Questions tagged [dem]

For questions about Digital Elevation Models (DEM), Digital Terrain Models (DTM) and Digital Surface Models (DSM)

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54 views

Adaptive raster to points sampling based on change of slope in QGIS?

I have a high resolution elevation map and need to convert it to XYZ points. Simple conversion generates a lot of points in flat / constant slope areas which are redundant for 3D terrain generation. ...
1
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1answer
579 views

Using Color Ramp Manager Plugin in QGIS?

I followed instructions mentioned here and installed the Color Ramp Manager by choosing install experimental plugins as well. Now, when I go to Properties > Style > Single Band PsuedoColor and I ...
0
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1answer
79 views

Saving NDVI TIFF file as txt file in ArcGIS Desktop?

I have to use elevation data (dem.tif) and NDVI data (ndvi.tif) as covariates for regression kriging and I want both these files as txt files. How do I do this?
1
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1answer
80 views

Generalizing slope raster in Mapinfo?

I am working on calculating a slope raster in Mapinfo using a 15cm DEM derived from a LiDAR point cloud and the output data will have 3 predefined breaks displayed so I need to blur those relatively ...
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0answers
578 views

Openlayers in QGIS - Errors in opening google satellite/

End goal: To put contour lines with lat&long layers from a google earth location (Rock Piles beach, HI) in QGIS. I plan to use CRS: EPSG:3760 Does the Plug in (Openlayers / QuickMapServices) ...
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0answers
25 views

Reduce or heighten a DTM with overlaying polygons

I am using QGIS 3.01. I have a DTM over a historic area. There has been done archaeological surveys there, which suggest that the ground was several meteres below todays surface many hundred years ...
1
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1answer
366 views

cesium quantized mesh generator

We are trying to develop pur own quantized mesh generator and visualize these terrain tiles on CesiumJS. As an input we use SRTM data that belongs to north parth of TURKEY. We generate contours on DEM,...
1
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1answer
142 views

Changing DEM resolution when creating a slope raster? [duplicate]

I want to create a slope map using a LiDAR DEM. I think that I should use the slope tool; but I need a slope map with a 2m resolution and I'm not sure how to do that. How can I have a slope map with ...
1
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1answer
149 views

Blocky Raster from TIN. How to increase resolution?

So i am trying to create a seamless DEM using a DTM created in pix4d with a 5cm resolution (Raster). I have then collected RTK bathymetric data which i have turned into a TIN below To create a ...
0
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1answer
75 views

Elevation shading of linear feature compared to surrounding ground level in QGIS

I have a digital elevation model (DEM - geoTIFF) in QGIS 3.2. There is a linear feature (earth bund/wall) in the DEM that I would like to shade/colour based on its elevation above the surrounding ...
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0answers
18 views

Adding small-extent rasters to DEM

My goal: create viewsheds for observers which also incorporate the heights of buildings which could block observer view. This is using archaeological data, and is representing time change -- so I need ...
0
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0answers
160 views

Generate XYZ coordinates of DEM mesh/grid

Is there a way to generate a wire grid of plain text XYZ coordinates starting and ending points for each wire segment? I want to generate them from a digital elevation model. Preferably with gdal/qgis ...
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0answers
37 views

Obtaining a smoothed DTM?

I am use AcGIS 10.1 and have a DTM with an 8 m grid resolution. Which tool could I apply to smooth the surface?
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1answer
50 views

Creating a constant surface at designated height above river [closed]

I am trying to create a polygon (and eventually a raster) surface of river deposits that have since been eroded away. We know that at maximum, deposits got up to 600 ft above the present river. Given ...
1
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1answer
235 views

Convert several xyz data into a homogenous raster data with GRASS?

I am new to GRASS and Python and I have to convert a huge amount of *.xyz data into raster data using a batch process in GRASS. So far it works good, but when I put the created *.tif data into QGIS ...
3
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1answer
52 views

Merging convoluted raster DEMs - what is this method and why use it?

This is more a theoretical question than practical, and I'm referring to 3x3 convolution kernels with online demo and the first comment after it. I have a raster elevation model and want to turn it ...
2
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0answers
80 views

QGIS: How to find a line with defined slope starting from a point over a DEM? [closed]

If I have a DEM as raster layer and a point with defined position in a point layer, how could I generate a line with defined slope of e.g. -1%? The end point can be anywhere and should be defined by ...
2
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2answers
173 views

How to create “roof line” for a general polygon area?

