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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16 views

Asking linear regression between NDVI and LST using ENVI

Here I have a problem to calculate a linear regression. I Have two images of NDVI and LST derived from Landsat 8 and want to calculate the linear regression for between them obtaining the dry edge and ...
1
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1answer
20 views

Band Issues in Quickbird Satellite data

I procure data from DigitalGlobe (Quickbird Satellite data) for different periods hence data having some different band combination. I have attached an example image to show the problem. I am looking ...
7
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51 views

Automated detection of tracks

Given an area with depressions in open area from; say all terrain vehicles driving on soft surface. The vehicles will cause parallel depressions (paths) of about 10-20 centimeters in depth and around ...
0
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1answer
19 views

Which DOS method use to convert at-sensor radiance to at-surface values in GRASS (landsat data, i.landsat.toar modul)?

I am trying to calculate surface reflectance values from raw Landsat DN data downloaded from GLOVIS. I have imported Landsat data in GRASS 6 with header by i.landsat.import and reprojected the scene ...
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0answers
24 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 ...
4
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1answer
63 views

Identify shadow on Landsat image by Hillshade Tool (spatial analysis) in ArcGIS?

I would like to automaticaly identify shadows on Landsat scene in mountaineus area using Hillshade Tool (ArcGIS 10.1). I have 1 Landsat image from one date DEM (SRTM) from the same area To create ...
3
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0answers
19 views

How do I open MOD17A3 in ENVI such that it is properly georeferenced?

I am using ENVI 5.1 on Windows 8. I am trying to open a MOD17A3 (MODIS Net Primary Productivity standard product - L4) .hdf file which I downloaded from the USGS website. I am still a beginner at ...
3
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1answer
46 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: ...
3
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2answers
41 views

Is there a FTP to get Landsat images?

I need to automatically fetch Landsat images and for that it would be handy to access a ftp with images available. Does such ftp exist? Can I access it? Ultimately I want to get cloudless images. ...
4
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3answers
100 views

Extracting tree crown areas from remote sensing data (visual images and LiDAR)

I am looking for a method to process a remote sensing image and extract the crown areas of the individual trees from the image. I have both visual wavelength areal imagery, and lidar data from the ...
0
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1answer
31 views

Satellites to retrieve UV bands

I want to retrieve some satellite images with UV bands,Bun I don't know which satellites are providing UV bands and We can freely download them? I have already downloaded Modis and Landsat images,But ...
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1answer
23 views

Is TOA reflectance in floating point or DN? [closed]

After converting at radiance to TOA reflectance,is going to be in DN or floating point.
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2answers
19 views

How to load two images in ENVI 5.1?

I am using ENVI 5.1 and when I use the Data Manager to load several images and if I want to load two adjacent images, why would one of them load and the other doesn't?. Am I missing something here ?
2
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1answer
157 views

How to create NDVI map From LiDAR intensity and RGB image

I am new with GIS and I've been looking for ways on how I could create a NDVI map from LiDAR intensity and RGB image. Is there any way I could do this? I have read that you could create an intensity ...
2
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2answers
39 views

What reflectance curve

I was wondering to what surface that reflectance curve belongs. It is definetely no water or snow since their reflectance drops at a much smaller wavelength. I was thinking about a dense cloud but the ...
1
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0answers
22 views

TIMESAT Land cover class

Is it possible to monitor phenology of only 2 land cover classes in TIMESAT? Example is corn and wheat for 7 years. Sowing structure of this crops changes every year, i.e. their location on an image ...
0
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1answer
47 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
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1answer
34 views

Classifying type of land use each spectral represents from remote sensed data?

How do you know the type of land use each spectral represents from an remote sensed data into a classification ? Which classification is the most typical to use when doing that ? How many ...
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1answer
23 views

How to create my own remote sensing index?

Using Landsat images how do I create my own indices to extract particular landuse? Are there any tool/ software for creating indices?
5
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1answer
71 views

Why does Landsat 8 panchromatic band NOT include the infrared?

The panchromatic band on Landsat 8 OLI sensor (band 8) covers a narrower portion of the spectrum than the corresponding band in Landsat 7 ETM+: 0.50 - 0.68 micrometers (L8 OLI) in contrast to 0.52 - ...
2
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1answer
38 views

Obtaining free satellite imagery for Australian floods?

How can I obtain free satellite imagery for Australia? I want to find the extend of flood in specific time. I have already tried land-sat.But unfortunately there is no data available for that specific ...
3
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2answers
206 views

Why use feature extraction?

Why is feature extraction important? Why do we have to reduce the feature space? Is it only a computational problem when we use hyperspectral imagery or does this procedure improve the ...
1
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1answer
39 views

Feature extraction in remote sensing!

Which are the most common features in order to perform a supervised classification in remote sensing? Furthermore anyone worked with SAR features? Which are the most commonly used? Can anybody suggest ...
1
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0answers
29 views

Retrieving Aerosol Optical Depth (AOT) from Landsat multispectral data

I need to retrieve Aerosol Optical Depth from Landsat multispectral datasets. Has anyone successfully tried something like that before?
1
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3answers
112 views

Pixel-based and object-based classification!

I would like to understand if pixel-based classification algorithm (e.g. Maximum Likelihood classification ) can be used for object-based classification (i.e. after a segmentation procedure). On the ...
6
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2answers
133 views

what's the difference between spectral signature and features in remote sensing?

