Worksheet to Chapter 3 - Teacher Instructions

A Question of Resolution

Objectives:

Spatial resolution is an indication of how a satellite sensor can record spatial details such as lakes, houses, cars or persons. This resolution is essential and must be selected according to the respective application and size of the analysed area. Monitoring weather conditions with satellite images a large area view, but lower spatial resolution is needed. Monitoring urban planning requires very high resolution but only for a smaller area.

Didactical commentary:

• To complete this worksheet, the students should find pros and cons for the use of different spatial resolutions and then choose the right spatial resolutions with respect to the particular applications given in the table.
• In addition, the students are asked to search the Internet to find the primary applications for the satellites Landsat, SPOT and QuickBird.

Solution to the Worksheet 'A Question of resolution':

1. Different resolutions for different applications. a. Complete the table which demonstrates how different resolutions are suitable for different applications. Use the following scale: + (best suited for purpose), o (moderatly suited for purpose), - (poorly suited).

   Applications	Low resolution	Medium to high resolution	Very high resolution
   Traffic control	-	o	+
   Regional environmental mapping	o	+	-
   Topographic map up-dates	o	+	-
   Agricultural mapping	-	+	o
   Tree census	-	+	o
   Urban planning	-	o	+
   Weather monitoring	+	-	-

   b. Construct a table to show the advantages and disadvantages for the use of low, medium to high and very high resolution image.

   	Low resolution	Medium to high resolution	Very high resolution
   Advantages	inexpensive very high temporal resolution for global monitoring and weather forecasting	medium expenses a lot of data available (also good time series) can monitor environmental changes etc.	can detect also small objects useful for urban planning, construction, defence, farming, etc.
   Disadvantages	can only detect large objects cannot see the polar regions	cannot detect smaller objects not suitable for urban planning	very expensive only available the last few years

2. The choice of satellite system is usually a compromise between cost and spatial resolution. Which satellite system's resolution would you need to...

   a. monitor the vegetation of a region?

   • For this purpose one would use medium to high resolution images, which are cheaper than very high resolution data and cover larger areas.
   • Landsat data provides widely spread and easily obtainable images. Images from different dates are still on record. These images have been available for the last 30 years.

   b. check the construction progress of an airport?

   • For monitoring the construction of an airport very high resolutions in meters are required.
   • Satellites such as Ikonos, QuickBird or SPOT can provide such data.

   c. draw the topography of a region?

   • For this purpose low resolution data covering an entire region is needed.
   • Satellites such as NOAA satellites or ASTER can provide such information.
3. Find main tasks and uses of the satellites Landsat, SPOT and QuickBird on the Internet.

• Landsat: Monitoring of the earth surface, vegetation, environmental monitoring and land cover classification etc.
• SPOT: Mapping, security and defence, farming and forestry, fisheries, land management and planning, geology and risk mitigation.
• QuickBird: Various applications, e.g. urban planning, natural disaster management, agriculture, forestry.