Questions tagged [contour]

Contour maps depict spatially-varying values, such as elevation, by means of curves of equal value.

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61 views

Creating line that follows lowest elevation on contour map in QGIS

I have a shapefile of contours that I generated from LiDAR data on QGIS. I'm trying to create a line that follows the lowest point of elevation across the entire map that follows a ditch (it's a long ...
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1answer
51 views

Creating a DEM from irregularly spaced contour lines in QGIS

I'm using QGIS to work with a contour line shapefile with contour lines that are not spaced evenly (e.g. not just 100 meter elevation increase between each line). The increase ranges from a 100 meter ...
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30 views

Problems when importing shapefile with the Blender GIS add on from QGIS: contour lines appear flat

So I'm trying to import a shapefile of contour lines of groundwater isohypses that I have loaded into QGIS and saved separately. I'm actually following the steps of a online tutorial of our department ...
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41 views

LiDAR download - ASC file to QGIS - Rasterize ->Extract -> COntour - Export to Google Earth Pro

I am trying to create a 50cm contour map using QGIS and then export it as KML to Google Earth Pro. When I get to Earth and import the KML file I am left with random red lines around the globe. The ...
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1answer
34 views

Creating Contours from Raster using PyQGIS

I am trying to create contours from a raster layer I have loaded in my QGIS project as below using gdal from qgis.core import QgsProject import processing ## QgsVectorLayer('Coordinate','Layer name','...
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15 views

Using reclassified raster to make contours, contours contain the class value instead of height value

I reclassified my raster to 12 classes and used the contour tool to make contours from there (they are much smoother). The issue is, the contour lines no longer contain the raster height, they ...
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1answer
54 views

Merge Contour Boundary for Polygons QGIS

Hoping this is fairly simple but haven't been able to find much online. I am trying to create some elevation polygons from a DEM model. Right now I am getting this after getting the contours, ...
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33 views

Adding labels to contours created with the rendering option of rasters in QGIS 3.16

Is it possible to add labels to raster contours created using this option in the "Render Type" under "Raster symbology"?
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23 views

Convert contour shapefile to MicroStation dgn file in QGIS

I have a contour shapefile in QGIS with labels on (elevations for labels). I am able to convert it to MicroStation dgn file but the elevation labels of the contour shapefile are not converted with the ...
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121 views

XYZ LiDAR data to contours with QGIS

I need to prepare a 1m contour map for an area with LiDAR data (XYZ files, in a 1m grid). The files are a little large and there are 54 of them. I merged the files to a single XYZ file (which turned ...
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15 views

Plotting contour map for geodetic data

I need to plot contour plot for a geodetic dataset.I have data for 94 locations of New Zealand. I have been able to generate a map a New Zealand using cartopy library of Python. I have used python's ...
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1answer
37 views

Area commanded from given point

I want to define the area below a contour that slopes at a particular angle (say -0.05%) from a particular point, for many points. I have a DEM, and can compute contours at a particular level (say 200 ...
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19 views

Plotting contours for geodetic data.(in Python)

I need to plot contour plot for a geodetic dataset, but I have data for 15 locations of New Zealand. I have been able to generate a map a New Zealand using cartopy library of Python, but I am not sure ...
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1answer
47 views

QGIS: Creating contours at a certain elevation from DEM that match a value from a polygon layer

Trying to create contours from a 1m DEM at certain levels only when the contours fall inside a polygon with an field containing the desired contour elevation value. See images below. For example in ...
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27 views

GDAL warp & GDAL contour inconsistent results

I am creating 2 output contours based on the same input DEM, one is clipped to a smaller grid feature (green line) while the other is clipped to a larger irregular polygon (blue line). The problem is ...
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1answer
52 views

Connecting contours in ArcGIS

I am using ArcGlobe. I created contour lines using the contour tool, but some of them are not connected and are just fragments of lines, is there any tool that could connect these lines?
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1answer
48 views

FME SherbandGeneralizer - estimate time for “Optimizing Memory usage”

