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

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1answer
184 views

DEM Processing in ArcMap

I have a question regarding DEM. I have downloaded SRTM DEM 30 m and I did a mosaic for the data using Mosaic tools in Arcmap to a Mosaic to a new raster. However, I got a DEM raster with values of 0-...
2
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0answers
55 views

Fixing undesirable lines between tiles from SRTM contour line extraction?

I'm trying to make a South American topography map based on SRTM data on QGIS. The problem is a visual one. If the topography contours are extracted from individual SRTM tiles, it results a little ...
4
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1answer
252 views

Converting LAS 1.4 to 1.2

LIDAR files were released for major part of Slovenia few months back in zlas format. Decompressed LAS format is 1.4 version. I have tried many options how to generate DEMs and had some success in ...
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2answers
177 views

Using DTM slope map to find shortest route between two locations using QGIS?

I've got two locations, A and B, and a DTM covering the region between A and B. Say I want to drive from A to B. I want the shortest route possible, but avoiding regions with slopes higher than, let's ...
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2answers
163 views

Selecting Specific Elevation Areas Contiguous to the Coastline for Coastal Flood Mapping

This is less a problem than an inquiry into a better way of doing something. I am curious how people might go about selecting, say, all areas less than or equal to 10 feet (from a DEM) that are ...
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2answers
582 views

How do I find the slope of road segments with point elevation data of the same linear path

I'm currently working on a project to calculate road grade along roughly 30 miles of highway. I need to isolate and portray all sections of road with more than a 5 percent grade; in hopes of finding ...
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2answers
67 views

How do I generate grid square polygons from a 5m DTM file?

For my dissertation I have collected point features as coordinates and want to relate their distribution around a lake to elevation to see if there is any pattern/relationship between them. I have ...
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1answer
111 views

How to create a series of cross sections in arcgis 10.2?

My ouput should be a series of cross-sections (10 meters apart) along a center line of a river. The input data is a raster data set with elevation values. Can I also automatically generate the lines ...
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1answer
75 views

In ArcGIS 10.x, how do I select features of a point shapefile whose z values are above or below the elevations in a DEM?

I have a multi-point shapefile representing earthquake hypocenters (containing depth values) and I have a DEM raster representing an underground surface (the top of the PreCambrian basement). I want ...
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1answer
37 views

How to match river direction with DTM?

I have rivers that some times they do not match their real direction based on the DTM, and they need to be flipped. Is there any way to automatically match river direction based on the DTM in ArcGIS ...
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0answers
43 views

identify and calculate area of valleys

I have a shape file (points) that contains the coordinates of a number of cities in a mountainous area (valleys separated by mountain ridges), and a DEM of the area. I would like to calculate the ...
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1answer
110 views

Finding area of DEM raster clip?

I have a DEM layer in ArcMap 10.2 which I then clipped to fit a large shapefile. I'm trying to find the area of the new DEM shape using the Image Analysis tools, specifically the Mensuration tools. I ...
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0answers
51 views

3D model to DEM, maintain volume?

Bit of a challenge here which I've been grappling with for some time. I'll explain my full work flow so you can reproduce if needed. I'm creating virtual landscapes in Google SketchUp which I ...
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1answer
345 views

SRTM vs Google Earth Pro elevation data

I am working on elevation data for an area in Sudan. Between Google Earth Pro and SRTM elevation data, which one is more reliable?
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0answers
44 views

Calculating aspect in flat areas in ASTER DEM with ArcGIS for Desktop?

I have an analyzed aspect surface from ASTER DEM 30m resolution in ArcGIS 10.2. But it shows many aspects in flat area.Normaly it must calculate this are as flat (-1). How can I resolve this problem?
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0answers
90 views

Making DEM and Landsat Image Coincide in ArcMap?

