{"id":1442,"date":"2015-07-19T02:33:16","date_gmt":"2015-07-19T02:33:16","guid":{"rendered":"https:\/\/grindgis.com\/?p=1442"},"modified":"2015-08-28T12:43:56","modified_gmt":"2015-08-28T12:43:56","slug":"slc-correction-landsat-7-qgis-erdas-imagine","status":"publish","type":"post","link":"https:\/\/grindgis.com\/?p=1442","title":{"rendered":"Layer Stacking and SLC correction of Landsat 7 image using QGIS and Erdas IMAGINE software"},"content":{"rendered":"

[vc_row layout=”normal” margintop=”0″ marginbottom=”15″ paddingtop=”0″ paddingbottom=”0″ bg_color=”#ffffff” bg_repeat=”repeat” bg_stretch=”no” en_border=”no” border_color=”#e8e8e8″][vc_column width=”1\/1″][vc_column_text]Table of Contents:<\/span><\/strong><\/p>\n

Using ERDAS Imagine SLC Correction:<\/strong><\/p>\n

Process 1: \u00a0Layer stack Bands<\/a><\/p>\n

Process 2: \u00a0SLC correction<\/a><\/p>\n

Using QGIS 2.0\u00a0SLC Correction:<\/strong><\/p>\n

Process 1: \u00a0Layer stack\/merge the file<\/a><\/p>\n

Process 2: \u00a0SLC correction<\/a><\/p>\n

Process 3: \u00a0Layer stack \/merge the SLC corrected band<\/a>[\/vc_column_text][\/vc_column][\/vc_row][vc_row layout=”normal” margintop=”0″ marginbottom=”15″ paddingtop=”0″ paddingbottom=”0″ bg_color=”#ffffff” bg_repeat=”repeat” bg_stretch=”no” en_border=”no” border_color=”#e8e8e8″][vc_column width=”1\/1″][vc_column_text]<\/p>\n

Landsat 7, launched on April 15th<\/sup> 1999 with Advanced Enhanced Thematic Mapper Plus (ETM+) sensor. Unfortunately on May 31st<\/sup> 2003 the SLC (Scan line corrector) in the ETM+ instrument failed which\u00a0leads to the stripping or missing of scan line in the satellite image. Various techniques are available for the\u00a0SLC correction. Most of the remote sensing\u00a0software package includes a separate module for it. On this tutorial\u00a0we are using two software,\u00a0one is an open source, QGIS and next is commercial,\u00a0ERDAS\u00a0Imagine 9.1 . Even though Landsat 8 is launched recently which is SLC error free, still Landsat 7 image is important for remote sensing analysis. The table below shows spectral characteristics of ETM+ sensor.<\/p>\n

[\/vc_column_text][\/vc_column][\/vc_row][vc_row layout=”normal” margintop=”0″ marginbottom=”15″ paddingtop=”0″ paddingbottom=”0″ bg_color=”#ffffff” bg_repeat=”repeat” bg_stretch=”no” en_border=”no” border_color=”#e8e8e8″][vc_column width=”1\/1″][vc_column_text]<\/p>\n

