Questions tagged [elevation]

The vertical distance of a point or object above or below a reference surface or datum (generally mean sea level).

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1answer
107 views

Determining elevation of a point from a DEM in QGIS?

I have created a series of DEMs that layercake on top of each other. I would like to be able to lookup a coordinate and get the elevation that has already been interpolated. The goal is to ...
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2answers
297 views

Source of Contour Lines for QGIS

I am planning to go on multiple days hike and used Wikiloc to download GPX tracks. We will use a GPS for our navigation but I always want a printed map as a backup. Maps for that area are notoriously ...
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1answer
66 views

Using UK Government Data in QGIS?

I've downloaded some .asc files from the UK Government. They are 1m resolution LIDAR tiles. Apparently. When I load them into QGIS, they appear with the nice thumbnails and everything. But I get ...
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68 views

Extracting raster values to point feature class failing in ArcMap?

I need to extract values to point features from Mosaic dataset made out of DEMs (Whole world SRTM) . My feature class has 18,000,00 points. When I ran the below tools, only <20K points receive ...
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1answer
287 views

Getting correct elevation from hgt file [closed]

When reading SRTM3 data from a .hgt file I get the wrong elevation of a specific latitude longitude and I can't see why. Maybe someone can see the problem ? My coordinate is near Lissabon in the sea ...
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2answers
45 views

DEM's from Baja, Mexico [closed]

I need to extend my digital elevation map (10m or 30m will do) into Baja from southern CA.
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2answers
306 views

Calculate pixel value in arcmap

I want to change pixel values of elevation data. I want to change values meter to feet. So i need to multiply pixel values with 3.2808. How can i do that in arcmap?
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1answer
40 views

Identifying the greatest value point within each polygon

I have a series of polygons (4,000) and a series of points that exist on the perimeter of each polygon (3 to 5). The points refer to the elevation value which has previously been extracted from a DEM ...
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2answers
59 views

Elevation Data in form of a database or colored Map

I am new to the GIS Topic and I hope someone can help me in the following. I am looking for elevation data for the whole world in the form of a database (Latitude; Longitude; Elevation(Level over ...
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156 views

QGIS - Lookup elevation or slope from geoTIFF from a series of lat/lon values

I have a geoTIFF file (pretty large) covering a good chunk of Spain around Almeria. I got it from the EU-DEM v1.1 data (25m resolution), freely available in which I have a route in lat/long and I want ...
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2answers
531 views

Plotting and analyzing extracted elevation data in R?

I have a shapefile of county boundaries for New York state and elevation data downloaded through the elevatr package. library(elevatr) library(raster) library(sf) library(USAboundaries) counties <...
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55 views

Editing elevation in ArcGIS Desktop?

I have a raster layer that covers a large area (three cities). When I load the raster layer into a 3D visualizer, there are multiple areas with a drastic change in the slope rather than a gentle ...
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1answer
93 views

How do I use a Simple Feature Collection (sfc) from the sf package with the elevatr package to load elevation data?

I'm trying to load elevation data from AWS using the elevatr package, with a region defined as a Simple Features Collection from the sf package. Here's a simple example: library(elevatr) library(sf) ...
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3answers
297 views

Latitude above and below the surface of the Earth

I know that Geodetic Latitude is measured with respect to the normal at a point on the surface of the reference ellipsoid. But what about points above and below the surface? Do they follow a ...
2
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1answer
222 views

Reprojecting XYZ coordinates in Python whilst keeping Z coordinate constant

When doing a reprojection from a projected coordinate system (e.g. EPSG:28992) to a geographic coordinate system (e.g. EPSG:4326), the Z coordinate gets an offset of 45 meters. The Z coordinates of ...
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1answer
134 views

Elevation API: Same coordinates, different elevation result

I'm using google maps elevation API, but while asking a single request(single coordinates) and a multi-request(many coordinates), I'm getting different elevation result of the same latitude and ...
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2answers
73 views

Expression in field calculator to populate a field with the same attributes as other field

I am just after a super simple expression to copy the attributes of one field directly into a new field with a different name - to export to AutoCAD with Z height data.
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1answer
77 views

Can QGIS produce a Stage Storage Plan?

