Questions tagged [dem]

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

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24 views

Interactive tool for editing TIN data

I created TIN to generate DTM using Mass points from Lidar data and river data that I made from stereoplotting. TIN results show there are several locations where the river elevation floats. So I have ...
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31 views

Join DEM and GPS data point ArcMap

I have a problem using ArcGIS. I have generate a DEM raster with a 3D online software and exported it in ArcGIS. So I have a raster of my surface. After that, I have some GPS point (x,y,z) that we ...
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20 views

MicroDEM changes the aspect ratio of DEM

I downloaded a DEM from Open Topography (SRTM) and opened it in MicroDEM which changed the aspect ratio. The original DEM was 2329 px * 1679 px but that in MicroDEM when it was saved on disk was 2329 ...
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24 views

Elevation Map from Slope and Aspect Rasters

I am trying to create an elevation map (e.g., recreate a DEM) from the following input data: Slope Raster Aspect Raster ASCII file containing XYZ data points (Easting, Northing, and Elevation for ...
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1answer
162 views

Error creating DEM with Nearest Neighbour tool in QGIS?

I have an issue when I am creating a DEM with the tool natural neighbour on QGIS. When I extract my data directly on Qgis I have no issue creating a DEM. My points are coming from different sources ...
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86 views

GRASS r.sun returns “ERROR: insol_time and incidout are incompatible options”

I'm trying to measure irradiance on a DEM using the r.sun tool in QGIS 3.6. I have grids for the elevation (EPSG:32735 - WGS 84 / UTM zone 35S), the slope and aspect (EPSG:4326 - WGS 84). I've tried ...
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1answer
134 views

r.surf.area command of GRASS GIS is giving a very small area

I am a beginner to GIS systems and am trying to calculate the surface area of a dem using r.surf.area command of GRASS GIS. The surface area it is giving me is unacceptable as it is very small. It is ...
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54 views

Assessing quality (accuracy and precision) of digital surface model (DSM)?

I have been trying to build digital surface model from stereo satellite images. I do some initial research of it, it looks like I have to go outside and manually measure the height of an object (...
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14 views

Calculating SCS curve numbers using DSM instead of DTM

Are the curve numbers (calculated by SCS Curve number method) through DSM (Digital Surface Model) valid? Most of the SCS curve number studies focus on calculating curve numbers through a DTM (Digital ...
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2answers
396 views

Using Ground Control Points in Agisoft Photoscan?

I'm fairly new to the Agisoft Photoscan program, but I am trying to build several models using aerial imagery and highly accurate GCPs, with coordinates collected in the field. I align my photos and ...
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270 views

QGIS Exporting Layout as Blank PDF?

I am trying to export my map layout in QGIS3.4.5 on OSX 10.14. I've made the layout look exactly how I want it to look, but whenever I export to PDF, the PDF file is just a blank white page. The ...
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25 views

How do I compare multiple years worth of geomorph changes in a river while drawing one profile line?

I have many years worth of DEMs of a river I'm studying. I'm very, very new to ArcGIS (think one intro class), and learned how to use the 3D analyst tool. What I'd like to be able to do, is to draw ...
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213 views

Easy way in PyQGIS to convert a distance from meters to coordinates?

I am attempting to clip DEM rasters (USGS, in WGS 84) into a set of tiles measuring 2.56km on a side, in QGIS, using python. So far, it appears that gdal_translate is working for me, using a ...
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1answer
63 views

Generating DEM Generation in LPS?

I have a Cartosat 2.5 m Imagery and Block files along with DSM Data. I wanted to generate DEM using Leica Photogrammetry Suite Software. Does anyone know the steps of generating same? I have to edit ...
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47 views

Creating Left and Right Image pair to view with 3D goggles in stereo from DEM or Hillshade?

How does one create the stereo pair for viewing in a program such as StereoPhoto Maker? I have processed lidar that I'd like to turn into hillshades and then view in this kind of software, with 3D ...
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27 views

AW3D30: DSM file is grayscale 32 bits?

I downloaded multiple areas in AW3D30, but each time, the DSM file is 32 bit (instead of 16 as indicated in the specs), and the 32 bits are grayscale with the alpha channel always to 255. (I'll be ...
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40 views

White grid appears when reprojecting DEM in ArcGIS Desktop?

I am using ArcGIS Desktop 10.5. I have a DEM .tif archive, in WGS 84. The specifics are: Then, I try to reproject it to WGS 84 UTM 19S. Project and transformations -> Raster-> Project Raster I use ...
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110 views

Edit a raster (DEM) to create a constant slope angle

I'm trying to edit a raster (DEM) that has square sides (90 degrees) to create a surface with a constant slope angle of 18 degrees. I'm working in QGIS and have not been able to find any help for ...
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1answer
1k views

DEM reconditioning?

I'm using ArcGIS Desktop 10.5 Arc Hydro Toolbox & encountered a problem while trying to delineate watersheds respectively drainage lines. The red lines indicate my obtained drainage lines, which ...
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831 views

Rasterio Raster merge - horrible result

I am merging .DEM files from CUGIR NY repository, and need to merge files into one larger image for the whole of NY city. I use python 3.6 + rasterio; It works perfectly for all but one file - "The ...
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111 views

How can I merge a DEM mosaic with an overlapping bathymetry raster (while keeping only the portions of each that I want)?