I have a polygon with an arbitrary shape ( assume that it is well-formed with no self intersection, no duplicated points etc), and I need to subdivide the polygon into sub-polygons like how one would ...
1
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0answers
67 views

Integrating use of surface distance when calculating cumulative cost-surface based on walking pace?

Disclaimer This question is somewhat related to a number of earlier questions of mine: Accumulated cost surface (Tobler's hiking function) ignoring slope using R gdistance?; Calculating ...
4
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2answers
502 views

Is D8 flow accumulation algorithm still suitable for watershed computation if terrain contains lots of flat area?

My question is inspired ( and similar) with my previous question. But this question is more concerned about the suitability of D8 ( or in general non-dispersive) flow accumulation algorithm for ...
1
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1answer
182 views

Flow accumulation algorithm open source code in C++ on Windows

I'm looking for flow accumulation open source implementation ( C++ or C# would do, Python no), on Windows, preferably the source code comes with Visual Studio project files so that I can just build ...
0
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0answers
41 views

QGIS - Average a DEM into a single, flat plane

I have a XYZ point cloud that I am interpolating into a DEM. The data represents a surface that is relatively flat. I am hoping to be able to create a DEM of a single flat plane that best represents ...
1
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1answer
202 views

Failed to execute EucAllocation - arcpy

Im unable to get EucAllocation function working in ArcMap 10.5.1 or via Arcpy. I've used user guides for info but with no joy - http://desktop.arcgis.com/en/arcmap/10.5/tools/spatial-analyst-toolbox/...
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0answers
72 views

Photogrammetric point cloud classification

My question is regarding the point cloud classification and editing work for a photogrammetric point cloud generated using drone based imagery. My objective is the generation of a digital elevation ...
1
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1answer
140 views

Mapserver / QGis and DEM GeoTIFF different nodata values behaviour

I Have a problem with novalue datas in my DEM… This is the workflow I did: my DEM datas are in multiple Arcgis ASCII grids… Each .asc files have a header containing "NODATA_value -99999.00". I ...
5
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1answer
295 views

DSM quality lower in ArcGIS Pro than PhotoScan

I am processing aerial photos collected with an automated drone flight into orthomosaics and DSMs, and have noticed the quality of outputs produced in PhotoScan is much higher than those produced in ...
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0answers
81 views

ArcGIS hillshade creates artifact on tile boundary

I'm working with ArcGIS on a DTM made of 1x1km tiles (cell size 20cm). When I try to create an hillshade model based on this DTM I get visual artifacts on tile junctions, whereas there are no visible ...
4
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1answer
254 views

Selecting LiDAR return point type in LiDAR dataset with ArcPy?

I am trying to create a Digital Earth Model (DEM) using ArcPy under ArcGIS Pro 2, but I am running into some problems. I can generate a DEM within ArcGIS Pro by selecting only the ground points ...
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0answers
53 views

DEMs not displayed properly in 3D in ArcScene and QGIS

Some of my DEMs are rotating about an axis off the screen, if that makes sense. I defined them with a CRS of GCS 1984 and projected it in UTM. I am only loading one at a time to provide perspective ...
0
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1answer
60 views

Comparing DEM volume using GRASS

I have two DEMs of an open-pit mine taken a few weeks apart. I would like to estimate the volume that has been excavated during that interval, ie the difference of volume between the two DEMs. Can I ...
2
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1answer
114 views

Elevation contours from .JP2 / .J2W files?

Is there a way in ArcGIS, Global Mapper, or CAD to generate elevation contours or any sort of surface data from a .JP2 file? I've never been provided this format before and our client is telling us ...
1
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0answers
92 views

QGIS .adf file saved as GTiff changes elevations

I have got two .adf DEMs which I need in GTiff format so they can be merged. When I 'Save As' the layer as a GTiff, the resulting output has elevations which are inconsistent with the original .adf ...
2
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0answers
84 views

Using Spherical Standard Deviation to identify ledges on steep cliffs? [closed]

I have been implementing the approach highlighted here: Finding regions or zones in raster DEM of similar slope or aspect values in ArcGIS for Desktop? to calculate firstly the "spherical variance" ...
6
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1answer
167 views

Lidar DEM produces odd results related to topographic aspect

Background: ArcGIS Desktop 10.5.1, Spatial analyst We have acquired two bare-earth DEMs derived from lidar. YEAR2007 was produced in 2007, and YEAR2015 eight years later. Both are 32-bit, floating-...
0
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1answer
220 views

How to load DEMs from custom source in Maperitive?

