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

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426 views

Extraction of contour lines starting from 0 elevation

I need your help regarding extraction of contour lines in QGIS. I am new to QGIS (in GIS actually). I followed the tutorials on extracting contour lines from DEM (which I downloaded from cgiar.srtm) ...
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18 views

Adding z values to contours without attribute data

I have a set of contour lines with 5 meter interval which doesn't have any height set in the attribute data. Now I'd like to assign (preferably automatic) z values to these contours since I want to ...
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0answers
36 views

How do I calculate kernel density using cases and controls in QGIS?

I have a dataset with approx 1250 geolocated points - approx 150 are cases of a disease and the rest are controls. My area of interest is around 20km by 20km with wide variation in population density. ...
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38 views

Acquiring Digital Elevation Models for Argentina from commercial providers

I'm interested in obtaining Digital Elevation Models for areas in the 20,000 acre range, as I use them to create contour maps for agriculture. The USGS Earth Explorer has a wonderful free DEM ...
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38 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 ...
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221 views

Relationship between contour interval and spatial resolution of a generated DEM

If I have contour lines with interval say 10, 5, or 2 (etc.), and I generated a DEM from them, what is the relationship between between the contour interval and the resolution of the DEM? Irrespective ...
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1answer
737 views

Creating 3D terrain/model from contour lines, preferably using Open Source GIS?

I am looking to create 3D terrain from a contour map that I have (originally inside a PDF). The contour lines are able to be viewed as paths in Adobe Illustrator. There are two types of lines: 7m and ...
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159 views

Generate contour lines for big DEMs and import into PostGis

I've downloaded the SRTM DEM files for most of Europe, from both 3arc_v4.1 and 1arc_v3 versions. The first comes in 5x5 degrees tiles, the latter in 1x1. I can stitch them together with gdalbuildvrt ...
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121 views

How to make label show up on contour vector in QGIS? [closed]

I'm new to QGIS (version 2.6.0). I think my question should be easy to solve but I still get stuck at making labels show up on contour lines. These lines were generated from extracting raster (asc ...
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174 views

Whats the best way to create bathymetric contour lines?

I have a raster dataset with both Topographic and Bathymetric stored in it. What is the best way to create exact contours of the lake-bed? This becomes tricky when I want to make the contour for depth ...
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357 views

Best method to convert CSV file of lat/lon and depth data to bathymetry polygon?

I'm trying to create bathymetry polygons based on lat/long and depth data. I have tried several methods and the resulting polygons are clunky. Make XY Event Layer-->Copy Features--> Project--> ...
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105 views

Applying depth to Shapefile

Apologies if this question has been answered before. I'm digitizing a historic coastline and would like to add a single depth figure to it in order to merge it with a current contour model. Is there ...
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770 views

Contour Lines Raster Extraction

I've been playing with Mapbox's blog post about converting heat maps to contour lines, and I'm stuck at the extraction part of this process. I used the CSV plugin to create a vector layer of points, ...
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1answer
165 views

Computing altitude from contour table - slow ST_Dwithin query

I am using PostgreSQL 9.2/PostGIS 2.0. I have a table of house addresses and a table of contour lines which are as follows: address_list house_id | geom (point, 4283) ---------+--------- 1 | ...
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1answer
792 views

Help with technique to create contours from ASTER DEM in Phnom Penh, Cambodia

I have the ASTER version 2 DEM of Cambodia. I want to use it to create 1m contours of Phnom Penh, Cambodia. If anyone has this already please let me know. Now, onto the problems: I am using ArcGIS ...
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244 views

How to draw contour line between certain elevation range?

I have a raster and I want to draw contour lines just between certain elevation range. For example I want to draw contour lines between elevation 700 (m) and 1000 (m) with the interval of 10. So there ...
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1answer
1k views

How to extract elevation information from contour lines?

