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

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2
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2answers
59 views

Slope Analysis in QGIS

Im New to QGIS, I have the Contour Information in the form of Line Features, How can I do a Slope Analysis. Is it Possbile at all? For Reference I am attaching the Image. the lines in the Polygon ...
1
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0answers
9 views

Any way to remove 2 point polylines in bulk?

QGIS: I have successfully created contours from a DEM and subsequently cleaned them up using generalizer tools in the following order: 1. Vertex reduction 2. McMinimans distance algorithm. The ...
4
votes
0answers
66 views

Convert raster to smooth contour polygons in QGIS

I have had limited success creating smooth contour polygons from a raster layers. I have created contour lines and boundary polylines and then used QGIS Union. Then I use QGIS Polygonize. Then ...
1
vote
1answer
34 views

Grid thematic map in Mapinfo

I have a tab file with the contour lines for an area, and also a tab file with the land polygon. Now, I'm following a tutorial written by a colleague a couple years ago, where a thematic map is ...
0
votes
0answers
36 views

Drawing contour with python QGIS?

I have one point layer and one contour layer and I was trying to draw a line around one contour, making a circle but not a uniform one, it has to have an irregular shape. I cannot find a tool that ...
-4
votes
1answer
45 views

Help with definition query [closed]

I have a layer of 5ft contour lines, and it includes a field called "Elevation" that has the elevation of that particular line in feet, (ex: 1555, 1560, 1565 etc.). I want to only show lines for every ...
-1
votes
0answers
28 views

Using ArcGIS Spatial Analyst for elevation?

I have many csv files of ~1000 points with elevation and x,y data. These points were manually recorded off of scanned images of the surveyor's drawings at an archaeological site. I have made each of ...
0
votes
0answers
18 views

Contouring and rendering bathymetric & other attributes in QGIS

I wish to visualise (2d & 3D) and contour point sampled bathymetric and other associated attribute data (biovolume and bottom hardness) in QGIS. The source data files are CSV files consist of ...
1
vote
0answers
9 views

Converting Labels to Annotations moves position of labels

Why are my contour line labels moving after I convert them to annotations? I am using Maplex to place them. But if they still move after I converte them to annotations, the whole maplex placing ...
3
votes
1answer
63 views

How to fix label contour lines layer displays on top of all layers in QGIS

How can I fix the situation, when the label contour lines displays (on top of all layers) on top of this layer? QGIS 2.15.0-Master
0
votes
0answers
13 views

Converting polygons to contours based on value in polygon table

I have the following and data and have been asked for a map that shows the same data set but displayed as contours. Each polygon has a value in it's table called "count". The "count" field is used to ...
2
votes
1answer
33 views

How to calculate mean elevation in a DEM between a specific interval?

I have a DEM with different elevations between 100 m & 3828 m. I just want to calculate mean elevation higher than 1500 m? Can I do that?
3
votes
1answer
49 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
votes
1answer
29 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 ...
2
votes
3answers
75 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 ...
1
vote
0answers
35 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 ...
1
vote
3answers
50 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 ...
1
vote
0answers
24 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
votes
1answer
59 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
votes
1answer
63 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: ...
0
votes
1answer
33 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 ...
-3
votes
1answer
58 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 ...
1
vote
0answers
18 views

Contouring with cliff faces in ArcGIS for Desktop?

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 ...
0
votes
1answer
39 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
vote
1answer
31 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?
2
votes
0answers
39 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
77 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
votes
0answers
35 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
vote
1answer
33 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
votes
1answer
34 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 ...
0
votes
1answer
39 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
372 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) ...
3
votes
0answers
76 views

Is it possible to add intermediate contour values automatically in QGIS?

Let me explain the scenario. We have 100's of elevation contour shp files. In each file, only the 10th contour line has values (200, 450, 700, etc..). We have to attribute values for all the ...
3
votes
1answer
101 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
vote
1answer
89 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 ...
1
vote
1answer
122 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 ...
2
votes
0answers
46 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. ...
1
vote
1answer
99 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
votes
2answers
41 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.
1
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0answers
30 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 ...
1
vote
1answer
70 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?
2
votes
0answers
64 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 ...
0
votes
0answers
51 views

Calculate z value for contour line from x,y in dxf file

I am working on a project about route chart and cross section generation for hiking with Hong Kong Lands Department's Digital Topographic Map B5000 (sample). Height information are required for this ...
4
votes
0answers
58 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
votes
0answers
53 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 ...
0
votes
0answers
49 views

Terrain elevation in QGIS

How can I get started with creating a map with elevation just like this one: Basically I need a map that looks like the one above. Can someone tell me where can I get the data, and how do I process ...
2
votes
1answer
80 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 ...
0
votes
0answers
77 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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0answers
46 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
312 views

Contour lines with imported shape file 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). ...