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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5
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88 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, ...
5
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207 views

Multispectral image segmentation for natural-resources applications using R

R has the capacity for image segmentation, although all of the examples I have come across utilize a single band for the segmentation (example). I am interested in combining R's capacity for random ...
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168 views

Which remote sensing satellite is best used for chlorophyll mapping?

Location of my research are reservoirs which have an area of 47 and 62 km2. I need a better image resolution than Landsat(Pan).
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91 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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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 ...
3
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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 ...
3
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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 ...
3
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332 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
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52 views

How to detect temporal changes using ArcGIS?

I want to show urban sprawl in a city over ten year period. I took a MOOC on geospatial revolution, therein a link was shared to do such analysis. I just want to show the urban sprawl, nothing ...
3
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93 views

Thermal Map Data

I am curious about making a thermal map to display where the hot spots and where the cool spots in a community are. Obviously the roads will be hot and the shaded areas with trees will be cool but ...
3
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109 views

Using Quickbird to discriminate vegetation response and spectral signatures - which season?

I have a study area in N. Florida loblolly pine plantation with 3 treatments (drought, fertilization, drought+fertilization, control) and 4 replicate plots. All plots will be in the same scene. These ...
3
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217 views

How to merge SeaWiFS and MODIS data or use other merged products?

I hope to produce a time-series for sea surface temperature (SST) and chlorophyll-a (Chl-a) for use in MaxEnt without the use of arcgis, preferring Python tools to others. I am new to satellite data ...
2
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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
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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 ...
2
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0answers
81 views

Landsat TM, ETM+: what are radiometric calibration coefficient of each sensor to convert DN to radiance

The Landsat TM Image data that comes with zipped folder contains metadata text file in which all necessary information have been written. In order to further process that data, first DN to radiance ...
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224 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.
2
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0answers
34 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 ...
2
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0answers
73 views

ASTER mineral indices with VINR and SWIR data

I need to run a supervised classification on ASTER data in order to map a rock formation, which is composed of chert. There is no shortage of indices which can be used to highlight silica rich ...
2
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103 views

R: Can raster predict function pass to predict.rfsrc (a prediction function in a parallel verion of RandomForest)?

It seems that raster predict function can pass to predict.randomForest by setting the "type='response'". I am using a parallel version of randomForest package called the "randomForestSRC" and I am ...
2
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72 views

How is Canada Vector Data (CanVec) hydrology data collected and updated?

Canada is vast and collecting any geographic data must be a monumental task. Natural Resources Canada provides a free access to a comprehensive Canada-wide topographic data now refereed to as CanVec ...
2
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0answers
42 views

differentiating stone houses from barren rock in ArcGIS 9.3

I'm working in ArcGIS 9.3 trying to differentiate stone houses (often red brick roofs) from barren rock in a typical Mediterranean karst region via remote sensing. I have been using Landsat imagery. I ...
2
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0answers
44 views

“Back calculating” to quantify the “atmospheric effect” of water vapor or other gases in a “corrected” hyperspectral image using QUAC?

I know that when using FLAASH in ENVI, you can produce a water vapor map (caveats considered) from your atmospheric correction. My question is if it is possible to "back-calculate" a water vapor map ...
2
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0answers
447 views

Question related with NDVI value on water

There is a surreal thing on my NDVI images. NDVI values on lake is ranging from -0.04 to 0.7. (The lake surrounded by forest and has freshwater). Theoretically, negative value of NDVI is correspond to ...
2
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0answers
206 views

ENVISAT ASAR .N1 file is not being opened by ERDAS IMAGINE 2011

I am not able to open ENVISAT ASAR .N1 file in ERDAS IMAGINE 2011. The software has direct read option for files of this format. Whenever I try to open the file, software closes automatically giving ...
2
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0answers
539 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 .
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27 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 ...
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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 ...
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0answers
52 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 ...
1
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0answers
37 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 ...
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0answers
50 views

SRTM DEM and satellite DEM fusion

I have a SRTM DEM and a DEM derived from satellite (Cartosat). Both the DEMs are registered perfectly. Now I want to carry out a DEM 'fusion' process to derive a higher quality output DEM. I am not ...
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0answers
21 views

