Questions tagged [dem]

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

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8
votes
1answer
98 views

Coarse Woody Debris extraction

I created very high dense point cloud of some forest plots using terrestrial laser scanner. Then removed points above 1.3 meter to see the coarse woody debris (Fallen dead trees). Attached is the ...
1
vote
1answer
363 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,...
2
votes
1answer
512 views

Understanding datum and elevation of NASA ASTER DTM?

I have downloaded some data from http://asterweb.jpl.nasa.gov/gdem.asp I would like to relate the elevations to some coastal data which is estimated to a specific ordnance dataum. Can anyone tell ...
-1
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0answers
13 views

Getting DEM for many small areas located all over world?

I need to calculate the average slope over an area for thousands of polygons with locations all over the globe. The polygon areas are small, less than 1 square kilometer. I have to use a consistent ...
2
votes
2answers
810 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?
4
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5answers
2k views

Elevation correction ASTER GDEM2 (+10m)

My ASTER GDEM2 has a average elevation error of -10m for my area. (I testet it using 90 defferential GPS reference points and compared it with old Topo25, SRTM, and GoogleMaps). I would like to ...
2
votes
1answer
29 views

Cutting/ exporting multiple terrain profiles to CSV files with QGIS?

I am trying to cut multiple terrain profiles and export them to CSVs (individual or combined). I have a shapefile of the profile lines, and a DEM to cut the profiles from. I can do this manually ...
8
votes
3answers
6k views

Getting subbasin area of each specified river segment?

I have a DEM file of one district, and I have used those following tools in spatial analyst tools in ArcGIS 10.1 to get files related to the original DEM file: Fill Flow direction Flow accumulation ...
0
votes
1answer
14 views

Stack for creation local shaded elevation tiles

I wish to create a local osm tiles with elevation information. I wish to display elevation info like a contour lines and shaded places linked with contour line values. I know about this source/...
8
votes
1answer
15k views

Creating DEM from Point Data using QGIS?

My boss gave me a small 3D-point-shapefile and asked me to make an DEM from it, which I should put together with an older DEM of the same site, which was made with Surfer. I created a raster-layer ...
2
votes
1answer
29 views

Where to extract Esri ASCII Raster Files?

In my spare time I am working on interpolating algorithms for Digital Elevation Models in C++. I always obtained my elevation data set as the ESRI ASCII Raster format because it is super simple. ...
0
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0answers
22 views

Least cost path creating unwanted straight lines

I’m very much a beginner with GIS and I’m stuck creating a least cost path. Basically, I’m trying to highlight which river valleys would most likely be flooded in the event of a volcanic eruption ...
0
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0answers
19 views

How to apply the xyz translation vector derived from IceSAT altimetry to an ArcticDEM strip?

Laser altimetry data from the NASA IceSAT spacecraft is used to compute x, y, and z offsets for ArcticDEM strip files. The values of these offsets are contained within the DEM metadata, but are not ...
-1
votes
0answers
32 views

Error using rsaga.fill.sinks

I'm using RStudio to delineate a watershed, and have had some difficulties when using rsaga.fill.sinks. My code up to this point is as follows: #set rsaga working directory and version number myenv &...
0
votes
1answer
26 views

Transfering height information from DEM to line feature to use in profile with ArcGIS Pro?

I am using ArcGIS Pro 2.4. I want to make a height profile of a line segment. The line has no height information, so I want to transfer height information to the line from a dem. How can this be ...
0
votes
0answers
22 views

Applying low pass/median filter over DEM in GeoTIFF format using ArcGIS Desktop?

I want to apply a median/low pass filter (over a few hundred kilometers) over my DEM to reduce the noise. I tried ArcGIS focal statistics tool but no luck. I got a blank GeoTIFF file. How can I do it ...
1
vote
0answers
11 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 ...
2
votes
1answer
29 views

Using data from 30-meter DEM map to fill into missing pixels in 8-meter DEM map

I have a DEM map of 8-meter resolution, where some groups of pixels are blank due to the clouds (I guess). Is there a way in ArcGIS or GRASS to fill into those null areas with data from 30-meter DEM ...
3
votes
1answer
38 views

Creating DEM Contour files from shapefile line data in QGIS

There are many question occurring on this forum regarding this issue, however the issue I am facing has not been answered in Generating DEM from contour Shapefile using QGIS?, which is that I have ...
3
votes
0answers
44 views

Removing noise selectively from DEM using QGIS?

