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6

Your understanding is correct. Obviously, you aren't limited to just two points in time, but that is only a minor variation. Multi temporal information is generally used for change detection, but it also provides a good tool to take phenological information into account when doing vegetation classification.


5

I hacked together a solution for this and wrote a blog article a while back on a very similar topic, which I will summarize here. The script is intended to extract a river from a 4-band NAIP image using an image segmentation and classification approach. Convert image to a numpy array Perform a quick shift segmentation (Image 2) Convert segments to raster ...


5

This is a known issue with ESRI. Their Page suggests these following workarounds (quoted from ESRI): Use one of the following two solutions to solve this issue. It is highly recommended to download and use ArcGIS Pro to perform all printing and exporting functions. ArcGIS Pro is not limited by the graphical device interface (GDI) ...


4

It's normal that azimuth and range resolution of SAR sensors differ, because they depend on different variables: The azimuth resolution (AR) of a SAR system is: AR=Length_of_antenna/2 The slant range resolution (SRR) of a SAR system is: SRR=(Speed_of_light*pulse_length)/2 The ground range resolution (GRR) of a SAR system is: ...


4

Otsu's method does not really care about actual values since it tries to minimize the total variance within classes while maximizing the distance between the classes. So, you could just run Otsu on your original data (no need to rescale) and it will provide you with the optimal threshold to use to achieve the goal listed above. I don't know what is your ...


3

NDVI is defined for any two bands with near-infrared and infrared data (it is an empirical remote sensing index). As such, you can calculate it straight from the DNs. This is mostly OK if you are only classifying or analyzing vegetation on a single image without significant atmospheric effects (cirrus clouds...) However, if you are performing change ...


3

RRD (reduced resolution dataset) files are no longer supported by ArcMap, since version 10.1 I believe. By the looks of that, you have an RRD, which is a pyramid set based on an original raster, but no the original data. ArcMap now uses a different type of pyramid with a .tif.ovr file extension. You should be looking for an associated jpeg, the original ...


3

Sentinel-1 data is published as Open Data, with attribution, see licence here. Registration required. An API is provided. See Scientific Data Hub for details. Software is also provided to process data.


3

1. where should I begin? Do you know what Image Classification is? If not here's an intro article ESRI wrote about for arcgis. You don' need arcgis to read it. Read it, and in the end you'll understand what you should need. Keep in mind that image classification is about creating classes. To do that should well defined classes beforehand (how many, ...


3

You could look at clustering in scikit-learn. You will need to read the data into numpy arrays (I'd suggest rasterio) and from there you can manipulate the data so that each band is a variable for classification. For example, assuming you have the three bands read into python as red, green, and blue numpy arrays: import numpy as np import sklearn.cluster ...


2

Your last attempt looks very promising. With more than 5 points you might get an even better picture. I use this transformation settings: Using as many border points as possible for georeferencing, I take the coordinates from the map canvas with the middle icon: and get this picture (with clipping to GADM borders):


2

When clipping the image it is likely that you removed the edge of the image. The edge of Landsat TM imagery is assigned 0 in all bands. This will result in 0 no longer being the minimum and a significant increase in the mean value across the raster. Furthermore, I would assume that you have also clipped the image to no longer include clouds, which would ...


2

We recently stubled across this issue as well and it is documented here: The merged LiDAR shows the trouble you report. The reason is that one flightline is much brighter than the other flightline so that the LiDAR points cannot simply be merged and have their intensity processed together. In the same flightline you also notice the negative effects of clouds ...


2

This effect could be a consequence of having different point densities within the flight line overlap regions. A possible solution would be to homogenize the LiDAR cloud. With Fusion the command line to accomplish such task is ThinData: ThinData allows you to thin LIDAR data to specific pulse densities. This capability is useful when comparing analysis ...


2

Yes, DXF supports embedded raster images. It saves them as BMP-type bitmaps, so no compression, mucho space bloat. They use type 310 tags, followed by the hex value of the raw image. I haven't figured out all the details. To see how it's done, create an AutoCAD drawing with an embedded image, as described in one of these sites: ...


