Collecting and interpreting information about the environment and the surface of the earth from a distance, primarily by sensing radiation that is naturally emitted or reflected by the earth's surface or from the atmosphere, or by sensing signals transmitted from a device and reflected back to it.

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6
votes
3answers
371 views

How to easily identify/classify coniferous forest from one date Landsat image?

I am pretty new in remote sensing and I am trying to identify/classify coniferous forest cover from single date Landsat scene. According to my preliminary web research I have these possibilities: ...
2
votes
1answer
23 views

Why does the resolution decrease with increasing incidence angle in the Sentinel-1 SAR sattelite

On this link (Sentinel1 webpage for a SLC product), the resolution is written as a range from the highest corresponding to low incidence angle, to the lowest resolution corresponding to high incidence ...
2
votes
1answer
66 views

Why does the peak of a mountain appear bright on Radar images

Why does the top of a mountain appear bright on a SAR (radar) image. I know that the peak of a mountain is subject to a layover effect, thus appearing closer on the radar image than the bottom part of ...
0
votes
1answer
14 views

How do you digitize an ROI in envi 5.2?

Is there a way to digitize an ROI in ENVI 5.2 that is larger than the area shown in the viewer? I'm setting up labs for an intro to RS class, and the next step is to subset the image to get rid of ...
2
votes
2answers
269 views

Spectral profile (z-profile) viewer for ArcGIS

I have multilayer raster with 6 bands. Is there a way to select one specific pixel and to display the z profile (the values of each band) for this pixel as a chart or table? I am looking for a tool ...
0
votes
3answers
236 views

What is an inexpensive way to map underground Utilities, like pipes, gas lines and telephone lines

I just got hired on to a small local government i am sill learning the ropes as a GIS Analyst. What is an inexpensive way to map underground Utilities, like pipes, gas lines and telephone lines? What ...
0
votes
0answers
16 views

Is this terminology I'm using is suitable for the field spatial analysis of time series?

I'm going to apply time series concepts to an satellite image, but instead of using time data located on the 'X' axis, I want to use spatial variations on that axis. In addition, the 'Y' axis keeps ...
4
votes
2answers
108 views

“Official” definition to hyperspectral sensor

I was checking in the literature about a formal definition for hyperspectral sensors, and the most complete definition I found was from The Center of Space Research (@ University of Texas in Austin): ...
2
votes
1answer
34 views

Difference between a spectroradiometer and multispectral sensor

Let's take as an example of a spectroradiometer MODIS, and as an example of a multispectral sensor the Landsat8 (OLI). What is the difference between these two sensors? Should we compare a ...
18
votes
10answers
11k views

What is the best open source software package for Remote Sensing?

Here are many questions with great answers about open source GIS software. I am wondering, what is the best open source software package for Remote Sensing? I would like to learn it and to use in my ...
1
vote
1answer
412 views

Masking clouds with Fmask

I have been trying to mask clouds with the quality control band with landsat 8 imagery. The problem I continue to run into is that the quality control bands mistake tops of buildings and concrete as ...
1
vote
1answer
30 views

Does satellite imagery have a unique azimuth for each of its spectral bands?

Does satellite imagery have a unique azimuth for each of its spectral bands? Is it right to say that if a sensor has 8 spectral bands, then it may have 8 different azimuth angle?
1
vote
0answers
26 views

Enhancing/smoothing Landsat 8 image using ArcGIS Online?

I understand that Landsat 8 is 30m resolution, but is there any technique that can be used to smooth/enhance the NDVI or Agriculture Landsat layers in an ArcGIS Online (AGOL) web map? I have adjusted ...
2
votes
0answers
19 views

Important to perform atmospheric correction when attempting to identify coral reefs?

I want to identify coral reefs using multi-temporal Landsat data and Lyzenga's Transformation method. In relation to pre-processing the image, should atmospheric correction be done or not? If not, ...
2
votes
1answer
49 views

Can a satellite go over the same area in different passes overtime

Can a sun-synchronous satellite (let's consider Sentinel-1) go over the same place, one time in an ascending pass and the next time (or few times after) in a descending pass?
0
votes
1answer
28 views

Extracting Data from Raster based on Aspect Raster file

I have 2 rasters, ones shows aspect and another shows date of snow thaw. I want to extract the date of snow melt based on values from the aspect raster. For example I want all the snow thaw dates from ...
1
vote
1answer
72 views

