Questions tagged [dem]

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

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60 views

QGIS Display Attributes as Z Value for Point Shapefile?

I would like to create a state map that displays a 3D bar chart for each of 20 colleges (mapped as points) showing the percent share of engineering degrees earned by award level (i.e., assoc, ...
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72 views

Change detection using DEMs of difference and error quantification

Im currently working on a project in one of my seminars at university ("Advanced methods in natural hazard research"). We are modelling DEMs with Agisoft Photoscan using pictures from flume ...
34
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3answers
4k views

Creating transparent hillshade?

I get elegant transparent hillshades via a combination gdal and convert. Compare to grey-based hillshade commonly used, such transparent hillshades are very cool because they can be placed between the ...
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0answers
16 views

DEM colour themes add-in for QGIS [duplicate]

Is there any plugins / add-ins for QGIS that give more of a variety than the default colour ramps?
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1answer
144 views

Splitting DEM at certain elevation?

I have a DEM that includes bathymetry and terrain elevation and I would like to split it at the coastline. Ideally, I would end up with one tif that's land and one tif that's bathymetry. I have ...
0
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1answer
39 views

Viewshed Analysis for Custom DEM file [closed]

I am new to qgis and trying to do 2 things. My objective is to have an accurate viewshed analysis at the end. But my DEM file is of poor resolution. I do have a shapefile with building height ...
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0answers
16 views

Calculate average slope values for a point using 50ft vector perpendicular to contour

I am trying to calculate the average percent slope of a hillside on either site of a data point. I tried extracting info from a DEM using a radius around the point, but I believe a more accurate ...
0
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1answer
81 views

Merging 1m DEM to 30m DEM?

I have a base 30 m.Dem . However, i also have 1m Dem for an area of interest only. I would like to overlay the 1m Dem on the 30 m Dem meaning the area of interest will have 1m and the rest 30m. Is ...
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0answers
28 views

Creating DEM in GRASS?

I need to create DSM and DEM with resolution 0.4 m. I tried to create DSM with resolution of 1m, everything was ok, but when I set higher resolution, then raster have a stripes with No Data values. ...
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0answers
35 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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1answer
62 views

Line of Sight Analysis using Points and DEM

I have a DEM and a point feature class with the elevation value from the DEM as an attribute plus with x number of feet added to it representing a tower location. I would like to do a line of sight ...
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1answer
98 views

Resampling 0.7 m LiDAR (in raster already) to 10 m DEM in R?

How do I resample the 0.7 m LiDAR to 10 m DEM in R? What are the basic rules for checking the consistency?
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35 views

How to retrieve GIS data in Multiple Orthophoto at point level

I have been using a python script that can read Data from Orthophoto(*.tiff) of size 300Mb-2Gb. But this is taking 32s per request of lat-long, which is not ok. I have different Orthophotos with ...
3
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2answers
879 views

Generating DEMs from point clouds and differencing them?

I have two point clouds obtained via structure from motion (ground photos of sand-dunes + Visual SfM/Agisoft Photoscan). If I wanted to generate a DEM from these point clouds and difference them to ...
1
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0answers
78 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?
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0answers
22 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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35 views

How can I change the elevation of a lake on a DEM so I show the lake bottom contours?

I'm studying the drainage of a lake and I have a DEM of the lake and the surrounding area. I already identified the shorelines of ancient lake levels at higher elevations, but I would like to keep ...
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0answers
41 views

Erroneous contour polygons in QGIS 3

I have a global DEM and try to calculate contour polygons for 4 different heights in QGIS. In the first image below, you can see the colored DEM (white = lowest; yellow = higher; orange = highest) as ...
1
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1answer
84 views

Converting RTK Elevation Data to DEM?

I have a shapefile that contains elevation data. I want to eventually convert this to a slope layer. I'm assuming I have to convert to a raster, then a DEM, then slope. Is that correct? If so, ...
100
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6answers
156k views

Differences between DEM, DSM and DTM?

I am listing some of the acronyms used in our work and had to stop to think about whether to list these together or separately: DEM: Digital Elevation Model DSM: Digital Surface Model DTM: Digital ...
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1answer
226 views

Reclassify and combine rasters in QGIS?

I have a vector layer containing watercourse location which I have rasterized. I also have a DEM containing elevation data for the region in which the watercourses are located. I would like to ...
4
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1answer
247 views

Cropping raster and merge it to overlapping DEM?

I am working with an existing DEM of a river and its surrounding area in QGIS (actually a virtual raster from four separate DEM TIF tiles). My goal is to add a bridge's profile to the DEM. I have a ...
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0answers
10 views

Creating terrain polygon buffer from line using ArcMap? [duplicate]

I have a line in a steep hill, and need a 400 meter buffer on each side of the line. I know (roughly) how to create buffer on a point, but not a line. Can someone help me here?
11
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5answers
3k views

Are there any open source tools to detect and fill sinks on a DEM? [closed]

Are there any open source or inexpensive tools to detect and fill sinks on a DEM? ArcGIS Spatial Analyst is just out of my price range.
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1answer
233 views

How to load DEMs from custom source in Maperitive?

Maperitive has the ability to handle DEM files. I have read that it can handle .hgt files (which is what I have), but how can I load them? Using set-dem-source complains about some missing xml. Does ...
7
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6answers
2k views

Converting DEM into areas of “flatness”, with arbitrary fill/cut to area ratio? [closed]

I want to find areas of relative "flatness" in a DEM. How can I find flat areas? I want to find a neighbourhood of contiguous cells that have an elevation variance that is within a certain ...
1
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1answer
188 views

Flow accumulation algorithm open source code in C++ on Windows

I'm looking for flow accumulation open source implementation ( C++ or C# would do, Python no), on Windows, preferably the source code comes with Visual Studio project files so that I can just build ...
2
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1answer
591 views

Why ground model from point cloud in Global Mapper is inaccurate?