\n\n\n\n\n\n\n\n\n\n\n\n\n
\n

Enhanced<\/span><\/strong><\/p>\n

Thematic<\/strong><\/p>\n

Mapper<\/strong><\/p>\n

Plus<\/strong><\/p>\n

(ETM+)<\/strong><\/td>\n

\n

Landsat\u00a07<\/span><\/b><\/p>\n<\/td>\n

\n

Wavelength
\n(micrometers)<\/span><\/b><\/p>\n<\/td>\n

\n

Resolution
\n(meters)<\/span><\/b><\/p>\n<\/td>\n

<\/td>\n<\/tr>\n
<\/td>\n<\/tr>\n
\n

Band 1<\/span><\/p>\n<\/td>\n

\n

0.45-0.52<\/span><\/p>\n<\/td>\n

\n

30<\/span><\/p>\n<\/td>\n

<\/td>\n<\/tr>\n
\n

Band 2<\/span><\/p>\n<\/td>\n

\n

0.52-0.60<\/span><\/p>\n<\/td>\n

\n

30<\/span><\/p>\n<\/td>\n

<\/td>\n<\/tr>\n
\n

Band 3<\/span><\/p>\n<\/td>\n

\n

0.63-0.69<\/span><\/p>\n<\/td>\n

\n

30<\/span><\/p>\n<\/td>\n

<\/td>\n<\/tr>\n
\n

Band 4<\/span><\/p>\n<\/td>\n

\n

0.77-0.90<\/span><\/p>\n<\/td>\n

\n

30<\/span><\/p>\n<\/td>\n

<\/td>\n<\/tr>\n
\n

Band 5<\/span><\/p>\n<\/td>\n

\n

1.55-1.75<\/span><\/p>\n<\/td>\n

\n

30<\/span><\/p>\n<\/td>\n

<\/td>\n<\/tr>\n
\n

Band 6<\/span><\/p>\n<\/td>\n

\n

10.40-12.50<\/span><\/p>\n<\/td>\n

\n

60 * (30)<\/span><\/p>\n<\/td>\n

<\/td>\n<\/tr>\n
\n

Band 7<\/span><\/p>\n<\/td>\n

\n

2.09-2.35<\/span><\/p>\n<\/td>\n

\n

30<\/span><\/p>\n<\/td>\n

<\/td>\n<\/tr>\n
\n

Band 8<\/span><\/p>\n<\/td>\n

\n

.52-.90<\/span><\/p>\n<\/td>\n

\n

15<\/span><\/p>\n<\/td>\n

<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

(USGS website)<\/p>\n<\/div>\n

[\/vc_column_text][\/vc_column][\/vc_row][vc_row layout=”normal” margintop=”0″ marginbottom=”15″ paddingtop=”0″ paddingbottom=”0″ bg_color=”#ffffff” bg_repeat=”repeat” bg_stretch=”no” en_border=”no” border_color=”#e8e8e8″][vc_column width=”1\/1″][vc_column_text]<\/p>\n

Here we are using the Landsat 7 ETM+ image downloaded from GLCF website (http:\/\/glcf.umd.edu\/data\/landsat\/<\/a>). The data is\u00a0in .zip format, unzip the folder using any zip software. It\u00a0has 2 folders, one with all\u00a0the bands (from 1 to 8) and next is\u00a0gap masking files for each\u00a0band (We will use this files later for the gap filling).<\/p>\n

[\/vc_column_text][\/vc_column][\/vc_row][vc_row layout=”normal” margintop=”0″ marginbottom=”15″ paddingtop=”0″ paddingbottom=”0″ bg_color=”#ffffff” bg_repeat=”repeat” bg_stretch=”no” en_border=”no” border_color=”#e8e8e8″][vc_column width=”1\/1″][vc_column_text]<\/a><\/p>\n

SLC correction Using Erdas Imagine 9.1<\/strong><\/h2>\n

Process 1:<\/span> Layer stack for Bands<\/strong><\/p>\n

Open the Erdas Imagine Software- click on \u201cImage Interpreter\u201d<\/strong> from the main toolset\u00a0>Select \u201cUtilities\u201d
\nAnd \u00a0then Click on \u201cLayer stack\u201d<\/strong> tool<\/p>\n

\"Layer<\/p>\n

When you select the \u201clayer stack\u201d<\/strong> tool a separate small window will open<\/p>\n

a.<\/strong> Select \u201cInput file\u201d<\/strong> and navigate to\u00a0the downloaded folder with Landsat 7\u00a0data and select the first\u00a0band and click on \u201cADD\u201d<\/strong> button in the Layer stack window.(Change the file type to \u201cTiff\u201d <\/strong>format because the satellite image will be in Tiff format).<\/p>\n

b.<\/strong> Simultaneously add all the bands (bands that\u00a0you want for your application) and click \u201cADD\u201d button, you will notice\u00a0all added bands<\/p>\n

c.<\/strong> Change the \u201cLayer\u201d<\/strong> 1 into all<\/p>\n

d.<\/strong> Set the Output folder and file name<\/p>\n

e.<\/strong> Select \u201cIgnore Zero in stats\u201d<\/strong><\/p>\n

f.<\/strong> Press \u201cOK\u201d<\/strong><\/p><\/blockquote>\n

\"Layer
\nLayer stacking window<\/p>\n

Open the layer stacked image in the Viewer<\/strong><\/p>\n

\"Viewer\"
\nLandsat 7 layer stacked with non SLC correction[\/vc_column_text][\/vc_column][\/vc_row][vc_row layout=”normal” margintop=”0″ marginbottom=”15″ paddingtop=”0″ paddingbottom=”0″ bg_color=”#ffffff” bg_repeat=”repeat” bg_stretch=”no” en_border=”no” border_color=”#e8e8e8″][vc_column width=”1\/1″][vc_column_text]<\/a>
\nProcess 2:<\/span> SLC correction through focal analysis <\/strong><\/strong><\/p>\n

a.<\/strong> Select \u201cSpatial enhancement\u201d<\/strong>\u00a0 from the \u201c Interpreter tool\u201d in main tool set<\/p>\n

b.<\/strong> From the \u201cSpatial enhancement\u201d<\/strong> select \u201cFocal analysis\u201d<\/strong> tool<\/p>\n

c.<\/strong> Separate Focal analysis window will open<\/p><\/blockquote>\n

\"SLC<\/p>\n

a.<\/strong> In focal analysis window Set the \u201coutput folder and file\u201d<\/strong> (Give layer stacked image as input)<\/p>\n