I have a workspace with a pointcloud of 240.000.000 points as input, goal is generalized countour lines, that do not intersect each other. The workspace mainly consists of (cp. screenshot) ...
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49 views

Deleting holes of contour polygon in QGIS

I'm trying to create hypsometric areas from a DEM. My current workflow in QGIS is: Extracting contours with SAGA, as I need contours from specific elevations (250, 500, 1000...) and not just every x ...
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35 views

Contour polygon created at different intervals than the desired interval

I have a DEM in WGS84 coordinates with a minimum elevation of 2083 meters and a maximum elevation of 3000 meters. I then used the Contour tool in ArcGIS 10.7 to create contour polygons at an interval ...
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26 views

How to export QGIS Contours to be compatible with 12D Software

I have processed my aerial drone survey images with Ground Control Points using AgiSoft. My accuracy and results were good. I have exported the DEM into QGIS and generated the Contours with labels etc....
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1answer
28 views

Merge features in same feature class on same attribute

I have a feature class of lake contours. This feature class is the result of multiple lakes' contour data being appended into my Contours feature class. I now have over 300,000 lines of contours, and ...
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1answer
46 views

Contour lines are somewhat square-ish?

I am exporting contour lines from a raster file which was obtained by clipping a shapefile to a much larger raster file. The contour lines obtained are square-ish as in the second image below. My ...
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62 views

Having trouble with the Heatmap's (Kernel Density Estimation-KDE) interpretation in QGIS 3.10

i wanted to generate a density/concentration map of a parameter, in this case Carbon percentage in a water sample. The dataset in csv file looks like these : So, I imported the csv file then plotted ...
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24 views

Speed up colouring of contour lines by creating new layer?

Related to my previous question: Colouring contour lines differently when they are inside polygons of another layer I would like to create a new layer based upon the result of the geometry generator ...
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1answer
118 views

Colouring contour lines differently when they are inside polygons of another layer

I'm a complete noob to QGIS. I am working with New Zealand Topo 1:50.000 data from LINZ. I have snow polygons and over them contour lines. Where the lines cross the polygons I want to change the ...
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47 views

Writing “m” after contour line label numbers

does anyone know what is the expression to display the letter "m" after contour line numbers in Arcgis? I want it to be like this. I believe is in this window wizard, just don't know what ...
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48 views

Invalid geometry type after clipping

I have two files (.xyz) with point data from a terrain. I'd like to create contour lines of said terrain but in a smaller area (limited by a polygon). After importing the points in two layers, I merge ...
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1answer
55 views

Change Stroke Width of a Polygon PyQGIS

I'm trying to set the Width of the lake's contours to zero or change the color to light blue, since the I dont want to see the black outline. The vector file is a Polygon (MultiPolygon) named vlayer2 ...
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37 views

Raster to Lines fails (R)

I have the following set of images where a set of 8-neighbor contiguous pixels are outlined in each image, representing a line. The images are distinct, but the lines generally run from left to right. ...
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2answers
140 views

Create contours based on text attribute of point data (isogloss map)

I am trying to make an isogloss map in QGIS to map dialect differences. I have made a point shapefile in which each point represents a place, and the different pronunciations are put in the attribute ...
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46 views

QGIS 3.10 create DEM from height contours - the maximum height values of the grid to do not match the maximum height values of the contours

I have created a DEM using contours spaced 10 metres via QGIS grid ITN interpolation method based on height (metres) cell size 10 pixels/metres in QGIS, and another grid of 5 pixels cell size. When I ...
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38 views

How to display contour labels within QGIS using Maptiler

How can I display contour labels within QGIS using the Maptiler plugin? The contour elevation (height) displays 440m in the Identify Result pannel. Can the Layer Properties be reconfigured to display ...
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1answer
43 views

Does anyone have had a similar problem regarding extracting contours?

