Remote Sensing

Remote Sensing

  • Subhajit Bandopadhyay added an answer:
    What are the effects of grid resolution on data accuracy?

    For an example the city of New York.

    How will  layers grid resolution impact the ability to determine whether the city of New York has a higher temperature than the surrounding areas?

    Subhajit Bandopadhyay · Indian Space Research Organization

    I don't think so that grid will determine the accuracy of any datasets. Best to do make a grid for data processing rather than fixing the accuracy. 

  • José M.C. Pereira added an answer:
    Is it possible to access to geostationary satellite data?

    Hi every one. I need free geostationary data (TIR band) in a particular period (e.g. December 2003, ) . Is it possible to access to this data? Can anyone introduce any websites to access to them? Thank you for your help.

    José M.C. Pereira · University of Lisbon

    You may want to try the EUMETSAT Land Surface Analysis Satellite Applications Facility, http://landsaf.meteo.pt/

    Best wishes

  • Tomáš Brunclík added an answer:
    Landsat 8 atmospheric correction SW?
    Does there exist a software already able to do atmospheric correction of Landsat 8 imagery to ground reflectance, preferably a free?
    Tomáš Brunclík · University of Pardubice

    To return to the topic, I just have published new version of my atmospheric correction script.
    https://www.researchgate.net/publication/279031041_i.grid.correl.atcor_version_0.92b?ev=prf_pub
    Most imortantly it features orthogonal regression, which should work better than ordinary least squares for the type of data used. But I have to warn Windows users, the script does not work for me in WinGRASS. It may work for you, but most probably will not, as it seems to be caused by a problem in the Windows version of GRASS. Linux and Mac users should be fine.

  • André Beaudoin added an answer:
    Can anyone tell me that why L-band PALSAR data is suitable for fire monitoring?

    I am trying to search on of the publication of L. L. Bourgeau-Chavez, F. Siegert, E.S. Kasischke on L-band PALSAR data utilization for fire monitoring. Can anyone tell me that why L-band PALSAR data is suitable for fire monitoring?

    André Beaudoin · Natural Resources Canada

    Hello Tasmeen, this PALSAR-based change detection paper, though in boreal forests, could be of interest for mapping fires in your context:

  • Jack H Hiller added an answer:
    Anyone focused on precognition or intuition research possibly within human-computer interaction?

    Does anyone also measure difference between probability and higher success when humans are intuitively selecting right answer?

    Jack H Hiller · Retired

    Wrote paper for DoD on the important use of intuition in military decision-making as a driver for data base searches to verify and adjust "picture" of the battle-space (contact me for copy at jh7138@gmail.com).

    Also posted paper on Descartes' mind-brain dualism theory in which Near Death Experience (NDE) reports strongly support his theory and  reconceptualized space-time wherein time is a  real 4th dimension( http://www.nderf.org/NDERF/Articles/frozen_time.htm  ). Intuition is thus shown to have a potential source in mind, in contrast to brain functioning.

  • Simon J. Dixon added an answer:
    Where can I get free LIDAR data?

    Using LIDAR to model rainfall interception is advantageous to other interception models in many respects (e.g., Gash, Revised Gash, Rutter, and etc.). While published models on rainfall interception have shown to be highly accurate, most require many parameters and long-time measurements.
    To understand regional or watershed-level eco-hydrological processes, LIDAR can provide both the spatial coverage and resolution needed to address such questions.

    Simon J. Dixon · University of Birmingham

    If you can wait until September the Environment Agency in the UK is making all their lidar open data from then.

    http://www.gogeo.ac.uk/cgi-bin/resource.cgi?cat=2

    From memory they have 5m resolution for the whole of the UK and in selected places 1m.

  • Volkan Yilmaz added an answer:
    Satellite sensor that provides both PAN and MS image?

    MS is normally called as Multi spectral image and PAN is panchromatic image . What is the abbreviation of PAN. 