b.<\/strong> Set \u201coutput folder and name\u201d<\/strong><\/p>\n

c.<\/strong> Set \u201coutput data type\u201d<\/strong> as unsigned 8 bit<\/em><\/p>\n

d.<\/strong> Tick on \u201cignore Zero in stats<\/em>\u201d<\/strong><\/p>\n

e.<\/strong> From the drop down menu Set \u201cIgnore Specified values and \u201cApply only Specified values<\/strong><\/em>\u201d<\/strong><\/p>\n

f.<\/strong> Leave the values as Zero<\/p>\n

g.<\/strong> Press \u201cOK\u201d<\/strong><\/p><\/blockquote>\n

\"focal
\nFocal analysis window to perform SLC correction<\/p>\n

\"LC
\nModeler will start to run<\/strong><\/p>\n

h.<\/strong> After completing this process. Repeat the same process at least 6 or 7 times.<\/p>\n

i.<\/strong> Each time the previous output should be the input for the next time.<\/p><\/blockquote>\n

\"viewer\"
\nFirst output<\/p>\n

\"viewer\"
\nThird output<\/p>\n

\"output
\nPre SLC correction<\/p>\n

\"output
\nPost SLC correction (final the output)[\/vc_column_text][\/vc_column][\/vc_row][vc_row layout=”normal” margintop=”0″ marginbottom=”15″ paddingtop=”0″ paddingbottom=”0″ bg_color=”#ffffff” bg_repeat=”repeat” bg_stretch=”no” en_border=”no” border_color=”#e8e8e8″][vc_column width=”1\/1″][vc_column_text]<\/a><\/p>\n

SLC correction Using\u00a0QGIS 2.0<\/strong><\/h2>\n

Process 1:<\/span> Layer stack \/ merge the file<\/strong><\/p>\n

a.<\/strong> Open QGIS Desktop<\/p>\n

b.<\/strong> Click on \u201craster\u201d-\u201cMiscellaneous\u201d- select \u201cmerge tool\u201d<\/strong><\/p>\n

c.<\/strong> Separate window for merge will open<\/p><\/blockquote>\n

\"QGIS<\/p>\n

a.<\/strong> Set the \u201cinput files\u201d<\/strong> (Give the Landsat 7 bands)<\/p>\n

b.<\/strong> Set the \u201cOutput file and folder\u201d<\/strong><\/p>\n

c.<\/strong> Tick on \u201cLayer stack\u201d<\/strong><\/p>\n

d.<\/strong> Click \u201cOK\u201d<\/strong><\/p><\/blockquote>\n

\"QGIS
\nMerge window to perform Layer stacking<\/p>\n

a.<\/strong> Open the layer stacked\/merged image in QGIS<\/p><\/blockquote>\n

\"QGIS
\nLayer stacked image with SLC failure[\/vc_column_text][\/vc_column][\/vc_row][vc_row layout=”normal” margintop=”0″ marginbottom=”15″ paddingtop=”0″ paddingbottom=”0″ bg_color=”#ffffff” bg_repeat=”repeat” bg_stretch=”no” en_border=”no” border_color=”#e8e8e8″][vc_column width=”1\/1″][vc_message color=”warning”]<\/p>\n

Unlike Erdas Imagine here we have to do SLC correction for each bands using Gap masking file.<\/span><\/strong><\/p>\n

[\/vc_message][\/vc_column][\/vc_row][vc_row layout=”normal” margintop=”0″ marginbottom=”15″ paddingtop=”0″ paddingbottom=”0″ bg_color=”#ffffff” bg_repeat=”repeat” bg_stretch=”no” en_border=”no” border_color=”#e8e8e8″][vc_column width=”1\/1″][vc_column_text]<\/a>
\nProcess 2:<\/span>\u00a0SLC Correction<\/strong><\/p>\n

a.<\/strong> Select \u201canalysis\u201d<\/strong> from the \u201cRaster\u201d<\/strong>-and click on \u201cFill Nodata\u201d<\/strong> tool<\/p>\n

b.<\/strong> Separate Window for \u201cFill Nodata\u201d<\/strong> will open<\/p><\/blockquote>\n

