I downloaded calibrated/corrected Landsat 8 data (Level 2) from ESPA () to do land cover classification. But there are many corrections and calibrations can be done as listed below and maybe more, such as:   - Surface Reflectance  - Top of Atmospheric   - sensor zenith and azimuth   - solar zenith and azimuth    - geometric   - radiometric   I am not sure all of them were processed on the scene. What are the must do corrections/calibrations for Land cover classification analysis?
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There is a neat Surface Reflectance product of Landsat imagery. I know the difference between SR and raw products: SR presents calculated values, that are supposed to represent state of the Earth surface, while "normal" products are disturbed by all kinds of scattering on the way from the Sun to the surface and back to the sensor.  Now, I'm performing a land classification of terrain to extract boundaries between two types of land use. I have many images and this is unsupervised classification. Do I really need SR product here? Would I need it, if it was supervised classification? I suppose it's no in both cases, as I don't directly compare any values between images. I just need to know exact position of this boundary.
105856
I work with Blender 2.81a and I have a problem with some artifacts in the shadows of objects with smooth shading. Based on the release note of Blender 2.81 ,(), I expected this problem to be solved. There’s a note with a comparative screenshot saying: “Reduced shadow terminator artifacts for bump mapping with diffuse BSDFs.“   There’s no detail about the issue. There’s a mention about “bump mapping”. I have another scene with bump mapping and the problem is the same as in my test shown below. Here’s a screenshot of my test below.  The only solution right now is to increase of the number of polygons with a “Subdivision Surface” modifier. However that makes a crazy amount of polygons and the modifier cannot fit all situations.  Another element of solution is about the light. I noticed that happens particularly when there’s one directional light in the scene like a sun light. Increasing the “Angle” parameter creates a smoother effect. Too much of this becomes blurry and unrealistic. My screenshot shows a sun with the angle 6.4 degrees.  These artifacts only happen in Cycles. Eevee seems to be correct.  I expected this problem to be solved. However it is still present. Am I missing something?
114635
I was wondering if anyone knows of a plugin, extension, process, etc. for mapping shadow locations based on date/time using raster data? I have searched and what I have been able to find all seems to require vectors or multipatch data. I have DSM rasters produced from LiDAR and would ultimately like to use those as the source for identifying locations of shadows, as I would like to the surrounding features in the raster to be used as sources of impact (i.e. trees). I am open to all options, but QGIS, Grass, and ArcGIS are preferred.
50977
It seems like it was possible to do this with Google Imagery if I recall but is there any way to determine the date of collection of Esri's World Imagery basemap (or other basemaps) at a given location?   Something I read indicated that this was updated Sept, 2014 but I don't think that has anything to do with the date of collection.     I have been telling people that it is 2014 Imagery but I've been challenged on that statement because features on the landscape are showing up that have reportedly been removed.     The basemap I'm most interested in knowing about is .
60006
I have looked at solutions to what seem to be somewhat similar problems but they don't seem to solve my problem.  A georeferenced raster layer loads into the correct location in relation to other layers, so CRS is obviously OK, but has this black background which I don't know how to remove.
13612
I am using ArcGIS 10.1 to generate a DEM (bare earth) from LAS dataset. To accomplish this, I use Las Dataset to Raster tool as described in .  I have read here and there in the web that the the cell size of the output raster should be set at a value corresponding to the average LAS points spacing; somewhere else, they suggest to use a value that is three times the average point spacing.  Now, since I wish to produce a bare earth DEM (i.e., with only ground returns), I am wondering if the cell size has to be set at the average point spacing of the whole LAS dataset (i.e., comprising non-ground, ground, etc), or exclusively of the ground points?  On the basis of the ArcGIS's point file information tool (), I managed to get statistics for each LiDAR class. The average spacing (whole dataset) is 1.5 m, while for ground points only is 0.67.  Any insight into the issue?
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I have downloaded classified LAS data from    I am trying to generate accurate DEM and DSM for further analysis. I created a LAS dataset with a projected CRS of  NAD_1983_UTM_Zone_19N in meters and the z CRS in meters as well. My question is on which classifications do I choose for the DEM and DSM. Here is the filter options I have in my dataset:     According to unh LiDAR data report class 2 is ground.     What I have done so far:  DEM I chose the class 2 points and used the las dataset to raster.   DSM In the predefined settings I chose first return and used the las dataset to raster tool.   Is this an accurate way of generating these two rasters? Do I not have to take into account the the unassigned class 1, noise class 7, reserved 11, reserved 17, reserved 18?  Additionally (I can ask this as a separate question if it gets requested to), when using the las dataset to raster tool the sampling value is defaulted to 10. I would like to change it to 2 or 3 (would be meters) to match the LiDAR resolution. I also plan on using the generated DEM and DSM for a least cost path analysis and I want them to be higher resolution. Will making the sampling_value 2 or 3 throw off the results or should I leave it at 10?
109234
I am attempting to fully automate the process of georeferencing a load of .png files - i have xml file containing the co-ordinates - but how can i use them?  Does anyone have any advice?