    Volkan Yilmaz · Karadeniz Technical University

    IKONOS, Quickbird, Geoeye, Hyperion, Landsat, Worldview, SPOT, Orbview are some of the sensors provide both multispectral and panchromatic bands.

  • Rebecca Lemons added an answer:
    Remote sensing data or images vs remotely sensed data or images. Are they both OK?

    I have used in the past both "remote sensing" and "remotely sensed" as qualifiers to refer to data acquired by airborne or spaceborne sensors. However,  I feel increasingly uneasy about "remotely sensed", because I find it convoluted and even a bit pedantic. I would like to convince co-authors to give up using "remotely sensed", and I offer two arguments:

    1. A digital picture of a lake taken  from the top of a mountain was indeed remotely sensed, but it's clearly not what we would understand as a remote sensing image.
    2. 'remotely sensed' is a secondary jargon derived from the primary jargon 'remote sensing'. Why should we use yet one more jargon when the original one can also work as an adjective?

    Can you come up with any other supporting argument, or if you prefer 'remotely sensed', can you come up with a counterargument?

    Rebecca Lemons · University of North Dakota

     They are the same thing. Generally what we see currently in the literature is that the terms are interchangeable. I have seen where old photographs were used to as remote sensed to create maps of historic vegetation. Additionally currently technologies such as those images taken in your phone have location data associated with them. So pictures from a camera and those taken via a satellite are not much different, only the angle of view. After all satellites are just fancy cameras that can pick up a broader spectrum than the visual bands that your hand held camera does.

  • Roger Lukas added an answer:
    Air-sea interactions during storm winds?
    Can you please suggest a recent experimental and theoretical articles on air-sea interactions during storm winds (more then 20 - 25 m/s)?
    Roger Lukas · University of Hawaiʻi at Mānoa

    Soloviev and Lukas: The near-Surface Layer of the Ocean (2014, 2nd edition, Springer). See Chapter 6.

  • João Arthur Pompeu Pavanelli added an answer:
    Which SAR data are freely available?

    In a soil moisture study, I need to have the spatial distribution of soil moisture in high resolution, to evaluate its relationship with topographic factors.

    João Arthur Pompeu Pavanelli · National Institute for Space Research, Brazil

    Alaska Facility had just opened PALSAR-1 archives, from 2006 to 2011. Enjoy it!

  • Dhananjay Sant added an answer:
    Can anyone explain landscape configuration and landscape composition and their importance in landscape ecological studies?

    Remote sensing ,landscape studies 

    Dhananjay Sant · The Maharaja Sayajirao University of Baroda

    Landscape is an assemblage of various landforms having different origin interns of processes and time. each landform therefore have different sediment sequence and thereby different thickness of soil profiles locally. Group of flora and fauna would have their preference in growth and occupancy. When one undertake ecological studies one needs to tie up characteristics of occupancy and habit of flora and fauna with landscape.

  • Reza Kahani added an answer:
    How can I deal with different number of pixels for Training data on Image Classification?

    In some studies, different numbers of pixels per class were used for training. Therefore, the training data are unbalanced. However, many studies have shown that unbalanced training sets do bias the results. Should we use equal number of pixel per class for training everytime on image classification? Any answer will be appreciated!

    Reza Kahani · Shahid Beheshti University

    Hi,
    if I've understood your problem correctly.
    Divide the images to equal parts, and then extract equal number of features (e.g. statistical features) from each parts, and finally concatenate all features, can be useful in some cases.

  • Mustafa Üstüner added an answer:
    How can I clean the scattered pixel (class/single pixel) in land cover map (Erdas/ArcGIS)?

    Hello everybody,

    After I did a classification map, there are existed a lot of scattered pixel (class) which no related with neighbor pixels (class). I tried to resolve this problem with Boundary Clean tool in ArcGIS (ArcToolbox--> Spatial Analyst Tools --> Generalization --> Boundary Clean). However, I think that the result is not really good, some wrong as well. Please read it on the "Before boundary clean 1" and "After Boundary clean 1" photos that I enclosed in this question.  How could I clear up this case?