I'm working with OS windows 7 and using ArcGIS 10.2 and I have a point shape, which I must extract elevation for every point in it but the only useful data is a contour line shape. Not sure if it's ...
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155 views

Contours from DEM with human features

I am rather new at GIS and I would like to have some guidance on what follows. I have some DEMs derived from LiDAR data. These DEMs contain building and other human features (e.g., roads). I was ...
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291 views

How to make traffic time contour map in ArcMap?

I want to make travel time contour map which shows the area people can go from an origin (e.g. downtown, airport) within certain time interval. I have a roadway linear shapefile with the information ...
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1answer
48 views

General guidelines for topographic contour to DEM conversion?

It seems that many different DEM resolutions (10m, 30m, 100m) could be created from a contour map (with, for instance 50m elevation changes marked), but of course some of the resulting DEMs will be ...
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1answer
37 views

QGIS - how to see the minimum and maximum elevations in contour layer

I am using QGIS 2.12 on a Macbook Pro running OS X Yosemite 10.10.5. I have a contour layer representing elevations. How can I find what the maximum and minimum elevation values in the layer?
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1answer
282 views

Convert .xyz to contours?

Can anyone help me convert .xyz file to a contours? I have recieved some .xyz files from the local council and am hoping to turn them into a terrain for 3d modelling. I have tried the ASCII to feature ...
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2answers
173 views

Where to find the “contours from points” model in QGIS 2.6?

I can't find the example model "contours from points" in QGIS 2.6. Is there another tool for creating contours from points, besides the QGIS Contour plugin?
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128 views

Contour of single feature on QGIS

I'm trying to extract one single contour line at given elevation from a DEM. Taking into account that I want only one contour and not all contours with the given elevation, is there a way to do it in ...
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1answer
564 views

Isohyetal Map in Arcgis

How can i create Isohyetal Map in ArcGIS10. I do have the precipitation values from number of weather stations in my area of interest. What tools should i use to create these contour lines. Thanks
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1answer
334 views

How to extract information from a tiff file

I have a tiff file that I loaded into ArcGIS. It has roads, rivers and other features including the 600m contour for the region. I want to create a file that only shows the 600m contour. How can I do ...
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1answer
1k views

Label Features with Arcpy

I had run the contour tool in my script to generate polylines. Contour("rectExtract", "C:/fakepath/Class1.shp", 50,0) Now I want to label the polylines with the contour-value. If I execute this ...
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49 views

How to export Std Dev from Raster Dataset of DEM to classify current extent and execute Contour Tool with Python?

I want to create Countour Lines for a DEM which are based on a "STD dev" classificaion. My problem is that the "Std dev" is exported in an unknown type instead of a String. So the classifacation for ...
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2answers
916 views

How to create a raster (topo to raster) with non-rectangular shape?

I'm using Arcmap 10, I need to create a raster from contour lines. These contour lines were clipped out with a certain shape with the purpose to modify them only within that shape and then create the ...
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2answers
556 views

How to batch process (100s) of interpolations in QGIS or other open source software programs?

Is there an efficient way to run 100s of interpolations in QGIS or other open source software programs? I have groundwater contamination data collected from monitoring wells at about 800 different ...
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2answers
1k views

Interpolation of contours (from one “main-contour-shapefile”)

I calculated, that the best and smalest possible äquidistance (equidistant) for my map is 30m. After I generlized my DHM, I extracted contours of a intervall of 30m and smoothed them. Now I have my ...
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25 views

Pattern fill for raster contours in QGIS

How do I fill the area within raster contours with a pattern fill, instead of colors in QGIS? Is this even possible?
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31 views

Getting from PDF contour map of Z in area to values of Z specific points in area?

I have a PDF of a contour map of value Z for an area. For the same area, I have a set of points that I would like to match with Z values interpolated from this contour map. For an individual point, ...
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1answer
182 views

Filling contour levels with grain (texture) using Leaflet

I created a program to draw temperature contour map of France: This is the code: library(ggplot2) library(gstat) library(sp) library(maptools) require(rgeos) library(rgdal) library(foreign) ...
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1answer
75 views

Making DEM from contours without elevation data?

