flight plan with GPS Minimum of 8 control points in a block High accuracy required

2. Flight Plan without GPS - Strip Surveys Every second model on outside strips Every third - fourth model on inner strips

3. Flight Plan - Site Surveys Full Control High accuracy

2.Line Mapping: We have one analytical and three analogue stereoplotters We also have a point transfer device used for marking diapositives

A typical model of mapping:

3. Orthophoto mapping: From scanned aerial photography From digital satellite imagery From other remotely sensed data: videography, laser,etc.

Virtuozo System

Orthophoto Map

4.Final Line Map For Archiving

5. Engineering calculations: Areas and volumes for area capacity tables Profile data and maps for backwater calculations and floodline determination Basic design of dumps and storage dams,e.g.. Indumeni Mine

3D View of Indumeni Mine Dump after remodelling:

Remodelling the Indumeni Mine Dump:

6. Enhancements of Satellite Imagery Remote sensing - focus on satellite imagery Change detection Disaster Management Feature highlighting

FIELD CHECKS 1. 50% of area should be tested. 2. Maps with reasonable amount of detail to be selected to check. 3. At least two sections on a map. 4. Tests of all control points. 5. Comparison of detail and plans. 6. Final Reports

SCALES and ACCURACIES SCALES 1. Choice of scale depends on use and accuracy required. 2. Suitable scale is selected in consultation with client. ACCURACIES Standards for Fixing of Control Points

7. Training: Training of Survey Officers to SAQA accreditation Additional survey and photogrammetric training for Technikon students In-house training on stereoplotters and digital systems

Typical categories of work: For design: reconnaissance and planning of infrastructure development As-built - terrestrial monitoring Disaster management: Merriespruit, Rovic Mines Forestry Environmental - coal mines

Continued… For abstraction control: to assist in the compulsory licensing process and to monitor irrigation extents Social consulting - local community involvement (esp. orthophotos) Recreational - dam zoning Calculations for backwater curves and floodline analysis Training - to pass on skills

Key Customers: Directorate: Project Planning Directorate: Civil Design Directorate: Commercial Forestry Directorate: Water Quality Studies Directorate: Internal Projects Directorate: Resources Planning Regions: Water Utilisation Working for Water

Continued….. Social Consultants Other Sub-Directorates in Business Information

The End