عدة اسئلة في جمع النطاقات فى برنامج Envi

[يوسف رمضان]

السلام عليكم
هناك عدة اسئلة ارجو الاجابة عليها و لكم جزيل الشكر مقدما

1 - قمت بتحميل مرئية من نوع لاندسات ETM فى صيغة TIFF وطبعا كما تعلمون هى عبارة عن 9Bands و اعلم ان هناك 2bands حرارى 61 & 62 وهما ذو درجة وضوح مختلفة عن باقى البندات هذا بالاضافة الى band8 وهو ايضا ذو درجة وضوح مختلفة 15م و السؤال هو كيفية تجميع هذه البندات اعرف ان باند 8 مستبعد و يستخدم فقط عند عمل merge ولكن سؤالى خاص بالباند 61 & 62 فهل يتم اضافتهما مع اختلاف درجة وضوحهما عن باقى البندات
2 - كيقيه عمل Calibration على برنامج Envi حيث بعد تجميع الصورة احاول عملها و لكن لا تتم لوجود خطأ
3 - عندما احاول عمل vegetation index يقول ان الصورة لا يوجد بها wavelength فادخلها عن طريق Edit heder ولكن ايضا لا تتم العملية و لا اعرف اين الخطأ
ارجو ان تتكرموا بالاجابة للأهمية و لكم جزيل الشكر

[يوسف رمضان]

الأخ الفاضل / المشرف على المنتدى
الرجاء سرعة الاجابة على الاسئلة السابقة للاهمية، حتى لو كنتم ترون انها اسئلة نافهه لا تستحق الاجابة و لكنها مهمة بالنسبة لى لذا ارجو ان تتكرموا بسرعة الرد

[نجد جمال]

Calibration Utilities
Use Calibration Utilities to apply calibration factors to AVHRR, MSS, QuickBird, TM, TIMS, and WorldView-1 data, and to use a variety of atmospheric correction techniques.
AVHRR Calibration
Use the AVHRR calibration utility to calibrate AVHRR data from the NOAA-12, -14, -15, -16, -17, and -18 satellites. Bands 1 and 2 are calibrated to percent reflectance and bands 3, 4, and 5 are calibrated to brightness temperature, in degrees Kelvin. For details, see Calibrating AVHRR Data.
Landsat MSS Calibration
Use Landsat MSS calibration to convert Landsat MSS digital numbers to radiance or exoatmospheric reflectance (reflectance above the atmosphere) using published post-launch gains and offsets (see Landsat TM Calibration for more details):
From the ENVI main menu bar, select Basic Tools Preprocessing Calibration Utilities Landsat MSS. The Input File dialog appears.
Select an input file and perform optional Spatial Subsetting and/or Spectral Subsetting, then click OK. The MSS Calibration Parameters dialog appears.

From the Satellite drop-down list, select the satellite type.

Enter the data acquisition month, day, year, and sun angle into the appropriate fields.

Select the output type by selecting from the Radiance or Reflectance radio buttons.

Select output to File or Memory.