I work for an engineering firm, and my question to the forum is: Can QGIS produce a stage storage plan for multiple drainage basins? I am attaching an image of what I am talking about. Currently, we ...
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0answers
76 views

Selecting raster pixels based on dem range

I have two raster layers that are equal extent and resolution: one that is qualified as nonforest tree cover that is made up of pixels with either the value of 1 or NA, and one DEM. What I am hoping ...
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0answers
54 views

Converting Surface Model to Elevation Model?

Is there a way to convert a digital surface model (DSM) to a digital elevation model (DEM) in QGIS? Surface models contain lots of noise (e.g. trees, buildings) when I only want to show the ground. ...
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156 views

Locate roads that are close to steep slopes which risks landslides

I've a query, I'm trying to locate all the roads which are basically at risk of erosion (landslide?) when it's raining heavily for a municipality. What I have to work with is this: A shape layer ...
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1answer
192 views

Getting elevation from polyline feature using QGIS?

I have imported contour lines from AutoCAD DXF file. I've 3D geometry. Í would like to add a new column to the attribute table of the contour lines. In th field calculator I user the following ...
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1answer
1k views

Creating Elevation Profile from Line Shapefile of Contours using QGIS?

I have a line shapefile that contains contour lines. The attribute table of the shapefile has a field that gives the elevation of each line. I would like to draw a line across the contours and get an ...
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1answer
74 views

Elevation shading of linear feature compared to surrounding ground level in QGIS

I have a digital elevation model (DEM - geoTIFF) in QGIS 3.2. There is a linear feature (earth bund/wall) in the DEM that I would like to shade/colour based on its elevation above the surrounding ...
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139 views

Generate XYZ coordinates of DEM mesh/grid

Is there a way to generate a wire grid of plain text XYZ coordinates starting and ending points for each wire segment? I want to generate them from a digital elevation model. Preferably with gdal/qgis ...
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0answers
197 views

How to change the vertical datum of a geotiff DEM

I am trying to do some change detection between SFM derived DEM products, but the DEM i would like to use as my base elevation (and one other) is in NAD83, the remainder are WGS84. I would like to ...
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46 views

GeoTIFF software generation

I have some data about the height of a set of points (for example, from the Google Elevation API). There is a task to save this data in GeoTIFF format, then to use in osgEarth (GDAL). How can this be ...
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1answer
161 views

Trimble 7X GNSS point Z returns negative elevations

I have a newly acquired Trimble 7X (with a centimeter kit). I collected a point in an area with a clear view of the sky. The accuracy indicator showed 1" accuracy and post processing and a ...
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0answers
78 views

QGIS .adf file saved as GTiff changes elevations

I have got two .adf DEMs which I need in GTiff format so they can be merged. When I 'Save As' the layer as a GTiff, the resulting output has elevations which are inconsistent with the original .adf ...
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1answer
193 views

Calculating floodplain for river section using DEM only in ArcGIS Desktop?

I'm looking to create areas where water might go when a river floods its banks. I have a pretty good resolution DEM (5ft^2 for each "square"). I'm not looking for anything super accurate or precise ...
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1answer
163 views

Extracting only elevation data from NASA's GLAS Satellite LiDAR to create raster DEM?

I'm trying to open data downloaded from NASA's Earthdata site in ArcGIS 10.4.1. Specifically I'm trying to open "GLAS/ICESat L2 Global Land Surface Altimetry Data (HDF5) V034" (Image below, ...
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1answer
148 views

Use DEM elevation attributes in vector polygon?

I am modeling glacier retreat scatching polygons on DEM surface trying to come out with 3D scatch. Is it possible to adjust "height" of polygon to follow elevation of DEM surface (eg. glacier height ...
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1answer
83 views

Generating a buffer of a vector line based on raster values where the vector intersects a raster

I am trying to figure out how to buffer a vector shapefile with a variable distance (in QGIS). However, the variable distance needs to be dependent on the value of a raster (DEM) where that vector ...
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0answers
192 views

GDAL merge of DEM data resulting in large black tiles, elevation min/max problem?