I would like to understand if is there any difference or relation between spectral signature concept and features in remote sensing?
0
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1answer
38 views

How convert a Modis hdf to txt with lat long using a command line

I need convert, from command line, an Modis hdf file to txt with lat/long extracting EVI. Thanks
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0answers
70 views

How to Normalize or rescale the NDVI raster image

I have processed my landsat band 3 and band 4 of different years to derive NDVI values the possible values of Normalized difference vegetation index is -1.0 to +1.0. The bands were atmospherically ...
0
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0answers
70 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 ...
2
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0answers
70 views

Python script for dark object subtraction on Landsat 8 Imagery

Does anyone know of any python scripts that will allow me to conduct such a process? I am limited to open source software and have minor experience in Python.
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0answers
7 views

How to avoid background zero values in erdas imagine model maker? [duplicate]

Does anyone know how to avoid background black color/ zero value in background pixels in processed images using erdas imagine? Particularly in model maker. It's confusing in statistical calculation.
1
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1answer
97 views

Workflow of Processing Landsat data for landcover classification

I have downloaded Landsat-8 data to make a land-use raster. So far I've made a composite image and clipped it by my study area. As you can see, there is some slight cloud cover. I've gone ahead and ...
1
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0answers
126 views

QGIS 2.4.0-Chugiak: How to threshold NDVI to calculate emissivity for land surface temperature

I am analysing urban heat island using thermal band 6 of landsat TM-5 sensor with respect to Normalized difference vegetation index that derived from the Band 3(Red) and Band 4(NIR). Lansat TM years ...
3
votes
1answer
86 views

Handling mountain shadows when classifying Landsat 8

I'm trying to classify some area in northern Mongolia using Landsat 8 satellite images from 2013. Since the recordings were made in winter, the sun is very low at the acquisition time. Therefore there ...
2
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1answer
23 views

Determine mudflats area from remote sensing images

I need to determine the mudflat area for a group of small islands in the Red Sea. I have read some publications and it seems to be possible using remote sensing, for example Landsat. But I am not ...
9
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1answer
293 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
42 views

How to derive the slope angle value from DEM?

I am trying to calculate the steepness of each pixels (30m) from the DEM of 2m resolution. I have made use of ERDAS Imagine - Slope function and returns a contour-like pixel image. The pixel value ...
3
votes
1answer
156 views

Download new SRTM 30 meters

I read about the new version of the digital elevation model at 30 meters (SRTM 30 meters), but I can not find from were I can download it. some sources: ...
3
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2answers
95 views

automatically geo- and ortho- rectify raw Landsat data using DEM

I have a dataset of 20 Landsat scenes (MSS, TM, ETM+) for 20 years (one scene per year). Scenes are in WGS 84, EPSG 32634 coordinate system and I can easily project = geometrically correct them to ...
2
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0answers
49 views

Possible to use same signature file to classify images from different years?

I have Landsat images for the same area over 20 years (one photo per year in same season). I would like to detect changes occured in forested area like clear-cut and bark beetle outbreak over time. I ...
2
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0answers
24 views

A problem about Correlated-K algorithm of MODTRAN 5

When I use MODTRAN 5.2.2 to run the test case 'CorrelatedK.tp5', I get the following warning information. How I can solve this issue? WARNING: The Correlated-k option was turned off. The ...
4
votes
2answers
101 views

How to filter LiDAR data by scan angle?

I am looking to filter LiDAR data (.las format) by scan angle specifications (e.g. keep all points < 15). From a basic Google search, it appears that the LibLAS library has the ability to filter by ...
3
votes
1answer
190 views

Calculating NDVI using Landsat ETM+ band values

I have sample points (shape file converted from a .xls file which contains XY coordinates,nnx,nny and canopy density) and a landsat etm+ image. First I applied 'SpatialAnalyst Tools>Extraction ...
1
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1answer
45 views

Maintaining spatial integrity of Matlab matrix with missing data

I am working with MODIS Terra imagery (MOD13Q1). I am currently trying to compute the autocorrelation structure of the pixels in an MODIS NDVI raster. The problem is that I have clipped the original ...
1
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1answer
35 views

how to perform PCA with 2 different landsat scene

I want to perform PCA on 2 sheets of Landsat imagery with different acquisition time and coordinates. prior to processing, should I combine both into one scene (mosaicking process)? if so, how is the ...
3
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0answers
48 views

At surface reflectance values

I have calculated at sensor reflectance for a multispectral image and preformed atmospheric correction. The reflectance values for the visible and NIR bands are between 0.2 to 0.01 for surface eg veg, ...
2
votes
1answer
78 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 ...
5
votes
3answers
214 views

How to generalize training data for a random forest classifier?

I am working with a random forest classifier in eCognition (new with eCognition 9.0). The image shows 8 NAIP tiles I am attempting to classify using approximately 100 training points. The training ...
4
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3answers
51 views

Residential tree cover for surveying?

Can someone point me in the direction of some high spatial resolution and reasonably recent satellite imagery for central Canada (Manitoba)? I am trying to determine whether I can generate accurate ...
3
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1answer
189 views

Panchromatic Image association with high spatial resolution

How and Why is a Panchromatic Satellite Image associated with high spatial resolution? I googled and found that it is a single band image, but then why is it called pan-chromatic(All Colors). Does it ...