I have been working on QGIS 3.10, I am using DEMs files that come originally from Lidar data, so they are large files with high resolution. I have been trying to create contours using the: Raster, ...
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1answer
156 views

Export the contour lines of the relief from OSM

My goal is to display the contour lines of the relief in Google Earth. So, I would like to export from OpenStreetMap the contour lines of the relief of a region. My goal is to download the data as a ...
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27 views

Blank Polygon issue using QGIS Contour Plugin

I am using QGIS with Contour plugin, want to generate filled contour polygons with user selected contour levels. However there are some errors showing blank polygons. Is it bug or is there any way to ...
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1answer
22 views

No Option to 'Extract' under 'Raster' tab

So I'm running an earlier version of QGIS (3.4.6, as it is supposed to be more stable I'm told) for a Field Geology course, however after installing it and adding DEM data I am unable to 'Extract>...
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1answer
154 views

Changing blending of contour label to multiply

I would like to label my maps like these in QGIS (image created using Photoshop): Image of contour label being shown on the contour lines with with white halo and then the colored raster layer above ...
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38 views

Draw ellipse based on values within an attribute table

I would like to be able to draw and ellipse on a map based on values within an attributes table. At the moment I have 6 transects at a site with values based on IQI (Infaunal Quality Index) values; ...
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2answers
91 views

Creating point attribute distribution map in QGIS

I'm working with multiple species distribution data and am looking at creating what amount to density distribution maps of those species. I have a small number of site locations (18) and only 10 ...
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45 views

Hiding optional outputs in Model Builder?

I am creating a model in ArcGIS Desktop version 10.7.1 that uses the "Topo to Raster" tool to convert contours (line shapefile) to a raster. The contours are actually representing lines of equal ...
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0answers
69 views

QGIS create contour from DEM

I have created a DEM from points using the raster interpolation method, the TIN function, based on elevation of each point. However, when I try to create a contourline, the results show the contours ...
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1answer
75 views

Styling a contour line to indicate the direction of elevation

I've just got a slippy map set-up using Mapnik to render OpenStreetMap data. I've loaded SRTM elevation data following the PostGIS steps here and can now see contour lines on the map. I'm trying to ...
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2answers
71 views

Splitting GEOTiff of Mars

I am trying to make a map of a terraformed Mars in QGIS and as a part of that, I need to convert the Mars MOLA DEM into contour lines at an interval of 100m. However, the file is too big for QGIS to ...
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1answer
76 views

Getting elevation data from DEM

I'm trying to extract elevation data from a DEM file but I can't make it work. I want to extract contour lines from a given area, and label those lines with the proper elevation value. The problem I'...
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1answer
100 views

How to extract contours from .jp2 DEM dataset?

This will be a little long-winded but I'm including all information I consider relevant. Problem: I have received a data set from a municipality that is a 3-layer LiDAR JP2 DEM and need to extract ...
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19 views

Add buildings contours to DGM for hydraulic analysis [duplicate]

I use Hydrology Terrain Analysis Tools in QGIS/ArcGis. Now I try to add some building contours to my DEM. I got building Data (Polygons) and a Raster DEM. Finally I want the buildings added to my DEM, ...
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1answer
100 views

QGIS Wrong “ELEV” values from contour

My problem is that I'm trying to extract contours and elevations from a DEM map. Everything else looks fine, but I think that the "ELEV" values I'm getting are not the real elevations, maybe I'm ...
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32 views

Cannot add Contour to layers

I am brand new to QGIS as my uni has shut down but we still need to do our coursework they have asked up to make a bathymetry map on QGIS. It is a very simple map of sounding data we have taken and ...
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1answer
105 views

Conditional formatting QGIS Legend

I use QGIS to create surface plots for measurements made in the field. I use the contour plugin. I usually create ~50 contours in order to make a smooth surface. When I use print composer, I generally ...
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73 views

Using of ContourGenerate in PyQGIS

Can anyone help explain me how to use the ContourGenerate method of GDAL. The official documentation states two sets of arguments for the method, with one being ContourGenerate ( **args, ***kwargs ) ...

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