# Tagged Questions

An Earth Observation Satellite.

1answer
56 views

### Why different SPOT5 histograms from two versions of same SPOT5 raster?

I have encountered a, to me, strange behaviour in the histogram function of QGIS (2.2.0 Valmiera on Windows 7). Basically the same image produces totally different histograms. I might have missed ...
1answer
65 views

### Extracting spectral values

I'm busy working on a project and I have orthorectified and atmospherically corrected SPOT5 images. We now need to create a point shapefile and then extract the spectral value of the cell at that ...
1answer
154 views

### Low top of canopy surface reflectance values

I have calculated at sensor reflectance for a multispectral image and performed atmospheric correction. The reflectance values for the visible and NIR bands are between 0.2 to 0.01 for surfaces, ...
1answer
516 views

### Spot 6 - Reflectance calibration

I have a Spot-6 image and the metadata contain 9 values of SUN_ELEVATION (BottomRight BottomCenter BottomLeft CenterRight Center CenterLeft TopRight TopCenter TopLeft). I've used before Landsat and ...
1answer
300 views

### Mosaicking NDVI images from different scenes

I have six overlapping NDVI images derived from atmospherically corrected SPOT5 images, all from the same date. How can I mosaic the images perfectly without seeing any differences between the same ...
0answers
600 views

### Calculating TOA reflectance from Radiance using Erdas Imagine for a Spot2 image

Using the SPOT equation ρ = π L/[E cos (θs) d-²] to calculate TOA reflectance from Radiance. L was calculated using this equation [L = (X/A) + B] d was calculated by converting date to julian day ...
1answer
561 views

### Erdas Imagine DN to TOA reflectance for SPOT images

I would like to convet DN to TOA reflectance in Erdas Imagine 2013. I see there is a way of doing this for Landsat7 in the Radiometric tab. How can I do this for SPOT2,4,5 images?
1answer
680 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.
1answer
193 views

### How does i.fusion.brovey in Grass 6.4.3 work?

I'm using Grass 6.4.3 in Linuxmint 16. I don't have a very big problem but I'm trying to understand what is Grass doing, if I'm applying the process correctly and if there is something wrong with my ...
0answers
227 views

### Advice on colour balancing a SPOT5 ArcGIS Mosaic Dataset

All, I'm working on a project using satellite imagery of a large braided river. I've been provide lots of SPOT5 images (that overlap). I've created a geodatabase, created a mosaic dataset, added the ...