Questions tagged [dem]

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

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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 ...
0
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0answers
20 views

What are the steps I go through to generate contour lines from one of the quickmap service layers e.g. OpneMapSurfer ASTER GDEM…? [on hold]

I want to generate contour lines for a relatively small remote area in Australia but my only source data is the free public data from the quickmap services options. What do I need to do to go from ...
0
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0answers
26 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
715 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
19 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 ...
0
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0answers
1k views

Assessing Flood Hazard Risk Zones using DEM? [closed]

What is the best effective way to quickly estimate flood hazard risk areas using DEM data? Ideally I am looking for guidance to move forward and perform this process over large areas (i.e. entire ...
0
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0answers
14 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, ...
0
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0answers
30 views

Using Drone for Deliveries? [closed]

My company delivers medical supplies to health facilities in a some sections of an African country. This year we are expanding to cover over 2000 more health facilities. I've been brought on board to ...
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
45 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
179 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
81 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
57 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
13 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
58 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
28 views

Extracting Z coordinate from DEM - Python

I'm writing an algorithm in Python to extract Z coordinate of an DEM for a pair of X,Y coordinates. I'm using GDAL. The algorithm works correctly by extracting the Z coordinate from the DEM: Z = ...
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 ...
2
votes
0answers
23 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
578 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 ...
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 ...
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
815 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/...
0
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2answers
69 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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0answers
21 views

SurfaceArea function of R giving very big unacceptable area for DEM?

I have been trying to calculate DEM area using surfaceArea function of R. It is giving a very high unacceptable erroneous area. I have a 10 m by 10 m USGS DEM file. I read the DEM using raster() ...
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 ...
0
votes
1answer
31 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) ...
1
vote
1answer
24 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 ...
0
votes
2answers
33 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.
32
votes
2answers
39k 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
votes
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
votes
0answers
15 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....
0
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0answers
34 views

Creating DEM from contour pyQGIS? [duplicate]

How can I create Digital Elevation Model using python codes in QGIS software?
1
vote
2answers
39 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
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 ...
3
votes
1answer
52 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
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
2answers
53 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
votes
2answers
52 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
votes
0answers
44 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
votes
0answers
24 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
votes
0answers
19 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
votes
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.
0
votes
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
votes
1answer
25 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
vote
0answers
180 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
75 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 ...
0
votes
1answer
32 views

Switching Mars DEM elevation values from negative to positive?

I'm using a DEM of Mars I got from UA's HiRISE website, and I want to convert it into an STL for 3D printing using the DEMto3D plugin. However, the raster values are all negative, so I thought I ...
0
votes
1answer
70 views

EU DEM in GRS80 EVRS2000 with geoid EGG08 --> Make it comparable to Black Sea 1975 for Romania

I got contour lines for western Romania in vertical system Black Sea 1975 which is based on elevation data with 100 m resolution. Now I would like to compare that to the EU DEM with higher resolution. ...
2
votes
1answer
62 views

Converting DEM (TIFF) files to terrain files?

I want to create an app to show 3D using ol-cesium. In ol-cesium example it use cesium terrains, But I want to do it with my DEM files. How can I convert my DEM (TIFF) files to terrain files?