New answers tagged dem
1
This is the classic "new to GIS" problem. It happens to everyone, and it may or may not be because of something you did. Sometimes GIS data just doesn't come with the correct projection data encoded in it. You're doing well so far. Don't panic.
Good job using a base map to figure out which layers are correctly located. You've narrowed the problem down ...
0
CRS/projection issues can be tricky working with QGIS. Important: check:
1.) which CRS does the QGIS project have?
2.) which CRS do raster file and point layer have?
do they match? Check for their EPSG codes. It could be that one of your layer is in a projected CRS (like your Monte Mario Italy) and another layer is in WGS84 for example.
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You can try the function 'blur' in the package 'spatstat' to apply a kernel based blur (Gaussian or otherwise) to your image. You can perform multiple iterations or adjust the parameters of the function until you achieve the desired result.
library(spatstat)
DEM_blurred <- blur(DEM, sigma=0.5, kernel="gaussian")
#adjust sigma value to change the ...
3
This error is resulting from an error check within the function.
if (length(dim(x)) > 2) {
warning("data must be grayscale image")
}
Given this condition length(dim(x)), a single band rasterLayer class object will always return 3 representing row, column and nlayers dimensions.
Whereas this function, in theory, operates on a matrix object it is not ...
0
SOLUTION: I used TauDEM to correct the stream network using the DEM. Below are my results. It is still not exact but it is a huge improvement and definitely usable for my work. Here is a link to a useful guide for anyone using TauDEM for their first time: http://hydrology.usu.edu/taudem/taudem5/TauDEM51GettingStartedGuide.pdf
1
Sometimes it is easier to look into ArcGIS help:
http://desktop.arcgis.com/en/arcmap/10.3/tools/spatial-analyst-toolbox/minus.htm
You can see, that it is Raster1 - Raster2.
So difference between 2014 and 2016 is Raster1(2014) - Raster2(2016). Which would be 0 in same areas. Negative in areas that are higher in 2016 and positive in areas where 2014 is ...
0
QGIS has a simple and effective plugin named "Serval" that I believe will help you out. To install Serval, select Plugins > Manage and Install Plugins > All > and scroll down to Serval, and click the Install Plugin button. A Serval toolbar section is thus created.
Using Serval is pretty straightforward. It has 3 modes:
Probing: Use this mode to change ...
1
If you are using ESRI products and you have point data with the proposed final elevation values of your project you can create a TIN from those points. Convert the TIN to a raster. Then replace that portion of the DEM with the raster version of your berm and pond. There is a lot of help to get you there online and these steps use standard tools.
Some ...
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A solution is to get the DEM elevation values of the same points xy coordinates (red lines projections in the figure below) using osgeo.GDAL or rasterio to read the DEM, GeoPandas for the points shapefile and affine to get the elevation value (see Python affine transforms).
With GDAL
from osgeo import gdal
from affine import Affine
import geopandas as gpd
...
0
I found this elsewhere which worked a treat.
If your raster layername is RasterA, then try (RasterA@1 >= 0) * RasterA@1
2
You can also use QGIS (which is open source) and/or Blender plugin Blender GIS.
Using QGIS, you can make a SHP (shapefile) out of a DEM and with Blender GIS you make a mesh out of the SHP (see this question and this question), or, you can import SRTM directly into Blender using only Blender GIS.
1
Try this approach:
Under QGIS save the raster as GeoTIFF from Raster -> Conversion -> Translate (convert format).... This is actually an interface to the underlying gdal_translate.
(optional) Open the GeoTIFF in GIMP or Photoshop
(optional) Save the file as simple TIFF
Open in Blender
Screenshot of the gdal_translate interface.
Make sure you select UInt16....
0
There is a Python code for this on the ArcticDEM page:
"Strip DEM files are provided at 2-meter spatial resolution in 32-bit GeoTIFF format. Elevation units are meters and are referenced to the WGS84 ellipsoid. Strip DEM files include metadata text files describing the xyz offsets to filtered IceSAT altimetry data, although these translations have not been ...
1
Is it possible to use other software? I mean CloudCompare. It is free software that will generate geotiff quickly and easily in a few clicks. I made a simple gif with sample asc file:
1
Picture below shows talweg, generated by using flood depth and flow paths derived by using Hydrology tools:
As one can see flow paths depict channel shape in a well defined valleys without depressions along it. If there is one, results are random.
What is happening on a flat terrain is absolutely out of control, your pictures illustrate this nicely. So in ...
2
Your data is not a regular grid, you have missing points. The XYZ format description specifies "no missing value is supported".
Below is an image of a small section of the western edge of the data visualised as points showing the missing values.
To convert your data to raster, you can use gdal_grid. gdal_grid doesn't support the full range of OGR open ...
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You can take you LAS files and add them to an LAS Dataset in ArcGIS. Then, use the LAS Dataset tool to filter the point cloud for different returns. Finally, use the LAS Dataset to Raster tool to create surfaces from your LiDAR data. See this link.
2
Have a look at QGIS2threejs. It allows you to export a terrain model to a web viewer. it's available as a plugin, just search for it in the plugins dialog.
https://plugins.qgis.org/plugins/Qgis2threejs/
There are settings for draping a DTM with an ortophoto, as well as extruding polygons and so on.
Not sure if it works out of the box with a mesh geometry, ...
1
That's a easy task with rasterio. For each band the data is accessible as a kind of array.
So:
import rasterio
# Which band are you interested.
# 1 if there is only one band
band_of_interest = 1
# Row and Columns of the raster you want to know
# the value
row_of_interest = 30
column_of_interest = 50
# open the raster and close it automatically
# See ...
0
I think you need to create a points dataset from the coordinates then use the Extract Values To Points tool, if using ArcGIS Desktop or ArcPro.
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I tried this solution of mosaicing to a folder instead of FGDB, it worked for some of my projects but still had gaps in others. After further experimentation, I found that recalculating the pyramids to 0 for all the raster tiles first, then mosaic to new raster, was successful in creating the full mosaic without gaps. Possibly a combination of this plus ...
1
This is just a display issue that stems from GIS software defaulting the color scale bounds to match the min and max values displayed in each tile of your DEM. To make them match, simply change the bounds of all of your images to the same values, making sure that you choose min and max that are small and large enough, respectively, to allow for all of the ...
2
Measuring the elevation along a transect is a bit like measuring the length of a coastline. If you change the resolution, you change the final result, but none of the result is relevant if you don't mention the scale of the measurement. If you look at a portion of soil with a binocular, every grain of sand will be a cliff. If you fly high on a plane, only ...
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