    Thank you in advandce!

    Nguyen

    Mustafa Üstüner · Yildiz Technical University

    ENVI....Majority/Minority Analysis....

  • Surajit Panda added an answer:
    How can I choose, the peak value in the calculation of PSNR where the pixel values range from -1.0 to 1.0 for MODIS images?

    It is not clearly mentioned as to consider the peak value or the range in most internet sources. In my case peak becomes 1 and range is 2. What should I go with?

    Surajit Panda · Jharkhand Space Application Centre

    By using band math function of ENVI softwere

  • Masoud Minaei added an answer:
    Which is the best classification algorithm for quantifying urban LULC using Landsat images and kindly specify the reason?

    Remote Sensing, Urban, LULC

    Masoud Minaei · University of Vienna

    Dear Krishna

    Thanks for your answer.

    regards 

  • Diogenes Salas Alves added an answer:
    Is there any open source software for runoff calculations?
    I want to calculate runoff accurately where rainfall data is given as an input.
    Diogenes Salas Alves · National Institute for Space Research, Brazil

    You can also try SWAT. The current (Vol 60, Issue 5) of the Hidrological Sciences Journal presents a number of related papers:

    http://www.tandfonline.com/toc/thsj20/current

  • Husam El Alqamy added an answer:
    How I can Extract Shoreline from Landsat image using ERDAS Imagine?
    Which Model in ERDAS can help me to digital extraction of coastline?
    Husam El Alqamy · Environment Agency - Abu Dhabi

    would  the outcome of the MNDWI get affected by the water depth. In other words, any ideas about how deep the water should be to be picked by MNDWI and not missed for the underlying terrain which may have some reflectance. 

  • Majid Hojati added an answer:
    What is Minimum Reflectance Technique in remote sensing?

    Hi,

    In my study I have to separate aerosols reflectance from surface reflectance.I have studied some articles and I have found that some techniques such as Dark target and MRT (Minimum Reflectance Technique) is used to get a surface reflectance that has least amount of aerosols effect,I searched but could not find any detailed information about MRT,I want to run this technique on MOD09 surface reflectance(At this stage I have not decided which temporal resolution (8days,1day or etc) to use) In case of getting a clear surface reflectance,

    Can you please give me some sources about this teqnique and also give me your opinions about this technique and it's accuracy?

    thank you so much

    Majid Hojati · University of Tehran

    There is also two manuals about DT and DB algorithms which gives quite good information about advantages and weaknesses of these algorithms 

  • Morteza Sadeghi added an answer:
    How can I get the soil moisture products freely online?
    Where can I get the soil moisture products feely online? I'v been confused by the question for a long time. It will be very kind of you who can provide me some useful information about soil moisture data derived from remote sensing .
    Morteza Sadeghi · Utah State University

    Hi,

    If you want to use optical satellites (e.g. Landsat, MODIS) you may use our newly developed model which is a simple linear relationship between a transformed reflectance at SWIR (band 7 of Landsat and MODIS) and surface soil moisture:

    https://www.researchgate.net/publication/275026226_A_Linear_Physically-Based_Model_for_Remote_Sensing_of_Soil_Moisture_using_Short_Wave_Infrared_Bands

    In the following note, we describe how you can find the soil parameters without any need to ground measurements:

    https://www.researchgate.net/publication/275659087_A_Calibrationless_Method_for_Optical_Remote_Sensing_of_Surface_Soil_Moisture

    Hope it will help,

    Morteza

  • Giovanni Pecora added an answer:
    Comparing images acquired by different satellites?
    I am doing land use change detection based on landsat 5, 7 and 8 images. At the pre-processing step I have done radiometric calibration and also used dark-object subtraction technique for all scenes. The changes of the three time points based on landsat 7 offer reasonable trend as desired (forest decline). But the result of the landsat 8 image shows a sudden increase of forest area, whereas the results of landsat 5 show the minimum amount of forest area. I do not know what is wrong! Should I have considered something special when comparing images from these different satellites?
    Giovanni Pecora · Università degli Studi della Basilicata

     Thanks a lot Pat, I'll see your pubblications very soon ;-). Thanks again

  • Francesco Bianconi added an answer:
    What are the main criteria to select frequency scales and orientations in 2-D gabor filtering for images?