2

Make sure you're using a 64 bit build of QGIS. The limitation on exported composer sizes/DPI is much higher on a 64 bit build.


2

Yes, you can use the acquisition_date in the metadata, which is the date in ISO format (YYYY-MM-DD). The date in the filename is Year+Julian Day. You can check the acquisition date against the filename if you wish using the NASA Julian Day Calendar This shows 2014-08-10 = 2014222


2

Don't use the OpenLayers plugin. Use the QuickMapServices plugin instead, as that works correctly with the map composer.


2

Use Raster Layer Statistics. It gives you. Statistics [html] Analysis results in HTML format. Minimum value [number] Minimum cell value. Maximum value [number] Maximum cell value. Sum [number] Sum of all cells values. Mean value [number] Mean cell value. Valid cells count [number] Number of cell with data. No-data ...


2

I can't answer really your question but I can tell you how to convert a georeferenced PNG to a GeoTIFF using QGIS. Method 1: add the raster layer to QGIS Layer -> Add Raster Layer... right click on the feature and click on Save as... chose the filename and selected the correct Coordinate Reference Systems (CRS, eg. EPSG:4326) and click okay. ...


2

Pulic accounts do not support file upload. From the doc page https://doc.arcgis.com/en/arcgis-online/share-maps/add-items.htm " In addition, organizational accounts can add image files and use the URL to show images in web apps, pop-ups, and so on. You need to share the CSV and image files with everyone (public) to see the URL in the item details page. "


2

I believe that your issue has to do with a known bug that reorders the position of the interactivity columns in custom infowindows. Perhaps the bug is just affecting one of the layers. I recommend to take a look at my response here: Cartodb image header doesn't show up after publishing the map I took a look at your interactivity data for your layers and ...


2

After some more digging I found out that the georeferenced image was too large. So I made tiles by using QGIS QMetaTiles plugin and accessed like this: var is = new ol.layer.Tile({ source: new ol.source.XYZ({ url: 'test/test/{z}/{x}/{y}.png' }) });


2

in the absence of NIR band, you can try the following index because the blue component is relatively high with respect to the red for most swimming pools. (blue-red)/(blue+red) (Borja Rodríguez-Cuenca and Maria C. Alonso, Remote Sensing, 2014) however, there might be confusions with shadows, therefore you need to predict shadow position (if you have a ...


2

If those lines are vector lines (and not graphic lines as well) and you want to places those pictures onto them you can just add a point layer and put points where you need the symbol. Then you use your picture as a picture-marker-symbol where you can set the background or transparent-color to no-color. If you need special rotations you can put the angle ...


1

I'm able to reproduce the behaviour on ArcMap 10.2. With no other changes: if the default Windows application for an image file is Windows Image Viewer, the link opens correctly in ArcMap if the default Windows application for an image file is Paint, the link doesn't work This seems to indicate that there is a bug in ArcMap 10.2 whereby a hyperlinked ...


1

Answered by Dietah on stackoverflow: To get the image in base64 I needed to include encoding: null as an option on the request. Answer: http://stackoverflow.com/questions/34341327/dojo-request-a-png-image-array-buffer-using-nodejs-and-return-the-image-to-the/36182182#36182182 I was looking to do a similar action but didn't found any answer. After some ...


1

I don't know if exists a better method for this question but, I found out this procedure: How to programmatically close a QMessagebox without clicking ok or X? where it was programmatically implemented a custom QMessageBox for automatically closing after a certain time. I tried out other methods (involving time python library) with your code but it was ...


1

Get the source of your image and asign the listeners: var lyrSource = layerPrec.getSource(); lyrSource.on('imageloadstart', function(event) { console.log('imageloadstart event fired'); }); lyrSource.on('imageloadend', function(event) { console.log('imageloadend event fired'); }); lyrSource.on('imageloaderror', ...


1

Right click the broken image and select properties. That should tell you the path where the webmap is looking for the image. Either copy your image to that location, or change the feature property in QGIS to the location of the image.



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