ALOS Data Visualization and Map Preparation. - Hands on Exercise 01-

Transcription

1 ALOS Data Visualization and Map Preparation - Hands on Exercise 01- Dr. Lal Samarakoon, Kavinda Gunasekara (Geoinformatics Center/AIT) Mokoto Kawai (JAXA/Japan)

2 Content Hands on Exercise 1. Details of MultiSpec software 2. Launch of MultiSpec software 3. ALOS Image Visualization & Enhancement i. About TIFF, GeoTIFF and CEOS format ii. Open AVNIR-2 GeoTIFF image iii. True Color Composite image iv. Image histogram v. Image enhancement vi. Image zooming vii. Open AVNIR-2 CEOS format viii. Band staking ix. Export to GeoTIFF

3 4. Map preparation example China Earthquake i. Open post disaster image ii. iii. iv. Setup the image parameters for Geo-link images Open pre disaster image Setup the image parameters for Geo-link images v. Selecting same area in post and pre disaster images using Geo-linking option vi. Save sub-set of selected area as GeoTIFF format vii. Prepare a map in Microsoft Power Point using provided guide map, scale bar, north arrow, details, etc 5. Self exercise Do it by yourself

4 Details of MultiSpec Software Freely downloadable at

5 Quick Launch - MultiSpec Software D: SAS_Training MultiSpe c Double Click

6 ALOS Images Visualization & Enhancement Available data formats GeoTiff CEOS

7 GeoTIFF and TIFF TIFF format is the most popular and versatile Raster data format. TIFF is a format for storage, transfer, display, and printing of raster images, such as clipart, scanned documents and today map information, too. GeoTIFF refers to TIFF Format files which have geographic data embedded as tags within the TIFF file. The geographic data can then be used to position the image in the correct location and geometry of a other geographic data. This is a metadata format, which provides geographic information to associate with the image data.

8 CEOS Format The native data format for ALOS products in most data distributors could be CEOS. This format is a mixed ascii and binary format which may not be well supported in your image processingvpackage. For novice users it is recommended that you chose the GeoTIFF format in your processing options when you order your products. Sentinel Asia Project considers providing emergency observation data in GeoTIFF format.

9 3.ii GeoTIFF format (AVNIR-2) visualization 1 File a Open Image 2 Browse D: SAS_Training GIC_Materials GeoTIFF Stacked image Three Channels 3

10 AVNIR-2 True Color Composite image True Color Composite Screen Color RS Data 1 2 Red Green Blue Red Green Blue

11 AVNIR-2 TCC image

12 Histogram of Satellite Data 1. Reflected energy from earth surface is converted to a digital value at the sensor of a satellite. 2. Energy level is converted to Digital value; In the case of ALOS to 255 discrete levels = 8bit; 4. For each Pixel (observed on the ground) a value between is assigned based on the strength of energy received at the sensor. 5. Histogram shows how the values between are distributed for a given image. Similar to frequency distribution. Frequency Gray Levels

13 Image Enhancement Refers to color enhancement of image display. Better quality for visual understanding. Stretch the distribution of digital values to take the whole depth of the display; 0 to 255 Distribution can be viewed from histogram Distribution of reflected energy (digital number) depends on various factors and not always the same. There are various ways to achieve the enhancement including simple linear stretch.

14 Observation & Display Reflectance Screen Color Low Dark Reflectance: Energy at the sensor High Bright 0 Digital Number

15 Sample Histogram Frequency Characteristics? 0 Gray Levels 255

16 Image Enhancement Original Histogram Adjusted Histogram to color enhancement

17 Enhancement process MutiSpec Software provides with 3 different methods; Linear, Equal Area, Gaussian Select one of them Once a method is selected, it will apply for all 3: Red, Green, and Blue displays changing the dynamic range. In this example all the 3 bands of ALOS receives same enhancement function

18 Image Enhancement 1 Processor a Display Image

19 Image Enhancement cont.

20 AVNIR-2 Enhanced TCC image

21 Image zoom in Click this button to zoom in

22 Image zoom out Click this button to zoom out Try with both buttons zoom in and zoom out while holding Ctrl key

23 3.vii AVNIR-2 (CEOS format) Visualization 1 File a Open Image 2 Browse D: SAS_Training GIC_Materials CEOS Channel 01 - Blue 4 Summary file Product:AVNIR-2(1B2R) 3 5

24 Summary file

25 Calculating Histogram

26 Single Channel

27 Stacking Green Channel on to the same window 1 File a Open Image Green Channel 3 4 2

28 Stacking Red Channel on to the same window Red Channel 1 2

29 Stacking NearIR Channel on to the same window NIR Channel 1 2

30 Closing image open window Click Cancel

31 TCC image - R(Channel3), G(Channel2), B(Channel1) 1 Processor a Display Image 2 3

32 Three Channels

33 Exporting to GeoTIFF Format Processor a Reformat a Change Image File Format

34 1 2 3 Give a file name 4

35 4. Map Preparation China Earthquake Primary Disaster - Earthquake Secondary Disaster Flood due to landslide dam Location: Latitude- 31 o Longitude- 104 o Details of Satellite images Satellite: ALOS Sensor: AVNIR-2 Resolution: 10m Date of acquisition: 2008/06/04(post disaster) and 2007/03/31(pre disaster) Data source : JAXA