Maperitive has the ability to handle DEM files. I have read that it can handle .hgt files (which is what I have), but how can I load them? Using set-dem-source complains about some missing xml. Does ...
1
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0answers
53 views

Fill gaps in dem created from .laz file [duplicate]

I've been trying to fill those lidar scan lines in my dem with no avail. Is there any way to interpolate those "gaps" to get a clean dem? I used las2dem to create the dem from .laz file
2
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0answers
90 views

Viewshed analysis adding polygon mitigation in QGIS?

I am looking at a DSM layer in QGIS and have created a binary viewshed using the viewshed analysis plugin. I want to add a polygon layer with heights to add on top of the dsm layer to indicated ...
3
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0answers
68 views

NODATA on MapServer

I am trying to generate a DEM mosaic to publish via a WCS using MapServer. Unfortunately I can not remove the NODATA. In MapServer's own tutorials and discussion groups suggest PROCESSING "NODATA = 0",...
2
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1answer
506 views

Converting DEM to LAS file? [duplicate]

Is there a way to convert a DEM raster to a .las file using open source software and/or any tools that come along with a complete ESRI license? I have been able to achieve this using the LAS Toolset ...
2
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1answer
214 views

Calculating floodplain for river section using DEM only in ArcGIS Desktop?

I'm looking to create areas where water might go when a river floods its banks. I have a pretty good resolution DEM (5ft^2 for each "square"). I'm not looking for anything super accurate or precise ...
3
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1answer
185 views

Extracting only elevation data from NASA's GLAS Satellite LiDAR to create raster DEM?

I'm trying to open data downloaded from NASA's Earthdata site in ArcGIS 10.4.1. Specifically I'm trying to open "GLAS/ICESat L2 Global Land Surface Altimetry Data (HDF5) V034" (Image below, ...
-1
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1answer
183 views

Bringing drone maps into QGIS, CRS and scale bar [closed]

I'm looking for a guide to bringing files into QGIS so that the scale bar in print composer reads accurately. At the moment the files I'm bringing in are Geotiff and DEM. I know this has something to ...
4
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1answer
153 views

Use DEM elevation attributes in vector polygon?

I am modeling glacier retreat scatching polygons on DEM surface trying to come out with 3D scatch. Is it possible to adjust "height" of polygon to follow elevation of DEM surface (eg. glacier height ...
0
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0answers
56 views

DEM provided contains high elevations (trees) that I wish to remove - is this possible

I wish to remove trees off my 3D aerial (high elevations). The files provided are .tif - unfortunately the trees are causing quite a bit of noise. Is there a way to set an elevation to remove them? ...
3
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1answer
91 views

Generating a buffer of a vector line based on raster values where the vector intersects a raster

I am trying to figure out how to buffer a vector shapefile with a variable distance (in QGIS). However, the variable distance needs to be dependent on the value of a raster (DEM) where that vector ...
1
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0answers
295 views

Removing contour artifacts from low slope regions

I am generating contour lines from a DEM using QGIS and the python console. The process generates many small circles in regions of low slope (little black circles) that detract from the long connected ...
2
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1answer
130 views

How to estimate the standard error on the mean difference between two DEMs?

I have two DEMs of the same area measured on two different dates. Differencing these DEMs gives a map of the change in height between these two dates. I would like to calculate the mean change in ...
3
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1answer
265 views

Different DEM range values in QGIS and ArcGIS

I downloaded a raster image from USGS for a part of Malaysia. I opened it by QGIS and ArcGIS Desktop as shown in the attached photo. The first problem is that some values are in a negative and the ...
0
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1answer
108 views

Batch scripting r.in.lidar in pyQGIS for LiDAR DEM output? [duplicate]

I need to use pyQGIS to write a script that will run the r.in.lidar GRASS 7 on a set of LAS files. I am terrible at Python, but I need this for my task. I would like to process as a batch. How can I ...
2
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0answers
207 views

GDAL merge of DEM data resulting in large black tiles, elevation min/max problem?

I am new to QGIS (former Arc user) and having trouble with the raster merge tool. I am merging 7 tiles of SRTM arc 1 data to cover a province in eastern Ecuador. Data is resulting in large areas of ...