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Arhanghelul last won the day on September 25 2016

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About Arhanghelul

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    Kingdom of Heaven (RO, east Europe)
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    NIHIL SINE DEO ET .....GIS ! :)
  1. Question: Where can I find and donwload free SPOT satelite images ? I have read a year ago that the SPOT1-4 archive will be free, similar to Landsat archive. What is the status for SPOT images ? Download links for SPOT ?
  2. I don't think so. If satellite imagery with <2 m in spatial resolution would be free to download like Landsat, then private company like DigitalGlobe, Aibuse and others what they will sell to coustomers ?
  3. And remember that you will also need to learn how to use the softwares. eCognition Developer it has a lot of algorithms and functions, good for change detection using high resolution images (under 5 m, from commercial satellites and images from UAV/drones).
  4. 260/250 mb/s This is almost half of the maximum speeds of my ADATA Pro SP550 series SSD, because my laptop mainboard is limited to max. 3Gb/s. But still, is much faster compared to my HDD...
  5. I have just replaced my 320 GB HDD-drive 5400 rpm with a 240 SSD from ADATA in my leptop. Now the multiresolution segmentation algorithm in eCognition Developper is working better, is much more faster and the maximum image size to process has increased from 4000x4000 pixels to 7000x7000 pixels (I am using the same CPU and RAM configuration). So, now i see that SSD's are more efficient thant classic HDD's.
  6. Where do you have ERDAS 2016 ? Share a download link, please.
  7. Hello ! I would like to know what would be the best and the medium PC configuration required to run eCognition Developer in good performance. I read on eCognition forum that this software needs a lot of RAM memory, especially when we use the Multiresolution segmentation algorithm (MRS). It also needs a good CPU and plenty of hard drive space on the computer. These problems can be solved by using eCognition Server, but most of us have a crack license only for eCognition Developer. So we are limited to the performance of our PC's. I am looking to buy a new PC and I would like to know what would be the best configuration to run eCognition Developer in good performance. Can you give me some general tips ? What CPU to use (Intel, AMD, Gz) ? Mainboard, the type and the RAM producer ? HDD or SSD ? My budget: @1500 USD (without the LCD monitor or any other peripherals parts) Thanks, my friends !
  8. Where can I find some international online GIS & Remote Sensing courses organized by institutions or companies that issue graduation diplomas for their students ? Thank you !
  9. Maybe there is a problem of content of moisture in the soil that makes buildings and soil very similar, so maybe you should select another Landsat scene from a dry season. Have you tested with another Landsat scene for your area of interest ?
  10. NDBI = Normalized Difference Built-up Index search the formula for Landsat in Google You can't escape the problem of mixt pixels between built-up and bare soil. These 2 elements have similar spectral signatures. You can only maximize the spectral differentiation by using derivates like NDVI, NDBI, NDWI, etc.... as aditional bands in Landsat scene classification. There is some other supervised methos to better separate the elements, like Spectral Angle Mapper (SAM) , etc, etc. search on internet and on ENVI help page, on sub-pixel classification methos. Another method is to use OBIA > eCognition. OBIA is based on image segmentation. Segmentation is grouping similar spectral pixels into objects. Then you classify these pixel groups based on their spectral signature, shape, area, texture, position into the image, etc. OBIA is similar to visual image interpretation and classification But some research articles say that OBIA is inferior to traditional per-pixel classification methods (supervised and unsupervised) in the case of medium and low spatial resolution images like Landsat, ASTER, SPOT 1-4, MODIS, etc. OBIA works better on high-resolution images like WorldView-2&3, Quickbird, Pleiades, IKONOS, orthophotos, etc (<5 m spatial resolution). These images are much better for built-up area extraction compared to Landsat. So, in your case, my friend, it depends on the accuracy of the classification that you want to obtain !
  11. This is an interesting topic. I have also asked myself how to integrate landscape metrics into eCognition to classify different building shapes in urban areas from high-resolution images and to estimate the degree of urban landscape fragmentation. If someone has a solution to this problem, please share !
  12. I have found this: and this: and this: Who is using one of the filters to his UAV ?
  13. Lurker, how do you place Ground Control Points (GCP's) if for example you must fly your drone above a dense forest or a wetland with low or no accessibility ?
  14. I have 2 questions for Lurker: 1) do you need a special permission, a legal document to fly a drone in your country ? For example in USA, drone operators need to register (and to pay a fee) to Federal Aeronautical Agency, and similar situation is in some west European countryes ? How is in Indonesia ? 2) do you use Ground Control Points (GCP's) marked on the the land surface with the GPS when you fly your drone, to produce accurate orthophoto mosaics ? Thank you. Arhanghelul
  15. Hello members of GIS AREA ! Drones, also named UAV's or UAS's, are becoming increasingly popular for different applications. Me, I am interested in the field on drones applications for remote sensing, more exactly for aerial mapping, to produce orthophotos, Digital Terrain Models (DEM) and other products which are very useful for research or private businesses. I would like to know more about how to build a personal drone from 0, how to selected the best platform for the application of aerial mapping, how to fly the drone and how to process the datasets obtained from drones. I know that, on this forum, there are some people who are using drones and it would be great to share some knowledge, some practical information to others interested in UAV drones. Let's see what can we do. Is someone interested to participate to this ? My best regards, Arhanghelul