Questions tagged [dem]

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

244 questions with no upvoted or accepted answers
Filter by
Sorted by
Tagged with
2
votes
0answers
116 views

How to efficiently drape vector data over a DTM

I have ~100 million 2d vector topographic features (lines and polygons) in an Oracle 12c database. I have 20 billion xyz points in an Oracle database table as number types - the points cover the same ...
2
votes
0answers
51 views

How can I manipulate the number of points visible according to scale?

I've gotten trillions of points extracted from a DEM and they are to be labelled. It's fine at scales such as 1:500 but it gets too cluttered especially if I need to make maps of this with scales up ...
2
votes
0answers
48 views

infer the altitude from a DTM & finally provide it to point / evincere la altitudine da un DTM & finalmente fornirla a dei punti

I would like to complete a point vector's table with Z data. I am not able to take Z coordinate from a dtm (downloaded from http://www.regione.piemonte.it/geoscaweb/index.php?pgs2=0&pgs3=DTM10&...
2
votes
0answers
114 views

Drawing boundary through DEM of glacier valley using ArcGIS for Desktop?

I want to calculate/draw the boundary extent in Glacier valley with the help of DEM. Can you please guide me which is the best tools in ArcGIS and steps to calculate.
2
votes
0answers
1k views

How to convert shapefiles into ascii grid .asc in QGIS?

I downloaded multiple zips that cover a small island from the Rhode Island Geographic Information System webpage, specifically the geographic files that make up Block Island. Here's the source: http:/...
2
votes
0answers
1k views

DTM Extraction/Smoothing in ArcGIS

I have an .las file, intended to be a DTM (bare earth) that I generated from a photogrammetry software package that has come out just a bit too lumpy. I now have the license for that software tied up ...
2
votes
0answers
361 views

Whats the best way to create bathymetric contour lines?

I have a raster dataset with both Topographic and Bathymetric stored in it. What is the best way to create exact contours of the lake-bed? This becomes tricky when I want to make the contour for depth ...
2
votes
0answers
59 views

How many function templates can be applied to single image service in ArcGIS for Server?

I am trying to minimize space used on our server by producing a single image service for each county in Maryland. However, I need to display 6 different derivatives for each county: DEM in feet, ...
2
votes
0answers
357 views

Displaying DEM raster in QGIS

Using Raster>Analysis>DEM to display hillshade produces the message "gdaldem.exe had stopped working" so I asked the community. I'm new to QGIS, and I now realise after a little experimentation that I ...
2
votes
0answers
2k views

How to limit a specific area in order to have a topographic 3D map using MatLab?

I am using MatLab, I want to build a topographic 3D map, I am following this guide, I have been doing the steps listed on the section Draping Geoid Heights over Topography, and I do not have any ...
2
votes
0answers
88 views

Arcpy: Counting number of segments where altitude rises or decreases based on DEM?

I have a DEM of Sudety mountains and linear .shp with several hiking paths. I'm trying solve one problem: How to make a script based on input DEM and input line shapes that would count number of ...
2
votes
0answers
911 views

GDAL tiling DTED (dt2) dataset as gdal2tiles for 3D Maps

i am searching some webgl technologies to create 3d map with digital elevation data. for web tech. i have found ReadyMap SDK to create 3d map from TMS... in ReadyMap for elevation data it uses sth ...
2
votes
2answers
763 views

Converting vertical datum from WGS84 to EGM96 in ArcGIS Desktop?

I am comparing two different Digital Elevation Models SRTM (Datum: EGM96) Cartosat (Datum: WGS84) How to convert WGS84 to EGM96 in ArcGIS Desktop?
1
vote
0answers
20 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 ...
1
vote
0answers
18 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 ...
1
vote
1answer
48 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 ...
1
vote
0answers
30 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 ...
1
vote
1answer
70 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 ...
1
vote
0answers
34 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 (...
1
vote
0answers
13 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 ...
1
vote
0answers
17 views

Stacking lidar-derived height raster as ancillary data for segmentation in ENVI?

I get a a black and white image after following these steps. Does anyone know why I'm not getting a color aerial image beneath the mask? My setup consists of these steps: I mosaicked several NAIP ...
1
vote
0answers
56 views

Extracting Ridges from DEM ALOS

I'm currently working on a forestry project for my thesis. It consists of the optimization of skids tracks planification using ALOS images. To this end I would like to extract obstacles such as steep ...
1
vote
0answers
73 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 ...
1
vote
0answers
22 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 ...
1
vote
0answers
102 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 ...
1
vote
0answers
30 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 ...
1
vote
0answers
61 views

ALOS/PALSAR High Q DEM 12.5 Accuracy

Does anyone know the XYZ accuracy for the Phased Array L-band Synthetic Aperture Radar (PALSAR) DEMs (12.5 x 12.5 px)? Is there a document for reference?
1
vote
0answers
18 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 ...
1
vote
0answers
37 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 ...
1
vote
0answers
83 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 ...
1
vote
1answer
555 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 ...
1
vote
0answers
354 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 ...
1
vote
0answers
79 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. ...
1
vote
0answers
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 ...
1
vote
0answers
574 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) ...
1
vote
1answer
331 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
vote
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 ...
1
vote
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?
1
vote
0answers
65 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 ...
1
vote
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
vote
0answers
77 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 ...
1
vote
0answers
52 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 ...
1
vote
0answers
87 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 ...
1
vote
0answers
272 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 ...
1
vote
0answers
123 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 ...
1
vote
0answers
60 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) ...
1
vote
0answers
20 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 ...
1
vote
0answers
30 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 ...
1
vote
0answers
144 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 ...
1
vote
0answers
56 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 ...