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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3
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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 ...
7
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0answers
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 ...
4
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0answers
73 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 ...
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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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, ...
3
votes
0answers
46 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
votes
0answers
111 views

Pan sharpen Landsat 8 using Grass 7

I have followed this great tutorial on pan sharpening using Grass GIS 7 (I'm using beta 3). Everything in the tutorial seemed to have worked, but my final output is not as expected (pictured below). ...
3
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0answers
69 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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0answers
92 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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0answers
185 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
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.
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 ...
2
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0answers
23 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
votes
0answers
61 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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0answers
52 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
40 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
40 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
166 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
412 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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0answers
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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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 ...
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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 ...
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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?
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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 ...
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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 ...
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0answers
64 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 ...
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0answers
44 views

Urban Heat Island USING ENVI

I have downloaded MODIS images for a specified area.. Its my first time that I am working on UHI (Urban Heat Island).. I need to know the methods to work on it.. I am using ENVI for this.
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0answers
156 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 ...
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0answers
26 views

How to create Strips with GCP point distribution for raw GeoEye satellite imagery?

I have raw GeoEye satellite imagery, I just want some guidelines for creating a strip map with GCP distribution. We need to make orthorectification for raw GeoEye satellite imagery, I think it's ...
1
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0answers
29 views

Water grey levels - remote sensing

by viewing two bands in erdas imagine the grey levels of the water differ. on the one image as below the water is dark and the other image the water is light. why is that? what cause the ...
1
vote
0answers
22 views

Determine sun elevation without header file?

I have some AWiFS and LISS-III data that I'm trying to convert from at-sensor spectral radiance to top-of-atmosphere reflectance. The problem is, the data didn't come with any header file. All I ...
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0answers
146 views

problem of using TIMESAT to processing MODIS NDVI

I want to use TIMESAT software to analyse time series MODIS NDVI data. Firstly, I use MRT tool to mosaic,subset and project MODIS NDVI data and output data as GEOTIFF format, and save as ENVI standard ...
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0answers
55 views

How to select MODIS pixels with 80% homogeneous landcover from landsat classification?

I have a complex landcover classification for a landsat scene at 30m spatial resolution. Includes about 600 land cover classes. There is a fair amount of clumping per group. I have a MODIS EVI 16 day ...
1
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0answers
57 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
0answers
57 views

Distinguish between the types of cultivated crops in remote sensing

I recently produced map of LULC but there is the difficulty of distinguishing between the types of crops. Is there a method to distinguish between the types of cultivated crops such as wheat, barley, ...
1
vote
0answers
90 views

Importing GPS coordinates to extract multiple DN values in ERDAS

I have a set of GPS points (stored as a csv for now) and would like to import these points to ERDAS to find the DN values associated with each location. I am able to import a SHP to ERDAS but the ...
1
vote
0answers
166 views

Change Detection ArcGIS with multiple dates

I'll explain my aim first: I am trying to create a single raster to represent vegetation resilience, I am doing this via change detection. So far I have created 5 Change detection images, where 2000 ...
1
vote
0answers
310 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 ...
1
vote
0answers
114 views

How to convert MODIS (Vegetation Continuous Fields - MOD44B) to (.img and hdr) in ENVI

Please can anyone help me to convert MODIS (Vegetation Continuous Fields) to (.img and hdr) formats? In ENVI, anytime i try using the MODIS conversion toolkit, a dialog box appears telling me to ...
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vote
0answers
212 views

How to mask clouds in ER Mapper?

I am using ER Mapper. But, I'm still confused how to detect and mask the clouds. I want to reduce or eliminate the cloud to perform supervised and unsupervised classification.
1
vote
0answers
183 views

Averaging satellite data with missing values (using Python)

I am using sea surface temperature, chlorophyll, and other data parameters as covariants in a model, and I would like to average them over a particular time period. I am currently doing this using a ...
0
votes
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 ...
0
votes
0answers
18 views

Urban heat island

Since there are lots of products in MODIs for Urban heat Island can anyone suggest me which is the best one?and why?I need to start working on Urban heat Island of some city in Asia but before that I ...
0
votes
0answers
17 views

How to compile the source code of module MOD14 of NASA

I'm working in a project which uses an Active Fire Detection base on MODIS (MOD14) of NASA. The source code and compiled-file can be downloaded at NASA Now I want to compile the source code, ...
0
votes
0answers
84 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?
0
votes
0answers
68 views

Opticks 4.11.0 (Ubuntu 64bit) - unable to load TIFF file

I am trying Opticks 4.11.0-1 - have official release opticks_4.11.0-1_amd64.deb but unlike in Windows I am totally unable to load Landsat 7 TIFF files. In Windows I can do this using auto importer. In ...
0
votes
0answers
66 views

Masked data included in ISODATA classification computations?

I am using ENVI to mask NDVI MOD13Q1 images using the "pixel_reliability" raster included in the MOD13Q1 hdf. All instances of cloud cover (pixel_reliability=3) have been masked (=0). I have applied ...
0
votes
0answers
234 views

Atmospheric correction for RapideEye without atmospheric parameters

I'd like to perform an atmospheric correction of my RapidEye images but metadata do no include atmospheric parameters required to use the 6s algo implemented in the Orfeo ToolBox. Is there a solution ...
0
votes
0answers
46 views

patch analysis and spatial statistics for Grid data

I have TerraSAR data (raster data) for settlement, I must show the large density building, medium and low density in the map. Is this possible in the spatial analysis or patch analysis? I look ...