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

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7
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1answer
484 views

Creating contours with meaningful values from point data

I recently obtained a CSV containing the locations of all recorded bicycle accidents in Boston over the past few years. As an avid cyclist, I'd like to create a simple contour map that draws attention ...
0
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0answers
385 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. ...
4
votes
1answer
328 views

Creating management zones in NDVI ortho maps with contour like lines

This question is hard to explain so if you have a possible answer I would love to hear it. I work in the precision agriculture business which heavily relies on NDVI calculations but need to create ...
0
votes
1answer
760 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 ...
0
votes
1answer
59 views

Editing symbology of contourlines with Arcpy

I just have a problem with my pythonscript. I had run the Contour-tool to generate polylines. Contour("rectExtract", "C:/fakepath/Class10.shp", 20,0) Now i want to mark the 100 meter lines in ...
1
vote
1answer
42 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 ...
4
votes
2answers
139 views

How to create a single contour defining the boundary between sea and land

Hello! I am still learning so forgive me if my question is very simple... I am trying to create a map with ArcGIS. The area I am working on is a seasite and I found that in some parts the cells appear ...
1
vote
2answers
499 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 ...
0
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0answers
144 views

QGIS 1.8.0-Lisboa error message when converting DEM to Contours

I am trying to convert a small DEM (1 megabyte) into contours. When I go to - Extraction - Contour- and run it I get the following message: "ERROR 1: CPLRealloc(): Out of memory allocating 416 ...
1
vote
1answer
810 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 ...
3
votes
2answers
2k views

Colouring areas between (vector) contours?

Is it possible to colour areas between (vector) contours without making it a DEM first? Joshdoe seems to have done so in Create filled contour map with GRASS but does not say how.
2
votes
1answer
284 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) ...
1
vote
0answers
480 views

Arrow flow lines from a contour map

using QGIS (or even GRASS) is it possible to label a contour lines shape with arrows that indicate the flow direction? Briefly: I have a point shape with elevation values. I make an interpolation map ...
4
votes
2answers
4k views

How to generate a DEM from a contour Shapefile?

I want to create a DEM from depth contours (shapefile) in QGIS. I've been trying to work out how to do this based on this previous question, notably from this link from that page, however I'm stuck, ...
1
vote
2answers
189 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?
3
votes
1answer
577 views

How calculate areas between certain contour lines in qgis?

Sorry for asking a question which I found in similar ways already here, but I am trying this for days and just got no result: How do I calculate the area between certain contour lines (e.g. 0-800, ...
5
votes
2answers
512 views

Finding depression with contour lines

How can I find depression contour lines? I already have find depressions via Fill-method, but now I try to detect them by using the contour lines, anyone have an idea ?
7
votes
1answer
614 views

Comparison of three contour lines

I am looking for a way to spatially quantify the difference between three contour line shapefiles. More specifically, I have two elevation rasters which I intend to create contour lines from, but ...
3
votes
2answers
3k views

How to install the Python module shapely for QGIS use?

I'm using QGIS 1.8.0 on a Mac with OSX 10.6.8 (Snow Leopard). I've installed QGIS including GDAL, GSL, UNIXImageIO, Freetype, and Matplotlib all from www.kyngchaos.com. When installing the plugin ...
2
votes
0answers
273 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--> ...
1
vote
2answers
724 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 ...
3
votes
2answers
1k views

Exporting USGS contour line shapefile to DWG or DXF?

How do I assign the Z value based on the Elevation attribute using ArcGIS 10.1 for Desktop? I've been messing with this for an hour or two now and every time the exported DWG has ZERO for z value for ...
11
votes
3answers
666 views

Contours: Interrupt contour lines beneath a elevation number

Is there a way to interrupt a contour line beneath a elevation number? Thanks!
0
votes
1answer
506 views

Most optimal algorithm for contour correctness?

Am creating an app which correctly calculates contours from a DEM file or any height-map given to it. The correctness of the contour holding the most importance, since a person viewing the contours ...
4
votes
1answer
240 views

How to use -lco options in gdal_contour?

I'm trying to create contours from geotiff raster with gdal_contour. My output format is Postgresql and I would like to ovewrite the existing table. When I do: gdal_contour -a 1 -f PostgreSQL -i 50 ...
2
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0answers
87 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 ...
5
votes
2answers
171 views

Using field calculator to delete specific contours

I have 3 contour shapefiles with 25m, 50m and 100m equidistance. Now I want to delete in the 25m-shp-file every **50m and **00m contour and in the 50m-shp-file every **00 contour. How can I show them ...
1
vote
0answers
563 views

How to clip the contour map with the polygon using R software?

