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

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3
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1answer
523 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 ...
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3answers
2k 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 ...
9
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3answers
764 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 ...
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vote
1answer
597 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 ...
2
votes
2answers
361 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 ...
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1answer
2k 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
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0answers
338 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
747 views

Generate raster from isolines

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
149 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
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0answers
645 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 ...
2
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1answer
1k 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....
3
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2answers
1k 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
249 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 ...
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vote
2answers
681 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 ...
33
votes
1answer
4k views

How to smooth the polygons in a contour map

Here is a contour map for which all the polygons of levels are available. Let ask how to smooth the polygons keeping all vertices preserved in their exact locations? Indeed the contour is made on ...
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 ...
4
votes
4answers
757 views

How to automatically plot intermediate contours with QGIS, GRASS GIS or SAGA GIS?

I'm mapping a steep mountain range. My main contour interval is 50 m and my intermediate contour interval is 10 m. In steep areas, the interval of 10 m is too small, so I need to leave ...
7
votes
2answers
783 views

What is the smallest contour interval possible when derived from a DTM?

I am converting a 2m DTM to contours, and would like to have the smallest interval possible. Is there a theoretical limit, or even a rule of thumb for defining contour intervals based on the ...
7
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2answers
2k views

How to Create Contours for Zonation

I'm still new in the world of GIS. I'm currently doing some zonation with "test points." Each has its own coordinates and "P" value. I want to make contours of these data, to divide the whole area ...
4
votes
1answer
568 views

Obtaining a contour as a single polygon in ArcGIS?

I have a DEM that I want to retrieve a single contour polygon from at a given elevation. I can use the Contour tool to obtain a series of polylines at a given elevation by setting the contour interval ...
5
votes
1answer
1k views

Create filled contour map with GRASS

Background I'm trying to make contour/isoline/isochrone maps to show what areas are within walking distance to schools for my pet project to help with the Safe Routes to School program. I followed ...
4
votes
3answers
1k views

How to position contour labels in Maplex above the line?

I would like to utilize the "contour placement" options of "Uphill alignment" and "Laddering" while positioning the label above the contour not over it. This does not seem to be an option under the ...
3
votes
2answers
3k views

How to create shaded relief in ArcGIS?

How can I create shaded relief from contour lines (.shp format)? I see Hillshade in ArcToolbox, but it asks for a raster file. I have ArcGIS 10.0.
3
votes
2answers
1k views

Java Contour Algorithm

Does anyone know if there is an open source project in Java that will take a set of (x, y, z) points and create a contour map for Google Maps/Earth? There does not seem to be a good contouring ...
2
votes
2answers
382 views

Easiest way to check if z values of contour lines are correct

What is the easiest way to check if z values of contour lines are correct in ArcGIS? I need just to look at the values, to see if equidistance between them is correct and unchanged.
4
votes
4answers
4k views

Symbology of contour lines in ArcMap

I have contour lines with height values from 0 to 1030 (sorted by height 110, 115, 120, 125). Values with in-between number (like 5, 15, 115, 135...) should be grouped and colored with same color, and ...