- Munthali Mg added an answer:15How to detect LULC changes using ArcGIS?
I am PhD student at University of Pretoria. Could you please assist me with tutorials for analyzing LULC changes for my study area using ArcGIS? I do not have basic knowledge for GIS and Remote Sensing. Please email the tutorials to firstname.lastname@example.org
Thanks Hein Van GilsFollowing
- Lucien Wald added an answer:19How can I find clear sky days in a year using meteorological measurements, primarily using GHI (Global Horizontal Irradiance) measurements?
Please suggest clear sky models/techniques/formulas which can be employed using a dataset containing the following given meteorological measurements to identify clear sky days in a year.
- Daily Global Solar Radiation (GHI) : Avg,Max,Min
- Daily Extraterrestrial Solar Radiation : Avg
- Daily Air Temperature : Avg, Max, Min
- Daily Relative Humidity : Avg, Max, Min
- Daily Sunshine Duration : Avg, Max
- Daily Wind Speed : Avg, Max, Min
I intend to implement the suggested equations/formulas/models in matlab.
Your problem does not have accurate solution even if you have set up a precise definition of what is a clear-sky because your data is not sufficiently resolved in time. I backup the answer of Chris Gueymard and Frank Vignola on the use of a model predicting the irradiation under cloudfree sky, a so-called clear-sky model
As written by my colleagues, such models need inputs that you may not have though they are likely available. Given your objective, you may find an interest to use the McClear service available at http://www.soda-pro.com/web-services/radiation/mcclear.
It is a service covering the world that delivers time series of irradiation that would be observed in a specific site under clear sky conditions, with a time step ranging from 1 min to 1 month. The Global, Direct and Diffuse Horizontal Irradiation, as well as the Beam Normal Irradiation are provided. The data are available from Jan. 2004 up to current day-2. Inputs about atmosphere properties are taken automatically from the MACC (now CAMS) database. MACC: Monitoring Atmosphere Composition and Climate, a series of European-funded projects. CAMS: Copernicus Atmosphere Monitoring Service, an operational program to deliver info and data on several properties of the atmosphere (mostly aerosols and gases) and other data, among which solar irradiation at surface.
Access to data is free and unlimited provided you have registered. You may also be interested in knowing that this service obeys the Web Processing Standard of the OGC and that you may call it automatically (after registration). Help may be found at http://www.soda-pro.com/help/macc-rad/automatic-access.
Details on the model may be found at http://www.atmos-meas-tech.net/6/2403/2013/amt-6-2403-2013.htmlFollowing
- Jorge A. Valdivia added an answer:4Is there any way to retrieve LAI (leaf area index) directly from Landsat 8 images?
I'm using ENVI 5.3 to do the processing, but if you know how to do this from any open source GIS software it's also valid :-).
I read an article that mixes both Modis MOD15A2 (LAI product) with Landsat 7 (ETM+) or Landsat 5 (TM) [Gao, F et al., 2012 ], but it is not what I'm looking for. I just want to use L8 images. If you know any way to do this or know any articles that could be usefull for this I'd be really grateful if you could share it.
The truth is that I'm trying to find an "easier way" to retrieve LAI in comparison to the mix of Landsat with MOD15A2, this is due to the fact that I really need to do a lot more things besides from retrieving LAI for my thesis. So any "easier" way would be much appreciated. Thanks in advance.
I have not retrieve LAI yet. I'm "preparing" everything before field working. My work involves field sampling and lab work to retrieve live fuel moisture content and other things. But you are right, I think that the best thing would be to do the regression with some VI's and see which one has the best fit.
My question was more focused on getting the "state of the art" about it :-)
I'll definitely go for the regression, and I think I'll be comparing those results with MOD15A2 LAI products.
Thank you for your answers, Thomas!
- Esther Mosase added an answer:6How to download EVI (out of Surface reflectance (SR) product) of Landsat 7 ?
I have explored Earthexplorer to download Landsat 7 surface reflectance (SR) products, where i get the option of Spectral indices (EVI, i chose), the downloaded data (rar file) has band-wise data and others, but NO direct EVI product... (Although it can be calculated from bands in ENVI)
Can anyone make me clear but that how they distribute that SR data.?
For direct download of Landsat level 1 EVI product already derived for you and other products you can use ESPA Bulk order. The link is provided here: http://espa.cr.usgs.gov/ordering/new, But before downloading or odering data you have to provide the scenes you are interested in in a text file, so you can use earth explorer or glovis to identify the scenes you are interested in.
