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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)

openev -h ${LANDSATDIR}/${LANDSATIMG}

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)