2
votes
1answer
55 views

Best Landsat band for forest classification?

Using Qgis and the Semi-Automatic Plugin for Classification, which are the best Landsat bands to use to classify trees species (in central Argentina)? In Landsat 5, 7 and 8?
1
vote
1answer
33 views

SPOT 2-5 convert DN to TOA using QGIS

I'm new to QGIS and I would like to convert SPOT(2-5) images from DN to TOA. How do I go about doing this? I've an idea of how to do it for Landsat images however I'm not sure about SPOT.
2
votes
1answer
49 views

Calculate EVI From Landsat 8 in QGIS [closed]

I have calculated atmospherically corrected reflectance values for Landsat 8. From that, I am getting correct values of NDVI in QGIS, but for EVI I am not getting the correct values. For some images ...
1
vote
2answers
31 views

How to calculate regrowth area?

Thanks to Best Landsat-5 TM band combination for detecting fire scars I am able to calculate burnt area in an absolute way (Normalized Burn Ratio). Does a ratio or delta operation exist to calculate ...
0
votes
0answers
38 views

NDVI from QGIS is giving me NaN values

NDVI,TTVI maps are nan values. when I do the NDVI calculation using the raster calculator it looks fine. what's going on?
1
vote
0answers
51 views

How to perform image classification with SemiAutomaticClassificationPlugin and BIP files?

I have multiband satellite images BIP format, Landsat TM/ETM containing 7/8 bands respectively along with a separate header file, some of them corrected by nearest neighbour classifier. I'm working ...
1
vote
2answers
137 views

Missing Dependency in SAGA. Orfeo Toolbox does not work

Hej guys, I am trying to perforem segmentation from Orfeo Toolbox (QGIS last version 2.2), whenever I try to use the toolbox, I get the following message: Oooops! The following output layers could ...
3
votes
1answer
285 views

How to build a confusion matrix for image classification using SAGA or QGIS?

I did a supervised classification of a Landsat image subset using my training data polygons. I used SAGA GIS for that and everything worked out fine. Now I am stuck since I have no clue how to ...
5
votes
1answer
971 views

Atmospheric Corrections for Landsat 8 OLI Using Orfeo Toolbox

I am trying to correct some Landsat 8 OLI imagery using the Orfeo Toolbox Optical Calibration tool via QGIS. I've retrieved data from Aeronet as well as relative spectral response data for the OLI ...
2
votes
0answers
336 views

Principal Component Analysis in QGIS

How do I go about to perform a band ratio and Principal Component analysis in QGIS? I need to derive principal components from ratios of landsat TM bands .
0
votes
2answers
782 views

Mysterious Problems with .IGE file [closed]

I'm trying to manipulate an .IGE file, which I understand is a raster data format developed by Erdas Imagine. The data I've downloaded is the National Land Cover Database (NLCD) 2006 Percent Developed ...
7
votes
2answers
356 views

How to perform enhancement operations on an satellite imagery in QGIS?

I am a new user of QGIS please suggest how to perform image enhancement operations on an satellite imagery like ratioing, contrast stretching, edge engancement, filtering etc. in QGIS?
7
votes
1answer
2k views

How to fill gaps in SLC-Off Landsat 7 ETM+ Images with QGIS?

Explanation of the problem: On 31 May 2003 the Landsat 7 Enhanced Thematic Mapper (ETM+) sensor had a failure of the Scan Line Corrector (SLC). Since that time all Landsat ETM+ images have had ...
2
votes
1answer
169 views

Sandbars feature extraction from satellite image

I want to know if we can analyse the permanancy of sandbars from a satellite image? Whether the formation of the sandbar is permanent or temporary.
2
votes
1answer
764 views

QGIS and satellite images band combination

When I add a satellite images as a raster in QGIS: 1. Why the image is changed, it looks like it has only one band?; 2. where is a tool for band combination? Thanks!