I have a LAS file that I assumed was based on LiDAR, but it is actually based on ADS (airborne digital sensor) imagery, according to the body that captured the data. I load the file in to Global ...
3
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1answer
82 views

Interpreting cell coordinates from DEM?

I'm using Environment Agency DTM LiDAR data which I import into Mathematica in ASCII format to produce ground surface models, sections, etc. The process works fine, but I'm unclear whether the cell ...
1
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2answers
124 views

Getting grid points for DEM purpose that is bounded by surveyor points?

I have a list of surveyor points, and I will need to create a DEM model out of it ( in geotiff format if possible for space consideration, if not, then in ASCII grid format). I need the DEM for ...
3
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3answers
204 views

DEM of difference - estimate the error - simple method

I have two DEMs of the same area, measured at two different dates. Subtracting one from the other, I can create a DEM of difference (DoD) to find out about the volumetric change in m³. DEM 1 has a ...
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0answers
42 views

Smoothing/denoising DEM to prep for 3D printing?

My DEM was generated from contour lines (as well as break lines and point height data), and the contours persist in the DEM despite doing some basic denoising (although i may not have used the optimal ...
4
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1answer
70 views

Using NAVD88 geoid in Northern Canada?

The USGS NED (1-arcsec) dataset is available for the continental US as well as most of Canada. It is based on the NAVD88 vertical datum. I am interested in using the DEM to orthorectify SAR scenes in ...
2
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1answer
87 views

How to Calculate area of LULC at different elevation by using zonal statistics as table tool [closed]

I have to calculate the area of different land classes like forest,barren land etc from my classified land use data at different elevation zones at an interval of 100m. I have DEM of my study area ...
1
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1answer
89 views

Creating Slope from DEM in ArcGIS Desktop so that information is in feet per mile?

I'm trying to get the Time concentration for the ModClark method in Hec-HMS, and one of the variables is Slope in feet per mile. I have a DEM for the sub basin that I've download, the elevation was ...
3
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1answer
3k views

Creating DEM from vector contours using GRASS and R?

I want to convert vector contours to a DEM. From other posts, I wanted to use the Grass r.surf.contours tool. Initially, I converted the vector contour layer to a rasterized contours using the ...
1
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0answers
38 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
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1answer
97 views

Creating DEM from mesh? [duplicate]

I have a mesh ( with points and triangles that define it), and I will need to create a DEM model out of it ( in geotiff format if possible for space consideration, if not, then in ASCII grid format). ...
1
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1answer
69 views

How can I use line vectors to alter my DEM?

I'm trying to use vector lines to change the height of the areas of my DEM that they overlay. They trace rivers, and i'm hoping to assign arbitrarily high values to the rivers so that my least-cost ...
1
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2answers
64 views

How do I combine these two rasters?

I have a raster representing rivers/drainage basins within a terrain: I have a raster DEM of the terrain: In the basin raster, everything in black is 9999. White is nodata. The DEM is obviously a ...
4
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3answers
583 views

Merging one DEM into another to fill in missing data using QGIS?

I have a LiDAR dataset with some missing data right in the middle of my map. I would like to use a 5m DEM to fill in the missing areas. Is there a way in QGIS to merge the two but only use the 5m ...
0
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0answers
84 views

DEM - calculate shortest/easiest path over mountain range [duplicate]

In QGIS, I have a mountain range with a valley on either side (DEM raster file). Is there software or a plugin that allows me to calculate the easiest pathway over the mountain? The answers at Cost ...
1
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1answer
334 views

How do I create a binary mask using Pixel values from a Numpy Array over a certain value (i.e. >1000), in Python [closed]

I would like to create a binary mask using the height values from a Digital Elevation Model, and export this out as a tif. For example, generate a mask for areas over 50m My code so far: from osgeo ...
6
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3answers
2k views

Burning road network into DEM?

Does anyone have any suggestions for burning a road network into a DEM? I have a Python script written up for this executing this in ArcMap, but I would love to hear if anyone knows of any freely ...
-2
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2answers
286 views

Calculating canopy height in ArcGIS Desktop without LiDAR data?

I am currently trying to assess vegetation height for my study area. I am trying to use this guide: http://desktop.arcgis.com/en/arcmap/10.3/manage-data/las-dataset/lidar-solutions-estimating-forest-...
0
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1answer
51 views

Reclassify with attribute

So, I don't really know how to word what I want to ask, but I took a DEM file and did used the raster calculator to select a certain elevation range. After that I reclassified it to separate it into ...
0
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0answers
29 views

Interpretation of digital surface model (DSM) built from s2p tool and XML file

I am new to GIS. I am using s2p stereo pipeline to build Digital Surface Model (DSM.tif) from it. The height of certain point in this DSM.tif is 84 meters, and you can see from the color bar on ...
0
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1answer
53 views

Image not draping over DEM in ArcScene?

I saw Images not draping onto DEM in ArcScene? but it is different from my issue. I have an image with projection: NAD_1983_StatePlane_Oregon_North_FIPS_3601_Feet. I have a DEM and set the base ...
1
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1answer
508 views

Error Message Orthorectifying ASTER Imagery in ArcMap 10 with DEM

I am trying to orthorectify ASTER imagery (VNIR, 15m resolution) in ArcMap using an ASTER DEM that I have downloaded from the GDEM website. The area is in the Andes, there are very high elevation ...
4
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1answer
9k views

Removing pixel values below 0 in Digital Elevation Model in ArcGIS for Desktop?

I made a DEM layer from a .las file (LiDAR). How can I remove the black area which contains negative values? Is it possible to set these values equal zero or null?