Hi I am wondering how can I create the contour lines from the discrete x, y and z dataset and then add the shapefile to cut the contour lines by polygon. I want to clip the contour map by the shape ...
8
votes
1answer
494 views

How to generate a DEM from isolines and spot heights?

I have two shape files containing height information of a certain area and I need to create a raster DEM with GRASS using them. file 1 consists of height information in contours (isolines) file 2 ...
4
votes
2answers
5k views

Detailed Bathymetric/Bathymetry contour data (0-200M)

I am looking for free Bathymetric contour data in shapefile format for depths between 0-200 meters for North America. I prefer contours at 10 meter increments, but will take whatever I can get. I ...
3
votes
1answer
686 views

Problem with generating contour lines and filled contours

I am trying to create contour lines and filled contours from a shape file of height points using the contour plug in (have tried other tools but with no success). The data is sourced from the UK ...
7
votes
3answers
3k views

How to extract slope from topographic raster map?

I am working on a project for a machine learning class wherein I extract features from a topographic raster map and then classify the traversability of the terrain. One of the features I need to ...
2
votes
1answer
617 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, ...
4
votes
2answers
1k views

TIN Creation from 3D Contour File

I'm currently trying to import a 3D contour file into a Quantum GIS project. My question is, how can I export the DXF file from Microstation with height information? I already have imported it to the ...
9
votes
3answers
976 views

What are common methods for converting raster digital elevation data to vector contours?

In researching this I have found many references to the opposite, creating elevation data from contours, but nothing regarding contour creation. Preferably, I am looking for open source solutions like ...
3
votes
2answers
557 views

How to specify gdal_contour output format as postgresql table?

I want to generate contours with gdal_contour command. It generates an output as shapefile by default. I want this utility to output a postgresql (postgis) table. The documentation says there is a -f ...
0
votes
1answer
3k views

How to convert shapefile labels to graphics (in ArcMap 10)?

I have a shapefile that represents contours. Because I have clipped the contours to the map boundary they are broken in several places. Now that I have labeled the contours there are labels that are ...
3
votes
0answers
405 views

How to contour irregular point data for overlay on Google maps?

I am having some serious trouble finding a solution to fit my current needs. I am attempting to create contour maps from irregularly spaced point-data on the fly to overlay on a Google map. I have ...
2
votes
3answers
1k views

Generating raster from isolines using SAGA or ArcGIS?

I have a vector dataset of mean annual precipitation polylines, and I would like to generate a raster from them. I'm not sure the best way to go about it. ArcGIS has the Polyline to Raster tool but ...
3
votes
2answers
152 views

Selecting a suitable GIS for my project

I need to develop a web-based map using existing shape files. Using the web-map, we must be able to select a region and produce contours for that selected region. Can any one suggest the best open ...
2
votes
0answers
808 views

Dynamic Contour generation and project on google maps

Is it possible to generate contour map layer at runtime and overlap or project on google maps. I am using google map api v3 and want to generate contour map layer using data from sql server and ...
1
vote
2answers
498 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 ...
4
votes
1answer
2k views

How to create a Digital Elevation Model

How to create a DEM starting from layers shapefile "contour lines" and "shares"? which module of GRASS I need to use? thanks for yours responses....
12
votes
4answers
3k views

How to place elevation numbers on contours with uphill orientation and position?

I want to orient my elevation labels uphill. Is that possible? I'm currently using the labeling tool from QGIS (not that one in layer settings). I want the labels curved and uphill oriented (and I ...
3
votes
2answers
2k views

ArcGIS 10: How to clip point buffer to features in another layer?

I'm on a steep learnig curve here, so aplogies if my question is a one-banana problem. In ArcGIS 10 I have a contour layer that was generated from an ESR ASCII raster file (batyhmetry of the South ...
2
votes
2answers
291 views

Losing large portions of elevation contours from QGIS to PDF

Please forgive me as I'm new to GIS and all this might be a silly question, the wrong place for this question, or a hack way of going about what I'm getting at. So any suggestions on better practice ...
1
vote
2answers
893 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 ...
1
vote
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 ...
0
votes
1answer
1k views

How to generate smooth contours from cropped raster?

I’m trying to create contours from a raster layer in QGIS. On my first attempt, I cropped my raster layer in Photoshop and reimported it, but it lost coordinate data I think. I made the contours ...
6
votes
1answer
6k views

How to crop raster layer?

Can anyone tell me how to crop a raster layer in QGIS? I want to make contours from a section of a layer, and including the whole layer will create far more data than I need and slow down the ...