\"SLC
\nFrom the Fill Nodata window<\/p>\n

a.<\/strong> Set \u201cInput folder and file\u201d <\/strong>\u00a0(Layer stacked image)<\/p>\n

b.<\/strong> Set \u201cOutput file and folder\u201d<\/strong><\/p>\n

c.<\/strong> Tick on \u201c Search distance and set it 100\u201d<\/strong><\/p>\n

d.<\/strong> Tick on \u201cBand to Operate\u201d<\/strong> and set the band number as 1 (Later change it to 2,3,4,5 for other bands).<\/p>\n

e.<\/strong> Tick on \u201cValidity mask\u201d<\/strong> and browse\u00a0the appropriate mask file for each band (Mask files for each band should be included\u00a0with the downloaded Landsat 7 image folder .)<\/p>\n

f.<\/strong> Tick on do not use the default validity mask<\/strong><\/p>\n

g.\u00a0<\/strong>Press \u201cOK\u201d<\/strong><\/p><\/blockquote>\n

\"fill
\nFill No data window to perform SLC correction<\/p>\n

\"SLC
\nSLC corrected Image of Band 1<\/p>\n

\"SLC
\nSLC corrected Image of Band 3
\nCorrect all bands using the same tool and method.<\/strong>[\/vc_column_text][\/vc_column][\/vc_row][vc_row layout=”normal” margintop=”0″ marginbottom=”15″ paddingtop=”0″ paddingbottom=”0″ bg_color=”#ffffff” bg_repeat=”repeat” bg_stretch=”no” en_border=”no” border_color=”#e8e8e8″][vc_column width=”1\/1″][vc_column_text]<\/a>
\nProcess 3:<\/span>\u00a0Layer Stack \/ merge the SLC corrected band<\/strong><\/p>\n

a.<\/strong> Layer stack the SLC corrected Landsat 7 bands using the method mentioned in Process 1<\/strong><\/p><\/blockquote>\n

\"SLC
\nSLC corrected and Layer stacked image.[\/vc_column_text][\/vc_column][\/vc_row][vc_row layout=”normal” margintop=”0″ marginbottom=”15″ paddingtop=”0″ paddingbottom=”0″ bg_color=”#ffffff” bg_repeat=”repeat” bg_stretch=”no” en_border=”no” border_color=”#e8e8e8″][vc_column width=”1\/1″][vc_separator style=”solid” padding_top=”0″ padding_bottom=”0″][\/vc_column][\/vc_row][vc_row layout=”normal” margintop=”0″ marginbottom=”15″ paddingtop=”0″ paddingbottom=”0″ bg_color=”#ffffff” bg_repeat=”repeat” bg_stretch=”no” en_border=”no” border_color=”#e8e8e8″][vc_column width=”1\/1″][vc_column_text]References:<\/p>\n

http:\/\/landsat.usgs.gov\/<\/a><\/em><\/p>\n

http:\/\/www.hexagongeospatial.com\/<\/a><\/em><\/p>\n

http:\/\/www.qgis.org\/en\/site\/<\/a><\/em><\/p>\n

http:\/\/gis.stackexchange.com\/<\/a><\/em>[\/vc_column_text][\/vc_column][\/vc_row][vc_row layout=”normal” margintop=”0″ marginbottom=”15″ paddingtop=”0″ paddingbottom=”0″ bg_color=”#ffffff” bg_repeat=”repeat” bg_stretch=”no” en_border=”no” border_color=”#e8e8e8″][vc_column width=”1\/1″][tagline_box action_box_style=”style1″ call_text=”NOW READ:” call_text_small=”Calculating the Vegetation Indices from Landsat 8 image Using ArcGis 10.1″ title=”READ” target=”_self” color=”blue” size=”small” margin=”0″ href=”https:\/\/grindgis.com\/blog\/vegetation-indices-arcgis”][\/vc_column][\/vc_row]<\/p>\n","protected":false},"excerpt":{"rendered":"

[vc_row layout=”normal” margintop=”0″ marginbottom=”15″ paddingtop=”0″ paddingbottom=”0″ bg_color=”#ffffff” bg_repeat=”repeat” bg_stretch=”no” en_border=”no” border_color=”#e8e8e8″][vc_column width=”1\/1″][vc_column_text]Table of Contents: Using ERDAS Imagine SLC Correction: Process 1: \u00a0Layer stack Bands Process 2: \u00a0SLC correction Using QGIS 2.0\u00a0SLC Correction: Process 1: \u00a0Layer stack\/merge the file Process 2: \u00a0SLC correction Process 3: \u00a0Layer stack \/merge the SLC corrected band[\/vc_column_text][\/vc_column][\/vc_row][vc_row layout=”normal” margintop=”0″ marginbottom=”15″ paddingtop=”0″ […]<\/p>\n","protected":false},"author":1,"featured_media":1462,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4,288],"tags":[313,308,307,301,312,309,315,311,310,314],"class_list":["post-1442","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog","category-remote-sensing","tag-detail-tutorial","tag-erdas-imagine","tag-landsat-7","tag-landsat-8","tag-layer-stack-bands","tag-qgis","tag-scan-line-corrector","tag-slc-correction","tag-slc-error","tag-slc-problem-tutorial","entry","has-media"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t