Python/GDAL hyperspectral Image wavelengths

I can open and read a hyperspectral image using GDAL according to the instructions brought by Max König here: So after reading the data like this : data = gdal.Open( filename ) then I can see ...
0
votes
0answers
39 views

DEM input problem using ARCSI Landsat 8 batch processing

I'm trying to use ARCSI in Linux to process a batch of Landsat 8 images. I'm using the arcsibuildcmdslist.py to build the arcsi.py final command. I'm having problems in the input DEM ...
0
votes
0answers
12 views

Difference in the definition of the radiometric resolution between a SAR and an optical sensor

Why is the definition of Radiometric resolution in Synthetic Aperture Radar (SAR) different from its simple definition in optical sensors (although both products are images in a numerical format or ...
3
votes
1answer
52 views

Reading Synthetic Aperture Radar raster images using python

Is it possible to read and modify Synthetic Aperture Radar raster images using python? gdal is not able to understand their Type which is Binary (application/octet-stream). One can find sample radar ...
1
vote
0answers
21 views

What does “Information [18]: Select at least one signature” in the semi automatic classification plugin mean?

I am using the semi automatic classification plug in to classify vegetation and water in a satellite image. I create training shp and signature list. When i hit "classification preview" it gives me ...
0
votes
0answers
19 views

Geometric correction using topographic maps?

I am researching LULC change detection using Landsat 7 etm + image in 2000 and Landsat 8 image in 2014. Both are L1T images. Do I need to do geometric correction using topographic map for my study ...
0
votes
0answers
16 views

What's the relationship between visibility and reflectance?

I'm having a problem with the atmospheric correction of remote sensing images. Until now I believed that increasing the visibility (or decreasing AOD) resulted in an increase in reflectance but now ...
1
vote
1answer
294 views

Is Landsat 4-5-7 L1G geometric corrected?

Im using Landsat L1G for our project and need L1G to be geometric corrected for later use. One thing I know for sure that L1G need to be employed a Digital Elevation Model (DEM) for topographic ...
2
votes
1answer
222 views

Classification, Change detection and NDVI Using (landsat2 MSS), (landsat5 TM), (Landsat7 ETM+) and (Landsat8 OLI)

I have 5 Landsat images for the same study area. One of them in 1975 (Landsat 2 MSS), two in 1985 and 1995 (Landsat 5 TM) and one in 2005 (Landsat 7 ETM+) and the last one in 2014 (Landsat8 OLI). I ...
2
votes
1answer
35 views

Get resolution and whether right/left looking from sentinel metadata

Is it possible in Sentinel hub products to know the resolution of the product and whether the SAR was right or left looking at the scene? I know that it's possible to know if the SAR was operating in ...
1
vote
0answers
51 views

What kind of raster mosaicking to use in land cover analysis

I have to mosaic two rasters (Landsat ETM+ scenes) to one single image and then analyse its land cover. Which option to use to avoid seeing a distinct line in the place where two different ...
2
votes
1answer
58 views

Is atmospheric correction necessary when working with multi-spectral indexes?

When you are working with Landsat Level 1 data and calculate indexes, e.g. NDVI, NDBI, SAVI ..., do you calculate them using raw data (pixel DN value), or atmospherically corrected data (surface ...
1
vote
1answer
73 views

Spectral Signature Extraction using landsat 7 and MODIS

I am working on differentiating cocoa plants from other vegetation types using 4 epoch bwt 1980-2010. I need to extract the spectral signature for cocoa plants and other known features. I plan using ...
1
vote
2answers
198 views

Accuracy assessment in eCognition

How to do accuracy assessment of classified images in ecognition? I have done the image segmentation for Worldview-2 image. Then, I have processed for classification for class names (e.g ...
2
votes
2answers
69 views

Raster image thresholding using python

I would appreciate if someone could guide me for applying thresholding technique to input raster image using Python. I intend to extract impervious surfaces from a high resolution raster such as ...
1
vote
0answers
18 views

Change detection between two Landsat scenes? [duplicate]

I want to do time series analysis and find change in NDVI. I have rasters where each pixel is represented by some value at a time. Also I have same thing but represented by points. And I would like ...
2
votes
2answers
88 views

land Use land cover classification

I am working on Land Use/Land Cover Classification of the Hindon river(India) watershed extracted using Aster DEM. Landsat 8 scenes had been used and mosaicked for the required AOI using the Watershed ...
2
votes
2answers
118 views

image segmentation of RGB image by K means clustering in python

I want to segment RGB images for land cover using k means clustering in such a fashion that the different regions of the image are marked by different colors and if possible boundaries are created ...
0
votes
3answers
153 views

Automated Forest Change Detection

Using two different time of images in the same places. Can i develop an automated change detection for forest area? What / which are the suitable software to used?
2
votes
2answers
108 views

How to atmospherically correct Landsat 8 data?