I am tasked with merging a bathymetry raster with a mosaic raster I created from ArcGrid DEM Tiles downloaded from the National Map, for an areal extent spanning the Coastal Lowlands Aquifer System. ...
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16 views

Points on the opposing side of a breakline

If you have a breakline or even a single line segment within a DEM, how can you tell if two points lie on the opposing side of that breakline or line segment? From a computational geometry standpoint ...
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637 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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20 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 ...
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44 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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104 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 ...
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79 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 ...
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105 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 ...
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57 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 ...
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150 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 ...
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506 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 ...
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175 views

How to calculate Viewshed from a DEM file using a command line tool?

I need to take a polygon that show the viewshed given a point in a DEM file to ask the question: "What can I see from here to X kilometers ? " I already read this Performing viewshed analysis with ...
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71 views

Creating a polygon that shows the specific elevation above a river using a DEM

My goal is to determine the possible area covered by interpreted Tertiary drainages. To keep my example simple, I have a DEM and a River polyline. I would like to see the area a polygon (or raster) ...
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21 views

Extracting lateral averages using ArcGIS Desktop?

I want to do the following: to calculate the lateral average value of the surface aspect of a glacier (i.e. the average along a specific contour, the greenish lines). Can someone help me or say how ...
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37 views

Copy Raster for a Raster Mosiac with Function produces corrupted data

I am trying to export a ArcGIS raster mosaic dataset to a new raster that has a "Elevation Void Fill" function on it to fill holes in the data, but I am finding the function data is getting corrupted ...
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222 views

Two different cell sizes represented in a raster

I am currently working with a DEM with a cell size of 10 meters. I only needed a certain area of this DEM and wanted it at a 1 m cell size so I extracted by mask. I set the appropriate environmental ...
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60 views

Creating a bottom-top aggregated slope model in QGIS

I have a Slope model and would like to create a bottom-top aggregated slope model across a waste dump. So I am looking at creating this through the slope's mean values. One approach I thought of was ...
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817 views

DWG/DXF conversion to DEM file

I have got a detailed CAD drawing (DWG format) showing a house plan and topographic survey. I want to use the heights from the topo survey to create a digital elevation map in QGIS. I have tried a ...
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351 views

Co-registration of two DEM raster

I have 2 different elevation files, a ALOS GDSM elevation set & a DSM extracted from Corona imagery. Since the Corona file has some inevitable offsets (mainly in z, non-systematic across the area ...
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68 views

How to project DEM to satellite raster extent?

I want to run a urbanization model. Required data are; Classified raster data Slope etc. I've downloaded DEM data from USGS Earth Explorer. Downloaded data are in DTED format. I use EPSG:32636 ...
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95 views

trouble locating Bahamas DEM

I'm having a hard time finding a DEM for the Bahamas. North Bimini specifically. Does anyone have advice? Or a DEM?
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118 views

gdalwarp with DSM as DEM leaves shifted pixels in their original unshifted location

I'm trying to account for building parallax differences between images collected at different viewing angles. When I use a DSM created from VRICON data as my DEM source, I notice that building roof ...
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34 views

Misaligned .dem from Civil 3D into ArcMap

Imported 3 .dem files from a Civil 3D file. The two surfaces(topographic maps) fit correctly into my ArcMap file but the third surface, a bathymetric contour, seems to be misaligned and the scaled too ...
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539 views

Converting elevation from EU-DEM (ETRS89) to WGS84

I'm having a hard time trying to use elevation data from EU-DEM. This data is in ETRS89 (EPSG:4258), according to their site. Now, when I extract the elevation for a shore, I get 0 meters of ...
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94 views

Using CRS, DEM and Shapefile in QGIS?

I have a DEM of a region (metadata here) that I got from converting 16 las files using pointcloudviz. Now I have that loaded up in QGIS, and I have a shapefile I made from a hiking trip in that same ...
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121 views

Eliminating large plateaus in coarse resolution DEMs?

I have a 15-meter, integer DEM I converted into a float raster. However, the original DEM contains large lowland areas that are nearly completely flat. Due to the original resolution and integer ...
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509 views

Export of DEM in QGIS

Is ist possible to export a digital elevation model as .reb file es used in CARD-1 or Vestra?
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200 views

Solutions for generating grade/slope estimate heatmaps from a topography contour layer

Given a shapefile layer of 5-ft interval topography contour lines overlaid on google earth, I could, using the Ruler tool and some simple arithmetic, calculate average percentage grade numbers for a ...
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290 views

QGIS isolines from points and lines

I'm getting started with QGIS and I want to use survey data to generate isolines. Contour plugin works well except when surveyed area has linear details (say, a road) that are elevated relative to the ...
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247 views

Buffering based on topography in ArcGIS Desktop?

I need to do a buffer based on the real terrain. Like 500 meters from a polyline on all sides. I have DEM (SRTM) of the terrain. Is there a way to do that?

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