I am looking for a processing tool that can remove noise selectively from a DEM (Mostly SRTM). My current workflow includes "Fill sinks" and "r.neighbours". The problem is that the tool is blind to ...
0
votes
0answers
9 views

Getting elevation data of a location using ALOS data

I'm working on a program to determine the line of site that a particular point will have using the ALOS data set from JAXA. So far I've managed to download a data set, and am a confused on where to go ...
0
votes
1answer
12 views

How to Converting stream definition threshold to extract drainage network to metric scale?

I extracted two drainage networks from a DEM of 30 meters resolution with two stream definition thresholds: 1000 pixels and 500 pixels. Can you tell me what this thresholds represent in terms of ...
0
votes
1answer
867 views

Importing DEM in ASCII format into ArcMap and Projecting it? [closed]

I have been trying to import an ascii grid file into ArcMap. However, I am battling to project the data. Can anyone assist? I've tried defining the projection but to no avail. The data should be ...
1
vote
1answer
748 views

Problem or ERROR in converting from raster to vector!

I wonder if anyone could help me out, i am kind of a beginner at QGIS. I´ve built a DEM for a project that i am developing than i´ve made the slope raster with the terrain analysis,it seemed that ...
7
votes
3answers
4k views

Producing wire frame images from DEM? [closed]

As part of a project for a wind turbine assessment, I would like to make a wire frame image to compliment my Viewshed / line of sight and Photo montage. I have never created a wire frame image from ...
-1
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2answers
46 views

Open DEM in Google Earth?

How can I upload my DEM to Google Earth? Agisoft Photoscan allows exporting Google Map tiles in Export DEM option but I have no idea how to upload it to Google Earth.
0
votes
1answer
42 views

Digital Terrain Analysis - Roughness Index [closed]

Currently I am working on a project dealing with terrain analysis based on a DEM. I came across the term "roughness index" using slope values from that specific DEM. On YouTube I found a video, which ...
1
vote
1answer
39 views

Editing specific portions of DEM using ArcGIS Desktop?

I currently have a DEM for an east coast city. Unfortunately, the elevation of an area containing a Dam is not accurate. I have the correct elevations as reported by the city. How would I go about ...
0
votes
0answers
29 views

Using MERGE command in QGIS?

I am working on QGIS 3.4.9 with Mac OS Mojave 10.14.5 I have two DEM raster files and I would like to merge them. Unfortunately, an error occurs and I don't know what to do.
0
votes
1answer
47 views

QGIS - processing area and calculating volume of polygon with know elevation from a DEM

I got a DEM of a watershed and I need to create a dam at a fixed elevation (with a rectangular polygon corresponding at the top of the dam) and calculate it's area (including the slope (fixed value) ...
0
votes
1answer
25 views

Getting started with ArcScene?

I have been using ArcGIS for some time and am playing around with arcscene for the first time. I am having trouble getting started. When I add a DEM to a blank project it renders as a uniform grey, ...
5
votes
4answers
4k views

Creating DSM and DTM from a LAS using a freeware solution

Is it possible to export a surface and terrain model files from an aerial, LiDAR point cloud (LAS) set? I am using SAGA GIS for very basic operations, but I couldn't find this option (and I have a ...
3
votes
5answers
8k views

Can I convert ESRI Grid (DEM) raster to USGS DEM?