Click OK.
Landsat TM Calibration
Use Landsat TM calibration to convert Landsat TM or ETM digital numbers to radiance or exoatmospheric reflectance (reflectance above the atmosphere) using published post-launch gains and offsets (see http://landsat.usgs.gov/technical_de...bration_files/ and http://edcftp.cr.usgs.gov/pub/metada...e/landsat_etm/).
The spectral radiance (Ll) is calculated using the following equation:
where QCAL is the calibrated and quantized scaled radiance in units of digital numbers, LMINl is the spectral radiance at QCAL = 0, LMAXl is the spectral radiance at QCAL = QCALMAX, and QCALMAX is the range of the rescaled radiance in digital numbers. LMINl and LMAXl are derived from tables provided in the Landsat Technical Notes (August 1986) with the information provided through the TM Calibration Parameters dialog in ENVI. QCALMAX is 255 for all TM data and 127 for all MSS data except Band 4 (0.8 to 1.1 mm), which is 63 for certain time periods (data acquired before February 1, 1979 for Landsat 1-3 and processed before October 22, 1982). The resulting radiance (Ll) is in units of watts per square meter per steradian per micrometer (W/(m2*sr*mm)).
The exoatmospheric reflectance (rp) is calculated using the following equation:
where Ll is the spectral radiance, d is the Earth-Sun distance in astronomical units, ESUNl is the mean solar exoatmospheric irradiance, and qs is the solar zenith angle in degrees. ESUNl is derived from tables provided in the Landsat Technical Notes (August 1986). The resulting reflectance is unitless. See http://landsat.usgs.gov/dcidocuments/L5TMCal2003.pdf for further details.
TM band 6, if present, is converted to temperature. If 7 bands are input, the 6th band is assumed to be the thermal infrared band. If only 6 bands are input, then it is assumed that there is no thermal infrared band.
For Landsat 7 GeoTIFF files that do not contain calibration coefficients, you can use Landsat TM calibration to specify the calibration coefficients and other related parameters, or you can extract the parameters from a Web server.
Select one of the following options from the ENVI main menu bar:
Basic Tools Preprocessing Calibration Utilities Landsat TM
Basic Tools Preprocessing Data-Specific Utilities Landsat TM Landsat TM Calibration
Spectral Preprocessing Calibration Utilities Landsat TM
Spectral Preprocessing Data-Specific Utilities Landsat TM Landsat TM Calibration
The Input File dialog appears.

Select an input file and perform optional Spatial Subsetting and/or Spectral Subsetting, then click OK. The TM Calibration Parameters dialog appears.
For Landsat 7 HDF files, the data acquisition date information, gains and bias factors, and sun elevation and azimuth are automatically read from the header.

For Landsat 7 GeoTIFF files, you can obtain these parameters from the EROS Data Center as CPF files and MetaData files. You they may also acquire them through an ITT Visual Information Solutions web server (see step 3). The earth-sun distance used in Landsat-7 calibration is calculated from a table in the Landsat 7 User's Guide, dated May 1, 2001.

Choose from the following options:
Enter or change any of the parameters as necessary.

To download Landsat-7 parameters from the ITT Visual Information Solutions web server, use Get Calibration Parameters from Web, which is only available only when the file is in GeoTIFF format. You must have an active internet connection to use this option.

While a web browser can negotiate with the proxy server to access the ITT Visual Information Solutions site, ENVI establishes its own internet connection to the website and does not use a web browser. Your local network administrator may be able to allow your system to bypass the proxy to access the website. Currently, you cannot access this site through a firewall or proxy server. (If you try, your connection times out within 15 seconds.) See Manually Accessing Landsat-7 Calibration Parameters from the Web.

The information is obtained from the Web server and automatically entered into the corresponding fields.

If the input filename does not follow the Landsat 7 filenaming convention, the data acquisition date information defaults to January 1, 1984 and the sun elevation to 90 degrees. When the warning dialog appears, click OK. The TM Web Calibration Parameters dialog appears. Enter the original filename, or select the Date/Path/Row/Band button and enter the corresponding information.

The date, path, row, and band information is used to derive a filename based on the Landsat 7 naming convention.

Click OK.

For GeoTIFF files only, select an input band used for processing from the Data Acquisition Band drop-down list.

Select the output type using the Radiance or Reflectance radio buttons.

Provide Scale: Min and Scale: Max values if these values are not provided by a header or the Web server.

The minimum scale and maximum scale values are satellite parameters set for each band.ENVI uses these values to derive the gains and offsets.

Select output to File or Memory.

Click OK. When complete, ENVI adds the resulting output to the Available Bands List.