I am new to QGIS (former Arc user) and having trouble with the raster merge tool. I am merging 7 tiles of SRTM arc 1 data to cover a province in eastern Ecuador. Data is resulting in large areas of ...
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1answer
71 views

Getting elevation profile graphs along parallel interpolate lines using ArcGIS 3D Analyst? [closed]

I'm new to ArcGIS. I have used "Interpolate Line" tool in the 3D Analyst Toolbox to get an elevation profile graph. How can I create several parallel interpolate lines, maybe with specific distance ...
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1answer
46 views

Just need a lo-res & 8-bit depth elevation map either real or fictional (BMP?)

I am a software developer working on a strategy game in my spare time as a hobby. I still have very little knowledge of and experience with Geographic Information Systems and the different file ...
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1answer
175 views

Altitude isoline vector tiles?

Is there a service that can provide altitude isoline as vector tiles? I've seen that there are some posts on how to convert elevation tiles (raster DEM) with python or javascript applying some image ...
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0answers
60 views

Creating a polygon that shows the specific elevation above a river using a DEM

My goal is to determine the possible area covered by interpreted Tertiary drainages. To keep my example simple, I have a DEM and a River polyline. I would like to see the area a polygon (or raster) ...
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1answer
112 views

Using groundwater data in ArcMap? [closed]

I have raw data in the form of groundwater levels collected regularly over a couple of years. The values are collected in an excel file together with xy coordinates for the water wells (of which there ...
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0answers
52 views

ArcGIS Elevation and Z Coordinate

I have standalone application (ArcObjects C# 10.3) uses axSceneControl, I'm trying to get a mouse click point: private void M_axSceneControl_MouseDown(object sender, ...
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1answer
27 views

Two raster classes according to cut-off elevation using ArcPy?

I've defined a python function to take input raster and elevation and output path. The function should return raster with two values 0 for elevation equal to and greater than given elevation and 1 for ...
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1answer
391 views

QGIS - Lakes - Change Polygon Z values, using Single Field Value

I want to change all the elevation of the polygons of a shapefile using the field value ELEV from each polygon. So each vertex of each polygons as all the same Z (elevation). Anyone knows how to do ...
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1answer
108 views

Hydrological conditioning using stream vector in GRASS?

I would like to make an hydrological conditioning of a DEM using an available stream network in vector form. I know r.hydrodem but it doesn't allow to use the stream vector. I need something to burn ...
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0answers
22 views

data.frame and get_elev_points. Error in locations$elevation[idx_s[i]:idx_e[i]] <- unlist(resp$height) : replacement has length zero

I am trying to use the function get_elevation_points in a data frame, but keep getting the same error: > #get the API key : et an API Key from https://mapzen.com/developers. Since elevatr will ...
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0answers
483 views

DWG/DXF conversion to DEM file

I have got a detailed CAD drawing (DWG format) showing a house plan and topographic survey. I want to use the heights from the topo survey to create a digital elevation map in QGIS. I have tried a ...
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0answers
172 views

Co-registration of two DEM raster

I have 2 different elevation files, a ALOS GDSM elevation set & a DSM extracted from Corona imagery. Since the Corona file has some inevitable offsets (mainly in z, non-systematic across the area ...
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1answer
140 views

How can get correct elevation values from Digital elevation models

I am a bit new to spatial data analysis. I am trying to analyse elevation data for a coastal (almost flat) city with the highest elevation of about 30m. I have DEMs from ASTER, SRTM, and a DSM from ...
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2answers
35 views

elevation difference along the border of two categories GRASS

Consider the following raster with two categories and a DEM (numeric raster), I'd like to compute the elevation difference along the border (closest pixel) of those two categories, it doesn't matter ...
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0answers
49 views

Checking and enforcing downstream Z constraint for synthetic streams?

Assume I've delineated planar (X, Y) stream breaklines to use them for enforcement of bare ground DEM derivation from high density lidar data. The stream features are in a Z and M enabled polyline ...
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1answer
55 views

Can I created a DEM or digital surface model with high resolution image

I have VHR imagery, 5 cm pixel, and I want to create a DEM but this image has high trees and when I take my model I cant take a real elevation because DEM is not the height of the terrain. Could I ...