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Exercise 1a: View Landsat image and overlay vector

In this exercise the following tools will be used:

  • gdal/ogr tools: ogr2ogr, openev

Create a directory for this exercise:

mkdir -p ${OUTPUTDIR}/exercise1

Open the Landsat image with an image viewer (e.g., openev)


Select different band settings (false colour images)

consult web page with landsat bands for different thematic band settings

Natural (true) colour for Landsat image: R=band 3(red), G=band 2 (green), B=band1 (blue)

Zoom in on particular area of interest

  • method 1: use + button
  • method 2: control button + drag window
  • method 3: control button + left mouse button

Zoom out

  • method 1: use - button
  • method 2: control button + right mouse button
  • method 3: use fit all layers button (square box with arrow in each corners)

Reproject water vector to epsg:3035 (ETRS89:LAEA)

ogr2ogr -t_srs epsg:3035 ${OUTPUTDIR}/exercise1/cornwall_water_3035.shp ${VECTORDIR}/cornwall_water.shp

Create vector with forested areas by selecting forest from natural vector and reprojecting to epsg:3035 (ETRS89:LAEA)

ogr2ogr -t_srs epsg:3035 -where "TYPE in ('forest')" ${OUTPUTDIR}/exercise1/cornwall_forest_3035.shp ${VECTORDIR}/cornwall_natural.shp

Open forest vector in openev on top of landsat raster image

Question: can you distinguish forest from other vegetated areas?

Question: can you easily distinguish forest from inland water?

Select the standard false colour composite for Landsat imagery

Consult web pages

Standard false colour settings for Landsat imagery: R=band 4(NIR), G=band 3(red), B=band2(green)
Do not forget to enhance raster after loading new band combination using the button with horizontal line

Question: What does vegetation look like in this false colour image, why?

Questions: What about water and forest now?

wiki/exercise1a.txt · Last modified: 2017/12/05 22:53 (external edit)