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6

If you are open to using alternative software to solve your problem, then I can suggest the Remove Off-Terrain Objects tool of the cross-platform open-source GIS Whitebox Geospatial Analysis Tools (of which I am lead developer). I realize that you said in your question that you could not convert your data to LAS format, but the tool takes a raster, not LAS ...


5

I'm guessing you never worked with SAR data before, so I'll break your question down into parts I can answer: 1) Create high resolution DEMs in GIS The process of creating a DEM just from SAR data is quite complex and requires a lot of processing power and memory. I don't know of a GIS software that implements DEM creation due to these constraints. 2) ...


4

The concern that I have is that lidar is not a systematic sample, as shown in your example. This data appears to have already been gridded and then thinned based on terrain or vegetation variation. Given the short-distance variation and observed spatial pattern of the clustering, my guess is higher point spacing was retained due to vegetation (e.g., trees). ...


3

The general terrain attribute that you are describing is called Relative Aspect (RA) and in its general form, it can be calculated for any input azimuth (Az) as follows: RA = Abs(aspect - Az) if (RA > 180) { RA = 360 - RA } where aspect is the terrain slope aspect calculated from the DEM. Here is an example of code that calculates the index ...


3

This is actually an exceedingly complex problem and not one that you're likely going to be able to solve using conventional ArcGIS tools. To do this, you'll need to develop for each depression in your landscape the relation between depth and volume, i.e. the depth vs volume curve, which will be uniquely defined for each depression based on it's form. To ...


3

I would have to say that without the original LAS point cloud, you will only be incorporating more inaccuracies into the data through raster manipulation. The DEM provided looks relatively clean for a heavily urbanized 1m resolution DEM. The "uplifted squares" are a result of triangulations across data voids, where the buildings are not included in the ...


2

The task could feel trivial by reading the gdalwarp documentation http://www.gdal.org/gdalwarp.html and GDAL AAIGrid -- Arc/Info ASCII Grid driver documentation http://www.gdal.org/frmt_various.html. The target pixel size is three times bigger than the native resolution 0.008333333333 degrees/pixel (not 1000 m/pixel, see the comments). gdalwarp -of AAIGrid ...


2

If you are not in an urban area, interpolating elevation from 4 meter point density to 1 m grid is quite safe, especially if your 1 m spacing reflects a larger roughness of your terrain (e.g. river bed). Make sure that you use an exact interpolator to preserve the elevation at known points, because LIDAR is precise and accurate.


2

In FME it would depend on the precise source format. If - as someone has suggested in the comments - the ASCII lidar is simply a series of x,y,z values then use the Point Cloud XYZ Reader, and a Writer such as LAS (or whatever point cloud format you want). Otherwise using a raster Reader (Esri ASCII Grid format?) and then use the PointCloudCombiner ...


2

Some things to consider: (1) Your problem is generally known as spatial interpolation because points are distributed in space, or surface interpolation because you are estimating the height of a point on a "surface" (which might be physical or abstract). (2) It's not generally a good idea to label to points in space as X,Y,Z because those letters are ...


2

Here is some of my C++ code for working with triangles: Structures, in order to understand my code understanding these structures is necessary: struct CoPair // linked list of coordinates { long ID; float X; float Y; float Z; CoPair *NxtPt; }; struct Tri // linked list of triangles made from 3 CoPair { bool Active; CoPair *A; ...


2

3D is not (yet) implemented in QGIS, but you can store the height in an attribute table field and create a 3D output manually with ogr2ogr -z_field fieldname outside QGIS. See Is it possible to create 3D dxf with OGR? for an example. This is rather 2.5D, because all vertices of a line must have the same elevation (as contours have). In QGIS, you could use ...


1

Design a flat raster surface for each height then run the Cut Fill tool. This will also give you volumes if needed. The Cut Fill tool summarizes the areas and volumes of change from a cut-and-fill operation. By taking surfaces of a given location at two different time periods, it identifies regions of surface material removal, surface material ...


1

I think it's the alpha band that's causing problems. To extract the data band: gdal_translate -of hfa -b 1 original.tif band1.img Then to warp: gdalwarp -of GTiff -s_srs epsg:4326 -t_srs epsg:3857 -co "tfw=yes" band1.img band1_warp.tif Gives an image: With GDALINFO > Driver: GTiff/GeoTIFF Files: D:\Testing\Tiff\band1_warp.tif > ...


1

You say you have ArcGIS, but you will need the Spatial Analyst or 3D Analyst extensions. I agree with the above comments. Use IDW or Natural Neighbor interp in SA. Set up the extent and the cell size using the environment settings. Could also build a TIN from these points then use the TIN to Raster tool.


1

You need to highlight all the attributes you want to appear in the output from the "Layers with fields/bands to get values from" list. If you have not clicked on 'EUD_CP_DEMS_3500015000-AA-86 : Band 1 (raster)' so that it is highlighted then you will get nothing. This is what the message: Complete the input fields and press OK... means (I think ...


1

A DTM raster can be represented by triangle meshes by finding a set of non-overlapping triangles that covers the entire mesh and approximates the elevation field. There are two different types of triangle meshes that can be used for this purpose: a triangulated regular network (TRN), in which every pixel of the raster is represented by a vertex, and all ...


1

The resolution is defined as 1/3 degree, that means three cells are one degree high or wide. Near the equator, the cells are square, but next to the poles they get to long rectangles, ending in a triangle at the pole itself. If you want a resolution in real meters on the ground, you have to reproject the data to a projected CRS. Then you will get the ...


1

In GRASS GIS, use r.in.arc for the import or simply r.in.gdal (Menu: File -> Import raster data -> Common formats import). This should read the file right away.



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