    I want to extract texture features from images using 2-d gabor filtering. What are the way to choose frequency range and how many scale i should use. 

    .

    Francesco Bianconi · Università degli Studi di Perugia

    Hi Prem,

    Here's a paper you might find useful:

    Bianconi, F., Fernández, A. Evaluation of the effects of Gabor filter parameters on texture classification (2007) Pattern Recognition, 40 (12), pp. 3325-3335.

    Apologies for citing my own work ;-)

    Best,

    f.

  • Mohamed Barakat Abdelfatah added an answer:
    What are the parameters that need to be taken into account in order to detect roofing material degradation status from WV-2 or WV-3 satellite imagery?

    The use of very high-resolution satellite images such as WV-2 and WV-3 to map urban areas will lead to revealing more complex detailed, and an enormous amount of information can be extracted if OBIA approach is used. Several studied can be found in the literature that used VHR images for urban mapping, but is it possible to go into intra-class level and differentiate between the deterioration status of some roofing materials?. If that possible what will be the factors that can be taken into consideration in order to reveal these subtle differences?

    Mohamed Barakat Abdelfatah · Putra University, Malaysia

    Thank you very much dear, Norman for the informative answer  :)

  • Mohammad Abdel-Razek added an answer:
    How can I extract seasonal metrics from NDVI time series by using R?

    I need to extract NDVI phenological parameters on pixel-basis according to the paper of Reed et al. (1994) "Measuring phenological variability from satellite imagery".

    I refer to the TIMESAT program developed by Jonsson & Eklundh and published in Computers & Geosciences (2004). It only works in matlab-like environment... Thanks!

    Mohammad Abdel-Razek · University of Bonn

    As Jan pointed, MODIS package is very useful in data preprorcessing. May be phenex package (auxiliary functions for phenological data analysis) is useful in extraction of the parameters you are looking for:

    http://cran.r-project.org/web/packages/phenex/index.html

    Cheers, Mohammad

  • Sainath Aher added an answer:
    How do I generate DEM using cartosat stereo pair?

    I am trying to generate DEM from cartosat stereo pair. With the help of point measurement tool I have entered the control points and when I perform the auto tie point generation, I received a popup message. The RMSE error was high(0.6). does this pop up message has any relevance in getting high RMSE error? Can anybody suggest how to over come with this pop up message.

  • Mokhtari djamel eddine added an answer:
    Georeferencing in ERDAS via Google Earth
    is it possible to georeference MODIS image in ERDAS IMAGINE by using Google Earth as reference image (to select the GCPs)?
    Mokhtari djamel eddine · Hassiba Benbouali Chlef university, Algeria

    Try with

     https://www.youtube.com/watch?v=sCtmT0DisVY

    For Linking ERDAS Imagine to Google Earth
     


    And in Erdas 2013 for Synchronise Erdas with Google Earth
    https://www.youtube.com/watch?v=zanHaeJSV5s

  • Camilla Agostini added an answer:
    How can tablets be most effectively used in archaeological excavation?

    I am planning an excavation project and I am considering putting all field data recording on tablets. I am looking for articles discussing the use of tablets in the field to keep notes, fill in forms, take photographs and make maps. I would also appreciate advice on what tablets to use and the best software for different tasks.

    Camilla Agostini · Universidade Federal Fluminense

    I have just concluded an article that points this use in a very simple but, I believe, in a very useful way. The text is in Portuguese, thou..  

    Anyway, I´ve been using it not much as a quantitative file, but for a variety of qualitative recordings, including the use of small videos about technical information of the excavation process, interviews or spontaneous conversation with the public, ethnographical recordings associated with archaeological field work, etc.

