Questions tagged [contour]

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

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votes
1answer
147 views

Scripts to automate conversion from DEM to contour shape files

I am using the DEM files in the Cornell CUGIR repository to build contour layers in QGIS. The problem I have is that while it is easy to do, it requires many manual steps in QGIS that are both ...
2
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1answer
57 views

Contour lines/ basement contour extraction

My purpose: getting out area between elevation contours (like b/w 600m and 700m). The contours could either be elevation ones or the basement contours. I got elevation contours using spatial analyst ...
3
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3answers
244 views

DEM polygonize (raster to vector) doesn't work for contour lines less than 1 meter apart? (QGIS)

I tried to make polygon from DEM (geotiff) in QGIS. My requirement is that elevation value was every 0.5m of polygon. If I use the function polygonize (raster to vector) , polygon is created but ...
2
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0answers
301 views

Optimize Postgis contour lines DB

I'd like to try to optimize a world-wide 10m contour lines (isohypses) Postgis database(from SRTM). The complete DB takes 504GB on disk, contour lines are already in epsg:3857, and simplified with ...
4
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3answers
4k views

QGIS Heatmap by value (NOT by point-densty)

I need a heat map generated by points value irrespective of how close or far apart the points may be in QGIS 2.6.1 So far I'm using the raster/heatmap/heatmap function. I need the same colour to run ...
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0answers
33 views

Faulty altitude point between contours

I have point(picket?) between 2 contour lines with even number altitudes. Now i got these new 5 meters steps contour in between. As you see, this point between red lines was OK, but now that this 175 ...
2
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1answer
728 views

Polygons between contour lines in QGIS?

I am trying to create polygons between contour polylines within a defined area (for which i have both polygon and polyline shps) but I seem to be thwarted at every turn. Using QGIS 2.14, I am sure it ...
2
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1answer
1k views

Download of very detailed DEM files for Portugal?

Operating system: Windows 10, 64 bit. QGIS Version: 2.13.3 which I installed via the QGIS.org website. I need contour lines for a small area in Portugal. I saw a guide posted here: http://planet....
1
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1answer
805 views

How to assign elevation values to contours derived from a raster elevation file

I extracted contours from a raster elevation file (SRTM). The contour layer does not contain elevation values. How can I use qgis to assign elevation values to the contour layer? Is there a better ...
-2
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1answer
71 views

Calculating number of roads between two polylines in ArcMap?

I have a file that contains contour lines and want to know how the number of roads that are located between each set of contour lines. How can I go about achieving this? I provided an example where ...
1
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0answers
80 views

Contouring with cliff faces in ArcGIS for Desktop? [closed]

I am trying to create some contour lines that are around cliff faces. What is the best way to create contour lines that are effected by cliff faces and is there a way to automatically draw the cliff ...
1
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1answer
485 views

Contour extraction from raster does not finish in Qgis. How to find out if a raster is damaged

Execution of "extraction" - "contours" in Qgis is impossible. The process never finishes, I stopped it after 35 min. The contour extraction works for all other raster files. I have tried with ...
1
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1answer
233 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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0answers
137 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 ...
2
votes
2answers
764 views

Generate multiple contour lines at specific elevations

Can anyone suggest a method by which I can produce several user-defined contour lines (from a DEM) within a single shapefile using QGIS/GRASS (2.12.x) and its plugins. Each approach I have tried has ...
3
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0answers
145 views

Open source alternative to the “Contours with Barriers” Tool in ArcGIS

I am trying to create a contour file for the globe for a project and am using open source GIS software packages. I was trained for several years on ArcGIS and there is a tool to create contours with ...
1
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1answer
83 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, ...
0
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1answer
197 views

Contours from NED in QGIS — “oversampled” NED? [duplicate]

I have downloaded an IMG file of NED data from the USGS National Map elevation products site and I want to create a contour map using QGIS. The problem is, the NED raster is "oversampled". There are ...
1
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1answer
64 views

Polygon Representation from Contours

I have contours lines along with their elevations in ArcGIS. I want to create a polygon representation from those contour lines. How can i create polygons from those contours which may help me to ...
2
votes
1answer
2k 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) library(...
4
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0answers
318 views

Adding intermediate contour values automatically in QGIS?

We have 100's of elevation contour shapefiles. In each file, only the 10th contour line has values (200, 450, 700, etc..). We have to attribute values for all the intermediate contour lines (2nd line ...
3
votes
1answer
414 views

How to exclude water during contour generation?