I have a DEM with these properties: Spatial Reference: GCS_WGS_1984 Angular Unit: Degree (0.0174532925199433) Datum: D_WGS_1984 Raster Information: Columns and Rows: 3051, 2426 Cell size: 0....
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0answers
86 views

Creating a DTM from Contours, via the command line or Python

I am looking to create a gridded DTM/DEM (Digital Terrain/Elevation Model) or TIN (Triangulated Irregular Network) from a set of contours. There are a number of similar questions on both this site ...
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1answer
25 views

Strange Vertical Mapper issue

While using the Mapinfo 7.0+ Vertical Mapper 3.0 on a Windows 8.1, I am facing the following issue: After adding a DTM (in .grd format), which is displayed perfectly, I am trying to use the Grid Info ...
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71 views

erdas LPS : Load Z values from a DEM?

I'm working on a photogrametric project with erdas LPS version 2013. I succeed in taking several ground control points (x and y values). However, i can't extract and load Z values from my raster DEM ...
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0answers
25 views

Orfeo Toolbox DEM download error

I have been trying to use the following part of the Orfeo Toolbox to download DEM data from usgs. I have been passing it a geotiff image as the reference and am receiving the following error: 2015 ...
2
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1answer
2k views

How to extract DEM files from google Earth/Map for surfer?

I will need to do a 3D representation of a terrain and I heard surfer is ideal, but then I do not have a DEM file of the region, I know Google Earth and Map could help, but I do not know how? If there ...
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3answers
295 views

Adding two raster datasets that overlap while maintaining extent of larger raster dataset?

I am using ArcMAP 10.0 How do I add two raster datasets that overlap while maintaining the extent of the larger raster dataset. I have thought of adding zero values to the smaller raster to then be ...
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2answers
78 views

programmatic DEM downloads similar to landsat-util

I recently discovered landsat-util, and was wondering if there was an equivalent command-line application for global elevation data, (for data around 1 arcsecond resolution, preferably geotiff) or if ...
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0answers
127 views

How to make DEM raster in Google Sketchup?

I would like to make DEM in google sketchup, later add 3D buildings and finally convert this file to raster. Afterwards, I want to import this raster to GRASS GIS to make solar maps. It is possible to ...
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0answers
68 views

Las tools vs Geocue for LAS1.3 processing [closed]

I am a user of terra solid products. I have las1.3 data set which i need to perform whole processing in 1.3 version. (I need to supply WDP informtaion and classified las dataset as well. So I afraid, ...
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12 views

Where to find free DSM data of Switzerland (Ticino)? [duplicate]

I am working on a sonification project. My aim is to sonify data coming from a delimited area in Switzerland. I also would like to print out a 3d map of that region based on that data. Problem is : ...
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0answers
70 views

How to extract area information from a raster based on a DEM or contour lines

I have a raster representing the distribution of a specific land cover type - the raster values are 1 for where the land cover type is present and 0 where it isn't. I also have a DEM with 5m ...
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4answers
234 views

How can Identify highs on a DEM?

I have a DEM and I want to find each hill and create a polygon for its area, effectively the out closed contour that encloses the hill. I can do this visually but I'm about to work on a larger area so ...
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0answers
41 views

Mosaic DEM has large pixel when displayed in ArcMap?

I created a mosaic dataset in ArcMap 10.2 from tiles of ASTER DEM's at 30m resolution. I am attaching the image of what my export looks like. You can see that there are extremely large, alternating ...
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2answers
180 views

How to export a polygon based on elevations using a DTM or a DEM

I have a LiDAR generated DTM and a DEM (accurate to 10x10 feet). I am trying to export a polygon within a boundary which includes all elevations below a specific number. Seems like this should be ...
2
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1answer
63 views

How do I find out the sea levels?

I have following elevation data of a region (the higher the altitude, the brigher the points): How can I find out, which areas are filled by water, and which not? Can I assume that if the ...
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1answer
79 views

Is there a way to Alter Elevation Values of Pixles of a DEM based on BM and Control point elevation from actual Field survey?