    At the end, this constitutes a database as an usual photo database of fieldwork. But the qualities of the image and the potential information of the video make it a very useful and interesting material. For technical analyses and doubts that emerge in the Lab, or even for the future production of documentaries or public material.

    Example of this last use in the video edition in http://conversadehistoriadoras.com/page/5/  post of July 21 2014 

  • Frank Veroustraete added an answer:
    How can I detect desertification by remote sensing?
    Which image product is best suited for this purpose and how can I download that product?
    Frank Veroustraete · University of Antwerp

    Hi Behrooz,

    I made a study of desertification in the Xinjiang province (North- Western China) lately, using a  multi-temporal series of 50 years Corona and Landsat imagery. The LUCC is enormous over that time lapse in the Xinjiang province. It led to increased desertification in originally natural landscapes. In short, an originally natural landscape  with gallery forests along the Tarim river and its tributaries changed into a patchy landscape with irrigated agriculture plots on the one hand and sandy deserts on the other hand. This LUCC had a fundamntal impact on regional hydrology. The Tarim river in the 50 years mentioned retracted by more than 200 km from its original Gobi desert ending.  If you want to know more, then read the paper available on ResearchGate:

    https://www.researchgate.net/publication/235959317_Diachronic_Mapping_of_LUCC_in_the_Northwest_of_China_over_the_last_half_Century_Conversion_of_CORONA_Panchromatic_reflectance_into_LANDSAT_NDVI_Imagery

    I think that the Xinjiang province gives a fairly good example of what large scale desertification is all about e.g., humans changing natural landscapes - in equilibrium with regional hydrology - replaced by desert and irrigated cropland (mainly cotton for export to SoutWestern China sweatshops). In fact the original water resources in the new landscape has been focussed on irrigated agriculture and the original natural landscape  degraded into sandy desert. Another large scale example exists in Kazakhstan (Aral Sea), not that far Norrth from the Xinjiang province, with the difference that the Aral Sea has almost vanished into pure desert. Al fishing activities in the Aral Sea have stopped and people had to move or die.

    Cheers,

    Frank

  • Natalia Zazulie added an answer:
    Can anyone recommend a threshold for Landsat 8 band ratio to delineate glacier areas?

    I am using Landsat images. For Landsat 4, 5 and 7 I have been using the band ratio TM 4/5 with a 3.3 threshold to identify snow/ice pixels. Can anyone recommend a threshold for band ratio 5/6 for OLI-TIRS sensor to distinguish snow/ice surfaces? Or does anybody know any article working with band ratios in Landsat 8 for glacier identification?

    Natalia Zazulie · University of Buenos Aires

    Thank you Onur Satir

  • Bekk Okk added an answer:
    Is there any software to process airborne SAR data?

    I want to gain DOM based on the data of  airborne SAR data and DEM

    Bekk Okk · Abou Bakr Belkaid University of Tlemcen

    there is a matlab code function with comment:

    %This function implements basic range-Doppler algorithm to focus a
    % single-look-complex (SLC) image out of airborne SAR RAW data.

    if it does what y want  this is the link:

  • Peter Friedl added an answer:
    How can I enable multithreading for GAMMA remote sensing software algorithms?

    I am currently working on an HPC-Cluster with 16 available threads. So I put the command export OMP_NUM_THREADS=16 at the top of my bash script, hoping that the number of threads is set for all following GAMMA-functions that use OPENMP. Unfortunately this is not working (e.g. with running offset_pwr), as still the default number of 4 threads is used. Does anybody have any suggestions?

    Peter Friedl · German Aerospace Center (DLR)

    Short update on multithreading for GAMMA`s offset_pwr, offset_pwr_tracking, offset_pwr_trackingm and offset_pwrm functions: New versions (May 2015) of these programs are available which now allow multithreading. As some of you probably observed, the older functions in the version of Dec. 2014 do not allow multithreading and additionally have severe problems with tracking accuracy. The latter is obviously caused by wrong SNR estimations made by the programs. If you need the new versions of these algorithms, you can write to GAMMA and they will send them to you via Email.

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