Rabu, 04 Maret 2009

Masking Citra Aqua/Terra MODIS

Masking Citra Aqua/Terra MODIS

Masking dilakukan dengan tujuan untuk membedakan daerah daratan, lautan dan daerah yang berawan.

The purpose of masking is to distinguish the land, sea and cloudy areas.


Proses masking daratan dan lautan dilakukan pada file Land/Sea Mask, menggunakan fasilitas Masking pada software ENVI 4.x.

This masking process using Land/Sea Mask file from MOD03....(Terra MODIS) atau MYD03....(Aqua MODIS) and processed using ENVI 4.x


Proses masking awan darat dan awan laut dilakukan pada saluran 3, dimana :
Untuk tutupan awan :
- Nilai batas awan laut adalah 0.174
- Nilai batas awan darat adalah 0.2

To do masking process land cloud and sea cloud use band 3 MODIS, where:
Threshold Value for sea cloud is 0.174
Threshold Value for land cloud is 0.2



Langkah-langkah pemrosesan masking citra MODIS menggunakan software ENVI 4.x

Below are the steps in masking process for Land/Sea Mask MODIS data with ENVI 4.x :

1. Open MOD03....(Terra MODIS) atau MYD03....(Aqua MODIS) from mainmenu ENVI:
File -> Open External File -> Generic Format -> HDF
2. Choose your file and choose Land/Sea Mask
3. Choose Map -> Georefence MODIS (to georeferencing land/sea mask data)
4. Follow the instruction..choose latitude and longitude...Choose Geographic Lat/Lon, Perform Bow-Tie Correction = YES, and then click OK
5. Choose your output file name and location..wait the process...(Building MODIS Image Geometry...Georeferencing MODIS with Bow-Tie Correction), and then you will have your land/sea mask image georeferenced in Available Bands List
6. Open the Image, and move your mouse, click on Land and see the value...
7. to build Mask..use tool from Main Menu choose Basic Tools -> Masking -> Build Mask
8. choose Display#1 (display that showing the Georeferenced Land/Sea Mask Data), click OK
9. Mask Definition, choose Option - Import Data Range (Choose Georeferenced land/sea mask filename)
make two mask definition : first, min = 0 and max = 0
then, min = 3 and max = 7
10. After that, click Aplly and u will get the Mask.....

best regards
geografi..putra bumi..
http://ajiputrap.blogspot.com/

4 komentar:

  1. Makasih atas ilmunya..
    Tapi aku mau tanaya, proses maskingnya sama gak dengen jenis citra lainnya???

    Maksih sebelumnya...

    BalasHapus
  2. at least sama...hanya tinggal memasukkan paramater darat-awan, laut-awan

    BalasHapus
  3. salam boleh ajar macam mana mau masking daratan..?? menggunakan software erdas8.5 data image landsat?? email kan kepada saya atau ajar melalui blog ini?

    BalasHapus
  4. salam?boleh tolong ajar kan macam mana mau masking daratan menggunakan erdas8.5 data image landsat?tolong email kan kepada saya? illman_90@yahoo.com

    BalasHapus