27250
I originally had an IMAGINE Land Cover raster file that I opened in ArcMap.   I used the Extract Feature from Raster to extract only the Developed class and saved it (still IMAGINE).   Then I used the Copy Raster to convert the IMAGINE to GeoTIFF, but when I try to view the GeoTiff in Google Earth or Photoshop, it doesn't display anything.   However, in ENVI, it displayed successfully.   What am I doing wrong?
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In my daily work, I am constantly asked to calculate areas of global raster datasets in geographic projection at 30 arc second resolution. These datasets are normally the result of a Combine operation (a typical example is a vegetation classes combined with country layer). To do this, our unit created a raster dataset with the area of each pixel in geographic projection at 30 arc second. With this area grid, a zonalstat is performed to sum the areas for each class. Since I am not sure how this area grid was created, I always wondered whether this approach is more accurate of just reprojecting the raster in a equal-area projection (from simple tests the results of the two methods are similar). Does anybody experienced a similar situation?
66395
In ArcMap 10.2 I have a DEM and my aim is to change its color ramp using ArcMap, then export this colored raster as a geotiff (8 bit).  I checked "use renderer" and "force RGB" options but the results are not good (EDIT: when viewed in ArcMap). With some color ramps, the results are really off, and with others, they are slightly off.  For example:      Is this a bug, or is this an artifact stemming from the the original image being simplified into an 8 bit image? (Does ArcMap stores its color ramps with more than 8 bits?)     it seems that results only look strange in ArcGIS - if viewed in other applications, colors look right.   So why is ArcMap displaying the exported rasters inaccuractly?   Do I need to change some settings somewhere to have them display correctly?
83277
I'm looking for recommendations on best practices for dealing with raster data layers with different resolutions and projections. The advice I've been given is to always resample to the layer with the lowest resolution before performing any analysis, but this seems like huge waste of precision to me and I've never been given a solid explanation for why it should be done.  When is it reasonable to resample to match a higher resolution grid and what are the implications compared to resampling to a lower resolution?  I realize that this is likely highly situation dependent. I'm mostly looking for general guidelines, but here's my specific scenario for reference:  Scenario: I'm looking to construct a spatial regression model predicting land use based on a variety of environmental and socio-economic layers. My land use map is Landsat derived and hence 30m resolution. Examples of explanatory layers include the  (3 arc-seconds, ~90m) and  climate layers (30 arc-seconds, ~1km).
42279
I have two rasters: a digital elevation model (DEM) and a Landsat band. The grid resolution of both is 30 m, but the grids are not coincident (see image: the dark raster on top is the DEM; the light raster underneath is the Landsat band).  I want to perform some transformation of the Landsat band so that its grid aligns perfectly with the DEM grid. I've tried resampling the Landsat band to 30 m in ArcGIS using the DEM as a Snap Raster in the Environment settings, but this does not have any effect. I've also tried clipping the Landsat band to the extent of a vector polygon (that the DEM is also clipped to), while setting the DEM as the Snap Raster, but to no avail.  I suspect this is happening because both rasters are already at the same resolution (just on different grids), but I really need their grids to be aligned to be able to do any further analysis.  Can I do this in ArcGIS Desktop?
79541
I am working with Landsat 8 image acquired in 2014. I am trying to convert the raw image (DN) to Top Of Atmosphere Reflectance/Radiance (i.landsat.toar) in Grass 7.1 (still under development). The reason for using this version is that it is caters for landsat 8. I specify the metadata file and load the information etc. I get the same error every time:      ERROR: Unable to open header file for raster map    Base Name of input raster band: LC81700832014160LGN00_B1@PERMANENT  Prefix for output raster maps: LC81700832014160LGN00_B1.toar Name of metadata file: C:\Users\carinswart\Documents\GIS_DataBase\Landsat8\GHT\09June14\LC81700832014160LGN00_MTL.txt   I have tried to be careful not to leave gaps in my file names.
20806
I just upgraded to QGIS 3.0 (OS X as well on Windows 10) and can not find out how to do some georeferencing. I am told by the software, that GDAL georeferencing is still installed and that I could not remove it, and that it should be in the category "raster". But I can not find it there, also not in other parts of the menu.    new profile created, but the same issue...:
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Explanation of the problem:     On 31 May 2003 the Landsat 7 Enhanced Thematic Mapper (ETM+) sensor had a failure of the Scan Line Corrector (SLC). Since that time all Landsat ETM+ images have had wedge-shaped gaps on both sides of each scene, resulting in approximately 22% data loss. These images are available for free download from the USGS GloVis website and are found in the L7 SLC-off collection.   source:   Can I use Qgis instead of proprietary software (ENVI, Erdas....) to fill the gaps?
96879
How do I change the coordinate value of a vector layer (13293061,-572595) to 119.413,-5.13677 (vector data &amp; Google Earth do not match)?   If I output my data using Google Earth as background, the vector data does not match with the underlying google layer.   Printing the result to PDF also has this same problem.