36 Major Steps Open Post Disaster Image Enhance the image if necessary Set image parameters to Geo-Link the images. Identify the area of interest in the Post Disaster Image Zoom out the area of interest Open Pre Disaster Image Set Image parameters to Geo-Link Identify the same area on Pre-Disaster image using Geo-Link function Save the selected area images (sub-set) as Geo-TIFF Import to Microsoft Power Point for map preparation

37 Open Post Disaster Image 2 D: SAS_Training GIC_Materials China_EQ R 1 File a Open Image 3 Post Disaster Image 4

38 1 2 3

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40 Geo-Link Images Image Map Parameters > set map coordinate specifications 1 Edit a Image Map Parameters 2 Keep default click OK 3

41 Open Coordinates View View a Coordinates View

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43 Identify coordinates Latitude x Longitude x.. Click and drag mouse pointer to select area

44 Click zoom in button

45 Disaster area

46 Open Pre Disaster Image to Geo-Link D: SAS_Training GIC_Material 1 File a Open Image 2 s China_EQR 3 Pre Disaster Image 5 Don t check this 4

47

48 ` Pre Disaster Image

49 Arrange both windows in same size use zoom in / zoom out buttons Click image window to activate use Scroll bars to pan image

50 Image Map Parameters - set map coordinate specifications 1 Edit a Image Map Parameters 2 Keep default click OK 3

51 Open Coordinates View

52 Method to select same area on both images Holding Ctrl key click and drag on post disaster image to select area on both images

53 2. Click zoom in button 1. Click image window to activate

54 Subset pre disaster image in to TIFF file 1 File a Save image selection to GeoTIFF AS. 2 Give a file name 3 4

55 Subset post disaster image in to TIFF file 1 Click post disaster image window to active 2 File a Save image selection to GeoTIFF AS. 3 Give a file name 4 5

56 Use Microsoft PowerPoint Package to Prepare Map Layout

57 Earthquake in China, May /03/31 (Pre-disaster) 2008/06/04 (Post-disaster) Landslides caused by earthquake Satellite/Sensor: ALOS/AVNIR-2 Data Provider: JAXA Image Interpreter: GIC/AIT Sentinel Asia

58 Double click filename.kml file of the generated subset...don t get surprised

59 A Value Added Product August 2008 Flood Map of Laos Details of Satellite images Satellite: ALOS Sensor: PALSAR ScanSAR Resolution: 100m Dates of acquisition: 2008/08/20(post) and 2007/08/18(pre) Data source : JAXA.METI

60 Pre Disaster Image (2007/08/18)

61 Post Disaster Image (2008/08/20)

62 Pre Disaster Image Post Disaster Image

63 RGB Color Assignment to PALSAR Image R: Pre Disaster Image (2007/08/18) G: Post Disaster Image (2008/08/20) B: Post disaster Image (2008/08/20)

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65 Vector Overlay

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67 An Other Value Added Product November 2008 Flood Map of Jaffna, Sri Lanka Details of Satellite images Satellite: ALOS Sensor: PALSAR Resolution: 6.25m Dates of acquisition: 2008/08/20(post) and 2007/08/18(pre) Data source : JAXA.METI

68 5rd Sentinel Asia System Training Program: 22nd-26th February 2010

69 Thank You. Geoinformatics Center Asian Institute of Technology Thailand

70 ALOS Data Products

71 ALOS Data Products

72 ALOS Data Products

73 PRISM Panchromatic Remote-sensing Instrument for Stereo Mapping μm Number of Optics : 3, AT +/ deg (Nadir / Forward / Backward) Base/Height ratio : 1.0 (F / B) Spatial resolution : 2.5m at Nadir Swath width : 35km at Triplet mode 70km at Nadir only Pointing angle : +/- 1.5 deg. S/N : >70, MTF : >0.20 Scanning method : Push broom Quantization : 8 bits Data compression : JPEG extension Observing geometry of triplet mode (OB1) Two observation (+/-1.20deg. pointing angle) per orbit are necessary for observing whole coverage by triplet mode except in high latitude areas. Nadir alone or nadir + backward modes (OB2)

74 AVNIR-2 Advanced Visible and Near Infrared Radiometer type 2 Band 1 : μm Band 2 : μm Band 3 : μm Band 4 : μm Field of view : 5.8 deg. Swath width : 70km at Nadir Instantaneous FOV : μrad Spatial resolution : 10m at Nadir Number of detectors : 7000 /band Pointing angle : +/- 44 deg. S/N : >200, MTF : >0.25 (1-3), >0.20 (4) Scanning method : Push broom Quantization : 8 bits 1,500 km Improvements in AVNIR-2 from AVNIR Resolution : 10m < 16m Pointing angle : +/-44 deg < +/-40 deg Calibration system : lamp 2 < lamp 1, Solar 1

75 PALSAR Phased Array type L-band Synthetic Aperture Radar L-band (1.27GHz) Fine Resolution Mode deg. HH or VV / HH+HV or VV+VH m / m 40-70km / 40-70km ScanSAR Mode deg. HH or VV / 100m / km Polarimetric Mode deg. HH + HV + VH + VV m / 20-60km