[نجد جمال]

is vegetation index NDVI?
NDVI
Normalized Difference Vegetation Index; a vegetation index used to transform multispectral data into a single image band whose values indicate the amount of green vegetation present in the pixel. ENVI uses the standard NDVI algorithm, where NIR is a near-infrared band:


IF YES

From the ENVI main menu bar, select Transform NDVI. The Input File dialog appears.
Select an input file and perform optional Spatial Subsetting, then click OK. The NDVI Calculation Parameters dialog appears.

Specify the Input File Type (TM, MSS, AVHRR, and so on) from the drop-down list. ENVI automatically enters the bands it uses to calculate the NDVI in the Red and Near IR fields.

To calculate the NDVI for a sensor type not listed in the drop-down list, enter the band numbers in the Red and Near IR fields.

Select output to File or Memory.

Select one of the following output types from the Output Data Type drop-down list.
Byte: Enter the Min and Max NDVI value in the fields supplied.

Floating Point

Click OK. ENVI adds the resulting output to the Available Bands List.

[محمد ابريك كروش]

شكرا للاخ نجد جمال علي الشرح
سؤال: ما هي الترجمة العربية الصحيحة لـلــ Vegetation Index ؟

علي العموم برنامج الادريسي يحوي موديل به 19 نوع من الاندكسات للغطاء النباتي وهي كالاتي :
Ratio
NDVI--Normalized Difference Vegetation Index
RVI--Ratio Vegetation Index
NRVI--Normalized Ratio Vegetation Index
TVI --Transformed Vegetation Index
CTVI --Corrected Transformed Vegetation Index
TTVI--Thiam's Transformed Vegetation Index
PVI--Perpendicular Vegetation Index
PVI1--Perpendicular Vegetation Index 1
PVI2--Perpendicular Vegetation Index 2
PVI3--Perpendicular Vegetation Index 3
DVI--Difference Vegetation Index
AVI--Ashburn Vegetation Index
SAVI--Soil-Adjusted Vegetation Index
TSAVI1--Transformed Soil-Adjusted Vegetation Index 1
TSAVI2--Transformed Soil-Adjusted Vegetation Index 2
MSAVI1--Modified Soil-Adjusted Vegetation Index 1
MSAVI2--Modified Soil-Adjusted Vegetation Index 2
WDVI--Weighted Difference Vegetation Index

وجميعها تحتاج الي Red and Infrared bands
بالنسبة للاندكس الثاني وهو NDVI فيحسب بأستخدام المعادلة الاتية ؟

( NDVI= ( NIR-R ) / ( NIR+R

والبقية كل منها لها معادلتها الخاصة التي يمكن الرجوع اليها في الكتب او الدليل المرافق للبرنامج ..اما عند تطبيق هذه العمليات فالبرنامج (مثلاُ الادريسي ) يحسبها ويعطيك النتيجة دون اظهار هذه المعادلة

تحياتي للجميع

[يوسف رمضان]

شكرا أخى الكريم.....و لكن
انا لا اسأل عن طريقة عمل برنامج ENVI او كيفية عمل calibration أو طريقة عمل vegetation index عليه و لكن احتاج الى اجابة على اسئلتى من خلال خبرتكم من خلال المارسسة بمعنى اننى عملت calibration لصورة لاندسات حيث قمت بعمل calibration لكل باند على حده و اعتقد ان هذا هو الصحيح و لكن فوجئت بأن حجم الصورة اصبح حولى 1.5 جيجا و لا ادرى ان كانت هذه الطريقة صحيحة ام لا و هل هناك امكانية لعمل calibration بعد تجميع الصورة
اما بالنسبة للسؤال الثانى فعن كيفية ادخال waveleangh و ليس طريقة عمل vegeta tion index
اكيد انا شاكر لك جدا وشاكر على مجهودك و اتمنى من الله ان اجد عندك الاجابة على اسئلتى ولكم جزيل الشكر

[يوسف رمضان]

السلام عليكم
انتظر اجابة على اسئلتى من الدكتور وسام الدين محمد فهل اجد الاجابة فى القريب العاجل