I recently acquired a LiDAR data set that included a 1 meter DEM. I generated 1, 2 and 5m contour layers but I am seeing a lot of contours within water bodies. I suspect this is either caused by wave ...
1
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1answer
190 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 ...
3
votes
1answer
686 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 overlay....
2
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0answers
192 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. ...
3
votes
1answer
1k 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 ...
-2
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2answers
67 views

Drawing Contours using ArcGIS for Desktop? [closed]

Could you explain step by step of creating contours in ArcGIS 10.1 for Desktop? Starting from data input (also I need explanation on the type of data format ) to finally drawing the contours.
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0answers
109 views

Making contour lines out of points with different heights using QGIS?

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 ...
1
vote
1answer
887 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?
3
votes
1answer
643 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 ...
4
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0answers
96 views

QGIS Contours plugin [closed]

I managed to load osm-data with osm2po, pgrouting, postgis and postgresql into qgis. Then I did a drivingdistance analysis based on cost to finally get the qgis contours plugin up and running. But ...
2
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0answers
106 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 ...
2
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1answer
273 views

Annotation masks disappearing

I have created annotation from the labels of a set of contour lines in ArcGIS and used Feature Outline Mask to create a mask layer in order to mask the lines using Advanced Drawing Options and make ...
3
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0answers
344 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 ...
1
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0answers
77 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 ...
5
votes
1answer
2k views

Contour lines with imported shapefile using Blender GIS - wrong Z values

I've been making experiments with Blender GIS and QGIS. I'm having problems when importing Shapefiles with contour lines, with a field for elevation (ELEVATION FROM FIELD selected when importing). I'...
2
votes
2answers
626 views

Adding elevation data from contour lines to point layer using QGIS?

I want to calculate the number of vacant lots within 300m from a given building. My source file contains point layers of buildings and vacant lots. Here's a short description of my workflow. I've ...
1
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0answers
143 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 ...
1
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0answers
149 views

Contours from delaunay triangles

I have generated a delaunay polygon file that represents terrain data. Is there a way I can produce contours from the polygon file? I know I can convert the polygon to an Esri TIN, and then produce ...
4
votes
1answer
2k views

Exporting Contours from QGIS into AutoCAD [duplicate]

I'm trying to export contour lines from QGIS into standard AutoCAD but I'm not having much luck. It does not seem to matter what type of file I select as the output during the contour creating (eg. ...
1
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0answers
63 views

Clip Categorized Polygon with another Polygon [closed]

I have created a contoured polygon layer from a set of csv points. My polygon layer looks like this: The issue is that over the water I don't actually have data, that area is being filled in by ...
0
votes
3answers
299 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
votes
1answer
745 views

QGIS Contour Plugin Says No Shapely; can import shapely in QGIS console

I'm keen to create some contours (isochrones for a pedestrian 'ped-shed' catchment) from a point dataset in QGIS, using the contour plugin from the Plugins repository. I installed the plugin, but ...
1
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0answers
316 views

How to create contours from an IDW raster

I'm new to QGIS and am trying to create vector contours from this IDW raster. I followed Ujaval Gandhi's "Interpolating Point Data" tutorial step by step but am not getting the same results for step ...
3
votes
1answer
2k 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 ...
2
votes
3answers
665 views

Too many contours labels are showing up in ArcMap, not just ones for selected subset?

I created a shapefile for contours lines on the basis of a raster. Since I am interested in just 5 contours (out of, say, 50), I selected for display just the contours I am interested in. I achieved ...
1
vote
2answers
852 views

Generate 3D elevation points grid from 3D contour lines!

I have a shapefile with 3D contour lines. I want that based on this information to generate for all this area a 3D grid of points with certain distance from each-other like every 50cm. I use Arcgis ...
1
vote
0answers
233 views

Import ARCGIS web dataset contours into Sketchup

My local council has online ARCGIS data sources including 1m elevation contours. I am trying to import these into a sandbox terrain model in sketchup to do some landscape planning. Conceptually I ...
1
vote
0answers
155 views

How to convert poly-line contour feature class into heat map displaying heights [closed]

I'm looking for a way to be able to convert contour data (as lines) into a heat map that would display the data warmest at the highest points and coolest at the lowest. I have access to QGIS, ArcMap ...
2
votes
1answer
2k views

ArcGIS, How do I get smoother contours?

I am trying to get nice smooth contours using ArcGIS. I have already smoothed out the DEM using focal statistics, simplified and smoothed the contours. The current result looks like this, which is way ...