What is a simple way to atmospherically correct Landsat 8 data using Erdas 9.3 or ArcGIS 9.3?
0
votes
1answer
26 views

Semi Automated Classification plugin (QGIS) error when trying to create ROI

When I try to create a new ROI through Semi-Automated Classification plugin (SCP) for QGIS, I keep getting a message saying: "It appears that SciPy is not correctly installed. Please, see this page ...
3
votes
1answer
270 views

Applying pixel reliability mask to time series MOD13Q1

I am working with a 23-band GEOTiff in which each band is a 16-day MVC MODIS NDVI image. The MODIS .hdfs include a "pixel reliability" image with the following values: [-1]: Fill/No Data-Not ...
0
votes
1answer
25 views

comparison of atmopsheric correction methods

I have noticed that dos methods for atmospheric corrections are in the section of radiometric correction (i.toar) on grass gis.Does that means that dos is a method doing radiometric and atmospheric ...
1
vote
0answers
36 views

NDVI calculation using ArcGIS 10.1

i have to derive NDVI from Landsat 8 image.. I used the following equation from landsat website with band 5 and band 4 using ArcGIS 10.1 Conversion to TOA Radiance OLI and TIRS band data can be ...
11
votes
1answer
2k views

How to produce high-resolution DEMs from new Sentinel-1 data?

This is a general question relating to the new Sentinel-1 data. I'm interested in the potential for using this data to create high resolution DEMs in GIS (I use QGIS), to investigate archaeological ...
2
votes
1answer
38 views

Landsat Surface Reflectancce product Python packages

I have to work with numerous Landsat surface reflectance product that I downloaded from http://landsat.usgs.gov/CDR_LSR.php. The product comes with a QA data with information on clouds and shadows ...
3
votes
0answers
18 views

Should Endmembers be Normalized for Linear Unmixing?

In biological spectral microscopy, the standard in the field is to use normalized endmembers in linear unmixing algorithms. In most cases, the endmembers are normalized to the maximum value. I have ...
2
votes
3answers
846 views

Failed to create signature file

I need some help, because I've no clue how solve this issue the exercise that I'm trying to perform. The point where I'm stuck is 4. "Create signature file as LandsatCompS.sgs". I've done what it ...
3
votes
0answers
56 views

How to compute NDSI in ArcGIS for Desktop?

How do I compute a Normalized Difference Snow Index (NDSI) in ArcGIS's Raster Calculator? I have a Landsat 8 scene (hdf4 format) that contains derived surface reflectance band-by-band. Each band is a ...
2
votes
0answers
34 views

Which preprocessing comes first for pansharpened imagery- atmospheric correction or orthorectification?

For pansharpened imagery, what preprocessing method to do first- is it atmospheric correction or orthorectification? From my readings, it seems the former but the rational polynomial coefficients or ...
1
vote
1answer
107 views

Performing image segmentation in QGIS?

I have been trying to learn to work with QGIS (open-source GIS software) through some tutorials available online for classification of image for land cover. These tutorials used a dataset from Landsat ...
3
votes
0answers
46 views

From Landsat spectral radiance (W/m2*sr*µm) to Global horizontal irradiance (W/m2) for mere mortals

We are working in a solar energy project to locate potential sites for solar panel farms. We are using the Landsat 7 panchromatic band to derive radiance with GRASS using i.landsat.toar (W/m2*sr*µm ...
0
votes
0answers
42 views

Image formats to use for land cover classification in Python? [duplicate]

I am supposed to classify images for different land covers or land uses in Python. I read somewhere that the spectral module of Python is required to do the processing of Hyperspectral image data. ...
0
votes
1answer
58 views

Creating raster depicting landcover/use change in ArcMap?

How would I create a conversion matrix in ArcMap 10.2.2 to display the changes between two rasters (Land Use Land Cover Maps)? I have produced Land Use Cover Change maps from temporal satellite ...