I hope this helpsFollowing
- Joen Ren asked a question:NewWho knows the relationship betweeen water vapor flux (kg/(m2.s)) and water vapor content (mm)?
I need to verify output data (upward moisture flux at the surface) of WRF model by comparing with remote sensing data (water vapor content). But I don't know their relationship. Further more, who can provide me some advices about verification or valid data (high resolution both in time and space).Following
- Atiqa Khan added an answer:8How to calculate EVI from landsat 7 surface reflectance products?
I have downloaded Landsat 7 surface reflectance products, How to use that in the calculation of EVI? and What should be the range of values in output
@ Cole, by scale factor, what you actually mean? Kindly explain a little bit.Following
- Isa D. Kwabe added an answer:13What is the most appropriate remote sensing resource (sensor, resolution and classification system to use for mapping Nigerian mangroves ?
I am doing a research on Nigerian mangrove degradation in the oil producing Niger Delta. Your response will make for useful input in this syudy
Hello Dr Hein, apologies for late acknowledgement. Thank you for the resource.
- Фык Михаил added an answer:1How can remotely sensed catfish generate histopathology data to an i-phone?
histology data of gills and liver shall be carried out remotely and manually
Look at the options for constructing and SCADA real-time systems. Such hardware and software myriad versions.Following
- Xudong Zhang added an answer:4In addition to MODIS products, which satellite ocean color data is free and available now?
If you know, please introduce its/their websites?
what about GOCI? Maybe it will be helpful.
- Sigit Sutikno added an answer:16Can anyone help for 2D Flood modeling?I want to do 2D flood modeling for urban area of 500 km2 and River length 20 km (submerge area and flood depth) from GIS and RS data. There are a lot of 2D flood software but these very costly. Is there any open source 2D hydrological model (software) for calculating flood depth over earth surface?
You can combine using both hydrologic and hydraulic model/software. The most easy hydrologic model for flood study is IFAS, because all of input data can be download from the software directly. The output of this model, then should be used for input in hydraulic model (hec ras).
- Glenn Melosh added an answer:1How do I incorporate surface and near surface fracture data in modelling groundwater flow in a crystalline rock terrain?
The data include scanline mapped data of fractures of outcrops, and remote sensing data for major lineaments etc. Thank you.
You should also incorporate information on the local and regional stress fields. At least at deeper levels (that can allow upflow of hot water) there are strong correlations between shear extensional zones at fault irregularities and hot spring or fumarole locations. Check groundbreaking (yes!) work by Curewitz and Karson (1997) and Jim Faulds et al (various). This information may allow you to at least qualitatively zone fracture patterns for likely permeability. Curewitz and Karson provide a "breakdown" radius that might help.Following
- Artha Ananda added an answer:5Which type of image data can accumulate due to use of social media applications?
Due to Social media applications like facebook, image data is accumulating. Which type (category) of images usually is it? E.g. In general image data can be categories as medical images, ultrasound images, Remote sensing images, etc.
If you retrieve the (raw) API data of Facebook, usually the "type" field of the posts are: photo, video, status, cover photo, link, event, status , etc. As fas as I know, FB has not classified them into more detailed "type" of image according to the source of image, if that is what you are asking.
- Jasper Maypa added an answer:64What is the best software for data analysis in remote sensing?There are many programs that can be used for data analysis in remote sensing, but, what is the best software for data analysis in this field?
I use QGIS and SAGA. The technology used in one software can be implemented in another without restrictions. Open source have large community support. If you have money, I think you better spend it to support open source projects. A lot more, not only people, will benefit from it. In times of crisis and calamities, open source is the way to go. Better spend your money for other more important tasks.Following
- Eduardo Marques Martins added an answer:3What are the aspects of Remote Sensing of flood monitoring?
How can a remote sensing out put of aspects of flood (mentioned below))be taken to the understanding of the general public, in order to maximize the safety , educate and precautions in a disaster?
Mapping flood-prone areas,delineating flood-plains,land-use mapping,Flood detection,early warning,rainfall mapping,Flood mapping,evacuation planning,Damage assessment
please feel free to add your comment suggestions.
I agree, is a good suggestion. You can use the APP to:
- Educational pourposes: with information of health and prevention;
- Safety/Security pourposes: with the GPS, the user can identify whether it is in a risk zone and (i don't know if it's possible) you can insert safety/evacuatioon routes which will be activated and displayed by the authorities in disasters situations.
For those that don't have/use cell phones, an alternative is hand out the review and summary maps of the analisys for the authorities to tansmite the information.
- Mohomed Mafaz added an answer:12Is there any mathematical method that I can use to convert 30 meter resolution DEM to 10 Meter?