There is a tool for DEM to Raster in ArcGIS but I need to convert my ArcGIS DEM rasters (mostly LiDAR) into USGS DEM. The idea is to import this DEM into Sketchup and create a "sandbox" TIN surface ...
2
votes
2answers
3k views

Extraction of DEM from netCDF file into ASCII XYZ format

I need to extract a DEM of a waterbody from a netCDF file so I can ultimately convert the DEM into xyz format. I'm not sure how to go about doing this, and so far, I have tried to create raster layers ...
0
votes
0answers
30 views

Using Viewshed Analysis in ArcGIS Desktop to Find Points Where Entire Area is Covered?

I have a DEM of an entire state and I would like to do a viewshed analysis. But instead of me using existing points to determine the viewshed, I would like to find all points where the entire state ...
0
votes
1answer
719 views

Hillshade is block grey in ArcGIS Desktop?

I am trying to create a hillshade on my DEM because I need to be able to distinguish features which I can't do in its current state (see picture). However, when I add the hillshade, it adds a block ...
1
vote
0answers
21 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 ...
3
votes
3answers
2k views

What DEMs does QGIS support?

I am working on QGIS rasters. What DEM file formats are supported by QGIS? I know that QGIS can read the GDAL supported formats but not what the GDAL supported formats are. I do not know whether ...
1
vote
2answers
56 views

Comparing several values within each cell of a DEM

I am working with a DEM and got a GPS line of my working area. I converted the GPS line into single measurement points. Now I want to compare each of these GPS points with the corresponding elevation ...
0
votes
1answer
210 views

Clip tool in ArcGIS Pro not working?

I'm trying to clip "Terrain" raster I downloaded from the portal (https://www.arcgis.com/home/item.html?id=58a541efc59545e6b7137f961d7de883) in the shape of a polygon (a country's boundaries) by using ...
2
votes
2answers
84 views

Mapping coastline geometry with SRTM raster?

Working on a map that includes a bathymetry layer, SRTM data for hillshade, and an accurate coastline boundary edge. I noticed though that the pixel resolution of SRTM 90m resolution creates visible ...
3
votes
1answer
69 views

CHM (Canopy height model) = DSM (Digital surface model) - DTM (Digital terrain model)

I want to create a canopy height model (CHM) which has the height of objects (trees, building, etc.) from DSM and DTM. Below is the step by step procedures which I did so far. I use open source s2p ...
0
votes
0answers
15 views

Inverse values in raster heightmap

I have just converted a point vector into a tif using Rasterize in QGIS. And values are currently: How do I completely flip the values as it should be Min -98.95 and Max 2.3 I can't find much when ...
0
votes
1answer
59 views

Finding lowest elevation in multiple polygons using DEM? [closed]

I have a polygon layer with six polygons. I need to have the lowest elevation point in each polygon using a DEM. The following explanation https://support.esri.com/en/technical-article/000011761 (...
1
vote
0answers
19 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 ...
2
votes
0answers
24 views

A GeoTIFF heightmap from SRTM embeds vertical planes along lat/lon grids in its 3D representation

I've downloaded an SRTM GeoTIFF from Open Topography and converted it into the grayscale image before I imported it into Blender to improve the quality. It is apparent that vertical planes are cutting ...
5
votes
1answer
606 views

Hillshade shows grid texture artifacts

I tried to make an hillshade and a slope map from a DTM using QGIS but the result shows some artifacts. As you can see in the picture there is a grid texture in the hillshade and the slope map. I ...
2
votes
2answers
162 views

Are two rasters the same, including null values, in ArcGIS desktop?

I am working on a task to calculate Height Above Nearest Drainage (HAND) - that is the height above the nearest point along the flow path that is on a drainage - not the geographically nearest ...
4
votes
2answers
841 views

Generate Height Above the Nearest Drainage (HAND) using QGIS

I have a DEM I want to generate a HAND for and want to do so in QGIS. Does anyone know of any plugins or the processing steps to be able to do this?
3
votes
2answers
3k views

Spatial Analysis - Calculate a cells elevation (height) above the nearest stream cell

I have searched for some ideas on how to formulate this analysis, but have come up short. I imagine there is a pretty straight forward answer; any help would be greatly appreciates. Data: DEM, 1/...