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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9
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0answers
411 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 ...
6
votes
0answers
216 views

Frontal Detection of sst & Chlorophyll image

I am working on sea surface temperature satellite images and looking for delineating gradients in open source on the basis of temperature. Is there any tool like Cayula and Cornillon front detection ...
5
votes
0answers
121 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 ...
5
votes
0answers
505 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 ...
4
votes
0answers
71 views

Counting number of plants in area using images from UAV?

How do I count the number of pineapple plants in a 1-hectare block? I have heard of these algorithms but I don't know how to do it. I'm still a newbie of QGIS, ArcGIS and ENVI. I have the NIR, RGB, ...
3
votes
0answers
46 views

Using original Landsat multispectral image or pan-sharpened image in land cover classification?

I am currently creating land cover maps of a number of national parks across Asia from Landsat 8 imagery and also later from SPOT imagery. I plan to use supervised classifications in ERDAS IMAGINE and ...
3
votes
0answers
147 views

Import GPS SINEX (for velocity analysis) into Sarscape or processing with others software

I try to import GPS snx. into Sarscape 5.2 (use GPS Import tool) and getting error 115) ) gps_type : [sinex] 116) ) generate_kml : [OK] 117) ) generate_shape : [OK] 118) ) ...
3
votes
0answers
29 views

Guide to aerial or space data types and availability

I am overwhelmed by the variety of types of satellite and aerial data (images?) available online. For example, at the USGS Earth Explorer data page, I see AVHRR; CEOS;Ikonos and OrbView; EO-1; GLS; ...
3
votes
0answers
22 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
votes
0answers
103 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
votes
0answers
337 views

Single Tree detection

I was wondering how I could extract "crown area" of single trees in a forest from a high-resolution image with only 3 band (RGB) in ArcMap. ( No NIR to use NDVI as any threshold). I need a fast ...
3
votes
0answers
69 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
110 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
votes
0answers
81 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 ...
3
votes
0answers
112 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
votes
0answers
236 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
votes
0answers
32 views

How to determine Visibility Map for Atmospheric Correction

As per Grass wiki: https://grasswiki.osgeo.org/wiki/Atmospheric_correction the atmospheric correction could be done using a visibility raster in conjunction with an elevation raster. With regards to ...
2
votes
0answers
33 views

TIMESAT seasonality data (MODIS EVI)

I am trying to get seasonality parameters from MODIS EVI (MOD13Q1) for Indonesia. I have loaded data from 2013-2015, but the plotted time-series is shifted from what I expect. Indonesia has ...
2
votes
0answers
52 views

16-day-MODIS NDVI values seem to be wrong compared to my soil moisture ground data!

I'm using MOD13Q1 product of MODIS for estimation soil moisture. As I know, this product is made up of the maximum value of NDVI of each pixel over 16-day calculated NDVI values. The problem is that ...
2
votes
0answers
70 views

Calculating Aerosol optical thickness from Landsat 7

EDIT I have added question down I am reading one paper and I found method to retrive AOT from landsat 7 image This should be simplifield equation, because they assumed observation zenit as 0. Than ...
2
votes
0answers
65 views

GIS or Remote Sensing technique to map sub-surface features?

I am trying to delineate agriculture tile drainage in Midwest. Does anyone know of any GIS and/or sub-surface remote sensing techniques to detect tiles/objects buried in shallow depth of soil? Does ...
2
votes
0answers
45 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
0answers
46 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 ...
2
votes
0answers
60 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
votes
0answers
120 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 ...
2
votes
0answers
322 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 ...
2
votes
0answers
360 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
votes
0answers
44 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
votes
0answers
100 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
136 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
votes
0answers
44 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
votes
0answers
49 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
votes
0answers
606 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
votes
0answers
237 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
votes
0answers
649 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 .
1
vote
0answers
34 views

salt marsh recession mapping with landsat/WV, IKONOS)

I am trying to detect timing and pattern of change in a particular salt marsh (low marsh sitting close to a high marsh). Basically, I'm interested in detecting changes in the leading edge for ...
1
vote
0answers
15 views

Difference between radiometric correction at surface and at sensor in ENVI

I want to ask you about the difference between the radiometric correction at surface and at sensor in ENVI software, I do the two in flash and radiometric correction and the results was same image. ...
1
vote
0answers
41 views

How to mosaic multiple MODIS images of Multiple months using MRT tool?

I have monthly MODIS images for 2001-2014. For few images mosaicing with reprojection can be done using MRT tool. However, for large number of images it's a cumbersome process. There are multiple ...
1
vote
0answers
26 views

qgis Semi automatic classification pluggin how to add text to rows in attribute table

I want to use a previously created shapefile as Training shapefile in the semi automatic cassification pluggin. Therefore i added 4 fields to this shapefile: Macro_ID (int), MCl_info (text), Class_ID ...
1
vote
0answers
38 views

How to extact very narrow water linear features from GeoEye-1 image

I need to extract beaver channels from a GeoEye image (attached image). What is the best approach to automatically delineate such very narrow and not very sharp water features?
1
vote
0answers
80 views

Format of SAR images

What is the format in which SAR images are stored? By format I mean when a SAR captures an image, it gets saved in what format? jpg? png? tiff? or there is some other special format? Is there a ...
1
vote
0answers
48 views

Hard wood tree and Soft wood(shrubs) Vegetation Differentiaton

How I Differentiate Hard wood tree (like Mango, Sal) and Soft wood(shrubs like reed) Vegetation using Multispectral or Hyperspectral Image? I have TM, ETM, OLI, Hyperion, Aster Image and ERDAS 2011, ...
1
vote
0answers
64 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 ...
1
vote
0answers
85 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
vote
0answers
151 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 ...
1
vote
0answers
37 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 ...
1
vote
0answers
68 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 ...
1
vote
0answers
38 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
vote
0answers
40 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
vote
0answers
52 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 ...