I need 10 m DEM, but I have only 30 m DEM. Can anyone help me in converting a 30m DEM into 10m DEM? I have tried resampling methods in ArcGIS and ERDAS, but these methods are not sufficient for my study purposes.
Mathematically you could get a 10m resolution from 30m by applying various different algorithms, but practically when considering the accuracy it is no use for any analysis,
best way is you can purchase the 10m DEM if it is available, if not there are many advance methods of obtaining 10m resolution from 30m but as Michel M. Verstraete
mentioned you have to find additional data,one of the main way of obtaining the result is SAR interferometry where you can achieve your requirement but i don't think you are not looking forward to this so try the Sitender Malik suggestion.
Hope this is usefulFollowing
- Santiago Linares added an answer:5How do you calculate NDVI and classified NDVI?.
- Divyesh Varade added an answer:8Is it possible to discriminate clastic and chemical sedimentary rocks using remote sensing?
Also I have some other questions!
What about organic sedimentary rocks? Are multi-spectral sensors applicable in this case? Which one do you suggest and why?!
I am not sure but depending upon the size and composition of the rocks you might be able to use polarimetric interferometric SAR using an inversion model to see if you can estimate the di-electric constant for an area. However, this should only be possible with airborne imaging, coz the resolution would be too low for such rock sizes. Its an expensive and complicated way of doing things with little guarantee. In another case you might want to use a multi-sensor approach using both SAR and HSI.Following
- James Garry added an answer:3Is there a way of remote sensing Cs137?
I know airborne and low orbit remote sensing systems can have spectrometry inclined sensors and there are geologically orientated sensors to sense Uranium and Thorium, but does anyone have knowledge of a sensor that specifically targets Cesium 137 or would that be on the verge of Classified technologies?
My wish is to study the biological accumulation of Radionuclides in plants and possibly surface landscape features. Thank You. :)
What particular point would you like to know more about?Following
- 7Which satellites are used to estimate the wind speed at the ground level?Satellites to measure sea surface wind speed can take different data, But for the monitoring of land surface wind speeds, these satellites do not work.
Then, no way to estimate the wind speed at the surface of the land, except direct sampling, is not.(Of course far as I know)
You can use MODIS wind speed which is analyzed by NCEP. To gain more information about this product, you can refer to the following publication:Following
- Matej Knapic added an answer:11I would like to know who has experience in remote sensing and PLS-DA approach and its willing to work with my group in this project?
Thaumastocoris peregrinus is a major pest of eucalyptus in Brazil an we need to develop efficient methodologies to monitor this insect.
Can you provide more information about your methods? Which sensors you are planning to use? On what type of platform (e.g. airborne, satellite)?
PLS-DA can be done with varius software from R to Matlab. If you think we can collaborate on long distance way we could collaborate.Following
- 5How can I gate land surface temperature and what is used for the measurement of land surface temperature by a satellite?Land surface temperature.
I suggest you MODIS LST. I experienced its SST and it was good. To gain more information, you can refer to the following publication:Following
- 15Are there examples of using remote sensing to monitor near surface marine ecosystem health?I'm wondering if anyone has successfully used remote sensing (preferably multi-spectral aerial) to monitor/map near surface marine health? Specifically in the pacific north-west of north america.
I'm wondering if there is a known bandwidth that is provides reflectance from the seaweed, but not the water...
I used satellite ocean color data to monitor water differences in the normal and red tide conditions in the Persian Gulf. To gain more information, you can refer to the following publication:Following
- Hein Van Gils added an answer:8What is the best remotely sensed imagery for detecting invasive plant species in partially open forests?
If I wanted to detect a small (up to 3 m in height) invasive plant species growing within an open canopy pine forest (around 50% canopy closure), and differentiate it from other plant species (small tree species, for example), which of the available remotely sensed imagery products would you recommend? Phenology of the plant suggests that it emerges in April, flowers in August, then goes dormant in November. I may have LiDAR, but it is from one point in time - not sure the month yet. We may collect field measurement within sample plots.
What I miss is the seasonality of the dominant indigenous forest floor/under-storey species versus to the invasive. If different,, as is often the case, high temporal resolution imagery would be promising.Following
- Alvaro Semedo added an answer:4What does step mean in ECMWF Interim dataset (0-3-6-9-12)? Whats the difference between time and step?
I am working on ECMWF-Interim dataset, What does step mean in ECMWF Interim dataset (0-3-6-9-12)? Whats the difference between time and step?