I got a shapefile with contours, but no elevation data is present. We can assume as known info, that the contours mark elevations at known steps (say, 20 m). Is it still possible to restore the ...
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1answer
198 views

How to get smooth contours from points or IDW raster in QGIS

Hello I'm an artist trying different ways of drawing contours in QGIS using points with income values. I've been able to import a shp file with the data, create a layer with centroids of the census ...
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2answers
183 views

Losing elevation values converting to CAD in ArcGIS for Desktop?

This is complex and my first question. I'm using 10.3 and need to export a lot of contour files to CAD. When I do this individually, they convert fine and retain the elevation values. Having hundreds, ...
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1answer
42 views

Duplicated vertices in contour features of GRASS?

I use GRASS to produce contours from DEM (r.contours for SRTM rasters). They looks fine, but most of the line features occures to be duplicated; i.e. verticies duplicated. Here are pictures of output ...
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144 views

Problem with contour lines thickness in bigger zoom levels

I'm a beginner user of GDAL tools. I'd like to rasterize contour lines into Tiff file (for example such region: N47E006), everything works for quite small zoom levels e.g. 10... but the problem is ...
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1answer
109 views

Problem loading the contour plugin

I have installed the contour plugin on my kubuntu 13 laptop, but when I am opening qgis (2.0.1) I get the following message: Couldn't load plugin contour due an error when calling its classFactory() ...
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2answers
1k views

How to clip a lines vector layer to a polygon layer in QGIS?

I've perused through previous questions and haven't been able to find an appropriate solution to my problem yet, so I wanted to post here. I have a lines layer (a contour map of mean annual ...
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1answer
984 views

How to create filled contour lines in QGIS?

How can I create contour lines that are filled with a graduated symbol usinq QGIS? In ArcGIS for Desktop I can do this. What about in QGIS?
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1answer
642 views

Continents geometry data / extracting contours of continents from country geometry

I have an ESRI Shapefile data from Natural Earth (Admin-0 Countries). I converted it to geoJSON format. There is no world or continents geometry there, only the county one. And I'd like to extract eg. ...
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1answer
1k views

Import SketchUp created KML contour lines model to QGIS

There's a neat trick to create contour lines based on the GE 3D terrain using Sketch-Up. The resulting KML however is a model I have looked at ways of importing KML layers to QGIS, like it was ...
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2answers
287 views

contour lines from point shape attribute

I have a point shape file and one of the attribute refers to the altitude. Is is possible to obtain a contour lines shape file in GRASS?
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2answers
1k views

Problem creating TIN from multiple contour shapefiles with ArcGIS 9.3 Spatial Analyst

I have about 20 shapefiles that contain contours lines, and I'm trying to convert them to one TIN using Spatial Analyst in ArcGIS 9.3. I included all of the SHP's as input to generate a TIN, but it ...
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1answer
1k views

Calculate the distance between two contours

I have two contour polylines (single shapefile) and I would like to calculate the mean, min and max distances between the two lines. Is there a function in ArcMap 10 (ArcInfo license, incl. Spatial ...
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1answer
67 views

Displaying contour lines calculated from SRTM in Google Earth?

I'm relatively inexperienced in GIS, but would like to display contour lines calculated from SRTM data in Google Earth. It doesn't matter whether they are actual linestrings or just an image ...
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26 views

how can I make contour lines out of points with different heigths?

I have different points in a polygon. The points have the attribute "depth" and either have 0m, 2m or 4m depth. My task is now to create some sort of contour lines with the points with the same depth ...
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32 views

GPS point elevation vs Contours layer elevation

I have some survey grade GPS points whose elevation is approx 55 feet lower than my contours layer elevations. I am using 1 ft contours and comparing point elevations with contours in the same ...