We have got a quick bird DEM of our site. After getting actual on ground elevation values with a differential GPS device, we have found that there is a difference of average 12 feet between DEM and ...
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54 views

Resampling and snapping DEM to match a second raster

I have a DEM that is derived from a 50K map (provided by Geobase Canada), the resolution indicates it is 23.19156058m per cell (raster name DEM_50K). I need to resample this DEM to a 100m cell size (...
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1answer
41 views

Dtm format save only heights

I need dtm format that store only heights and scaling and left up position for saving storage I glad to know if any stadard save heights that way
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2answers
56 views

Equidistance on line contour from DEM

I am using a SRTM 30 meters for slope and elevation. When i'm using this 30x30 rasters to generate contours i set a 30m equidistance for contour, and the results are ok. Now i'm wondering if it's ...
3
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1answer
91 views

Whitebox GAT not starting under Windows 10 - General JAVA or Whitebox problem?

I am currently running the DEM preprocessing on a relatively large (50000 km2 at 30 m resolution) and steep DEM. The objective is to extract the stream network and some morphologic attributes (e.g., ...
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2answers
67 views

Update raster pixels on a DEM

I have a DEM in the form of a raster that I would like to update in certain locations. Ideally, I'd like to be able to create a separate polygon or point shapefile with the values, in the correct ...
1
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1answer
19 views

In QGIS, add to existing dem tiles and expand corresponding contour coverage within a project

In my first QGIS project I have dozens of digitized layers that have spread beyond the contour and dem tile area that I started with. Please recommend how to safely expand or replace the dem and ...
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0answers
26 views

Apply mask on ERDAS LPS

I am currently working on my final year dissertation and most of it is done on LPS. I am using Cartosat-1 and ALOS PRISM imagery to create DTMs for an area that is located on a peninsula. The problem ...
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0answers
28 views

Combining multiple DEMs into one file geodatabase

I have multiple file geodatabases (approximately 240) each contain a DEM. My issue is taking the DEM from each and putting it into a single file geodatabase without alot of mind numbing work. ...
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0answers
65 views

how to define threshold value in r.stream.extract

I want to generate streams using r.stream.extract. on what basis we have to define the threshold value. I am using aster dem with 30m posting.Also i want to know the minimum stream length to be ...
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0answers
46 views

Quantifying amount of sunlight falling in a region

I am trying to objectively quantify or provide some form of indication that could point toward the amount of sunlight Anyone knows if there are any datasets (either instrumental or remotely sensed ...
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1answer
175 views

How to run a tool from Whitebox GAT in ArcGIS?

I have a series of tools that I need to run in ArcGIS to hydrologically condition my DEM, but the first step in this process is running the Breach Depressions tool from Whitebox GAT (I have found that ...
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0answers
17 views

Extracting Elevation (DEM) from air photos using open source software? [duplicate]

I have a few pairs of stereo air photos and I want to extract a DEM from them. I think that is possible using PCI (OrthoEngine), but I would like to do it using Open Source (or at least free) ...
2
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0answers
129 views

High Resolution Terrain Data for the Philippines

Where can i download Philippines terrain data that is better than the 30 m ASTER global dataset?
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2answers
120 views

Topographical Elevations for Central Africa and Cameroon

I am using QGIS and I have been faced with the problem of topographical maps. From searching online I could only find data for the United States. Google maps offers elevation contours, however I am ...
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0answers
31 views

Is there an existing tool or plugin to automate the elevation versus volume relationship of a dem within a user provided polygon

I often need to obtain the elevation versus volume data for a proposed basin site but have not found a truly automated solution. I would simply like to create a bounding contour polygon of the DEM ...
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2answers
392 views

Masking out places with elevation below 5 m from a DEM

I have a DEM of a study region; I want to modify the DEM in order to reflect the coastline outlook when the sea level was 5 meters higher than today. What I have done so far is to use 'Raster ...
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0answers
33 views

ASTER data error causing “bumps” in elevation

I am working in ArcScene (10.1) with some 30m resolution ASTER data from Indonesia, and am getting anomalous "bumps" in elevation in my study area. In google earth it is not there, and I know from ...
3
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1answer
68 views

Simplify / generalization of flow lines

I'm trying to make a model of surface runoff of rain water. I'm using GRASS GIS function r.flow, which generates nice smooth lines of runoff. What I need is edit these flowlines someway to avoid ...