... That is for sure the case with at least some of the wave parameters; check here:
Ole Johan Aarnes, Saleh Abdalla, Jean-Raymond Bidlot, and Øyvind Breivik, 2015: Marine Wind and Wave Height Trends at Different ERA-Interim Forecast Ranges. J. Climate, 28, 819–837.doi: http://dx.doi.org/10.1175/JCLI-D-14-00470.1Following
- Stefan Auer added an answer:12SAR simulator RaySAR with open access - which aspects are of main interest?
I'm planning to open the access to RaySAR, a SAR simulator I have developed within my TUM / DLR-group. Key features, applications and the scientific framework of the simulator are summarized in the attached PDF "RaySAR_properties".
Access to RaySAR would be devoted to the support of starters in science during their studies (as it did in my work) but also to experienced scientists lacking in 2D or 3D SAR image simulation tools so far.
As a first step along the road, I would like to collect feedback from scientists who would expect to benefit from using RaySAR.
Hence, my question is:
How may RaySAR support your scientific work?
(The answer may be given here, fostering the discussion of RaySAR, but also via e-mail to Stefan.Auer@dlr.de)
Update, 2016-01-12 (see also last post):
The RaySAR package can be downloaded on
In there, the following components will be found:
- A readme to start with :-)
- A documentation of RaySAR (please read it carefully in advance of using RaySAR) and the methodological background (doctoral thesis)
- A license file related to the use of RaySAR (GNU v3)
- The RaySAR source code (additional POV-Ray code parts, MATLAB code) and a related guidance how to set up RaySAR
- Model files to test the functionality and properties of the RaySAR simulation environment
I'm looking forward to feedback from the community and new developments / research aspects based on RaySAR :-).
A dedicated Google Group for RaySAR improvements / applications can be found on
Please take the opportunity to participate there in order to report your experiences and exchange ideas.
By the way: I have created a topic in the Google Group
where new RaySAR users are encouraged to post their first simulation results. In this context, I am curious to figure out which modeling environments are used and which workarounds may be necessary on the way to the goal.Following
- Achut Parajuli added an answer:12Where can I obtain free Digital Elevation Model data sets for the South-East Asia region (except ASTER and SRTM)?
The DEM resolution can be medium resolution (20~100m).You can see the earthexplorer website there are variety of image as well as DEM. Try the link first register their which is free
- 9Which image segmentation algorithm is suitable for a remote sensing image?I am doing my project on remote sensing areas. However, I don't know which image segmentation algorithm is most suitable for remote sensing imaging. I'd appreciate any suggestions.
I used different image segmentation algorithms in the following publications:Following
- Mustafa Üstüner added an answer:5How can I differentiate and classify the barren land, water bodies, dry water bodies and coal mining area in Radarsat 2 and AlosPalsar dataset?
I need to classify Radarsat 2 and Alospalsar data set using Support vector machine. I have the 5 multi component scattering parameters layer stacked individually for Radarsat 2 and AlosPalsar. I have total of eight classes namely Urban, Dense Vegetation, Sparse Vegetation, Barren land, Harvested land, Dry water bodies, Water bodies, Coal mining area. To get the ROI's of barren land, coal mining area, water bodies and dry water bodies are difficult as it gives almost the same backscatter values in the surface scattering component. Are there any ways of classifying the above classes in the mentioned data sets?
I agree with Prof.Gloaguen. If the data is not matched with your objectives, kindly change it. Or try data fusion with optical data.
If you solely use the RADARSAT data, you may add textural features or decomposition methods to improve the classification. There are some methods that can help you for better spectral seperability. You may check the article below:
Effect of Different Target Decomposition Techniques on Classification Accuracy for Polarimetric SAR Data
I also suggest you to analyse the data spectral response and training data characteristic. You may define the methods more proper up to the result of it.
See this article as well.
Haack BN, Khatiwada G; Comparison and integration of optical and quadpolarization radar imagery for land cover/use delineation. J. Appl. Remote Sens. 0001;4(1):043507-043507-16.Following
- Debasish Mondal added an answer:6How is PMU installed near a bus?
Can any one tell how PMU device is actually connected to an electrical bus? Meaning literally. Can a PMU be somewhere away from a bus? Should I really need to consider factors of geographical phenomena for that?
PMU can be installed through CT or PT with network bus where measurenet to be done. If the area is fissible for installation of PT or CT, PMU can be installed there.Following
- 9Is there a method to collect data of seawater salinity using satellites?
You know that it is hardly to get the data of sea water salinity but i think it is possible to collect data using remote sensing.
Yes, you can refer to the EOS site.Following
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