Questions tagged [dem]

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

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1answer
870 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
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1answer
758 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
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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
58 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
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1answer
54 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
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1answer
40 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 ...
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0answers
30 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
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1answer
59 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
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1answer
27 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
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4answers
5k 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
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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
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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 ...
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0answers
31 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
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1answer
728 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
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0answers
23 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
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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
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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
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1answer
241 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
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2answers
86 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
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1answer
89 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
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0answers
16 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
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1answer
60 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
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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
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0answers
25 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
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1answer
637 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
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2answers
163 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
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2answers
882 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
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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/...
0
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2answers
105 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 ...
1
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1answer
59 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
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1answer
27 views

Performing DTM compression using ArcPy?

I have a set of 32-bit TIFF files of DTM data (50 sm) and I need to save them as 16-bit. In order to save some space, I compressed them using LZW algorith and saved as 16 bit tiffs using Arcpy. But ...
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2answers
38 views

Seeking Uruguay or South America DEM or DTM? [closed]

Is there any DEM (Digital Elevation Model) or DTM (Digital Terrain Model) for Uruguay or South America? I am aware of the Renare for Uruguay.
33
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2answers
40k views

Creating DEM from contours in QGIS?

I have a shapefile with contours and their heights. Is it possible to make a DEM from contours in QGIS without using GRASS? I found Creating DEM from contours using ArcGIS Desktop? but the answer ...
11
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2answers
46k views

Creating DEM from contours using ArcGIS Desktop?

I have a large set of contours that I received broken down into several different subsets. I have merged most of the subsets together creating a larger set of contours in three different files. I have ...
0
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0answers
17 views

Finding the local extrema contour line on a DEM

I need to trace the top of a small levee on the side of a riverbank, based on a DEM. This line is similar to a contour line, except that it goes through the local maximum instead of a constant level....
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0answers
36 views

Creating DEM from contour pyQGIS? [duplicate]

How can I create Digital Elevation Model using python codes in QGIS software?
1
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2answers
41 views

Cannot read pixel value from DTM raster with QGIS

I am using this DTM: http://ags.cuzk.cz/arcgis2/services/dmr4g/ImageServer/WMSServer?request=GetCapabilities&service=WMS At ArcGIS I am able to ready pixel value of the raster but at QGIS it ...
1
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1answer
83 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 ...
3
votes
1answer
56 views

Generate a viewshed and merge it with another image using GRASS/GDAL command line? [closed]

I've found a tutorial showing exactly what I want to do (merge viewshed and hill shade or map) but unfortunately it is for QGIS users and I need it in pure command line instructions because I'm in a ...
1
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0answers
439 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
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2answers
59 views

Creating contour file from DEM?

Using a 3-meter DEM, can I create an accurate 5 feet interval contour file? Or is the minimum interval contour I can get is 10 feet (roughly 3 meters)?
-2
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2answers
55 views

Learning DEM resources? [closed]

I'm starting on a problem where I need to find the high point inside a polygon that exists inside the bounds of a DEM tile. I'm teaching myself GDAL and I'll be using Python to access the GDAL library....
2
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0answers
60 views

Generate an accurate DTM with photogrammetry?

I generated imagery from a low flying drone (40 M AGL) equipped with a mica sense RedEdge multi-spectral camera and have processed the imagery in PIX4D and now am attempting to do some analysis in ...
0
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0answers
36 views

How to remove bridges and dams from DEM

Is there anyway to alter elevation of DEM where there are bridges and dams for the flood routing of the River? I have to calculate discharge of the River from ancient times so at that time there ...
0
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0answers
22 views

Flow Distance Not Calculating for Entire Raster

I am trying to calculate the height above the nearest stream for an area. The problem is, it only does so for a portion ( the colored area below) of my area of interest. In the pic below, the black ...
0
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1answer
35 views

Why is my DEM so bright for some tiles?

I downloaded an SRTM DEM GeoTIFF file from Earth Explorer. It looks fine when previewing it on Earth Explorer (see picture) but when added in ArcGIS Pro the DEM looks too bright in some of its tiles.
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0answers
21 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 ...
0
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1answer
38 views

Extrude building footprints using raster (DSM) values in ArcGIS Pro?

Is there a way to extrude a buildings footprint shapefile into 3D buildings using values from the area's DSM in ArcGIS Pro?
1
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0answers
194 views

Detrending DEM in floodplain?

I am after the same solution to Removing elevation trend over sloped surfaces? I am following the steps outlined, but in the last step it states: In this expression [X'] refers to the the x-...
1
vote
1answer
95 views

Creating 3D image from HGT files?

Is there any command line tool to create a 3D terrain from a DEM SRTM HGT file like this? I mean, given a camera position, a HGT file and a satelite image. EDIT 1 First try to adapt mdsumner's ...