LULC using SAR data

I have a Geocoded SAR data with me. I have to perform LULC classification. I have been given a shapefile (vector data) with the different LULC categories of the region. The region is mainly composed ...
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0answers
44 views

Effects of heterogeneous vegetation in mapping canopy cover using randomForest in R

I have a 5.8 m resolution satellite image (LISS IV by IRS-P6, in bands 4, 3 and 2) of a densely forested region in the Eastern Himalayas. My objective is to predict regions of canopy cover. Regions of ...
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0answers
21 views

Cloud and cloud shadow identification with MERIS

I am looking at MERIS images to use for marine applications (Chl-a. SPM) and would like to confidently remove cloud and cloud shadow pixels from the data. I have a few ideas: Using the blue band ...
1
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0answers
32 views

Using NDVI values as covariate in survival analyses

I am trying to become more familiar with processing NDVI values in GIS. However, despite its usefulness, it seems to have some limitations. Namely, creating NDVI values across a large scale can be ...
1
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0answers
42 views

Extract Differential Interferometry from SENTINEL-1 image

I downloaded some SLC images from scihub.esa.int . And I want to extract Differencial Interferometry from them by using SNAP-ESA software ( if you have other softwares that can do the same work I ...
1
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0answers
29 views

Modis Daily LST Data is mean of all day or it is on satellite path time?

I am looking for MODIS LST product which is exactly on the same time that satellite paths from a location,I have searched and found MOD11A1 but It seems that it is mean LST of Day,Is there any product ...
1
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0answers
51 views

Layer Stacking landsat 5 surface reflectance high level data

I downloaded the surface reflectance landsat 5 scenes but when I layer stacked them my image was not how I imagined. I manually used atcor on normal scenes and it looks nothing like the scenes I layer ...
1
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0answers
44 views

Landsat Data to Map Slums in India

I am working on a project to answer the following geographic question: How much have slum areas increased in Mumbai, India, since the 1970's (or earliest data). I have downloaded LandSat imagery and ...
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0answers
15 views

How to classify land cover with MMU 25hac

By using the 30 meter resolution of landsat TM & ETM+ data, I want to create the land use/ land cover map. I have read in several studies to first decide about the minimum mapping unit (MMU) that ...
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0answers
101 views

Landsat 7 band 6 VCID 1 (LOW) or VCID 2 (HIGH) for temperature map?

I want create water temperature map with Landsat 7 on QGIS. Band 6 converting to temperature, I read the landsat handbook with formula: T= K2/ (ln((K1/L)-1)). Band 6 has VCID1 "low" and VCID2 "high" - ...
1
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0answers
15 views

Hyperspectral Image + Field Data

There is plenty of remote sensing datasets out there, but I haven't been able to find one along with field data. Particularly I am looking for airborne hyperspectral images that have field data ...
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0answers
97 views

Format of raw LiDAR data (ToF data)

I am doing a project where I need to simulate LIDAR data, and I am looking for specifications on how raw LIDAR data looks. I want the format of the data before it is translated to x,y,z coordinates ...
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0answers
63 views

Are there any good MOOCs (online training courses) for remote sensing?

I'm looking for a MOOC (Massive Open Online Course) for remote sensing. Does anyone know if there is currently running or if is there any change to begin in the future any MOOC for remote sensing?
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0answers
18 views

What are the advanced fusion techniques for fusing 3 band multispectral and 242 band hyperion hyperspectral dataset?

I have used some of the image sharpening techniques such as Wavelet, Gram-schmidt, Principal component, Brovey. Other than this what are the new and advanced fusion techniques and in which software it ...
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0answers
58 views

ENVI: Postclassification, remove pixels of certain size

I did a classification over multiple Landsat imagery in ENVI 5.1, which turned out not too bad (ice and snow in Cyan in the picture below). Now I am about to do a postclassification to filter out ...
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0answers
232 views

How to create model maker NDBI indice using Landsat 8?

I'm having trouble making the model for NDBI (custom made in ERDAS 9.2) using Landsat 8 image? As a result of running the model I'm getting a white image.
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128 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 ...
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0answers
119 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?
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0answers
174 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 ...
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0answers
123 views

Batch GDAL_Calc multiple band calculation

I have a question concerning gdal_calc. I´m running windows 7 64b and am working from the OSGeo4W shell. I have multispectral images that need to be prepared for analysis but they are not saved in a ...