Questions tagged [contour]

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

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2answers
627 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 ...
2
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2answers
2k views

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

I calculated, that the best and smallest possible äquidistance (equidistant) for my map is 30m. After I generalized my DHM, I extracted contours of a interval of 30m and smoothed them. Now I have my "...
1
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1answer
2k 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 ...
1
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1answer
2k 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 ...
19
votes
2answers
35k views

Cropping raster layer using QGIS?

How do I 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 rendering. I have ...
52
votes
3answers
17k views

Smoothing polygons in 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 ...
10
votes
4answers
2k 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
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2answers
3k 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 ...
1
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2answers
408 views

Contouring range only using ArcGIS Spatial Analyst?

I have a grid (in .img format) with pixel values ranging from -10,000 to 10,000, which i would like to contour. but i would like to contour only -3000 to 0 range. is this possible to set this up ...
2
votes
1answer
914 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 so ...
32
votes
2answers
39k views

Creating DEM from contours in QGIS?

I have a shapefile with contours and their heights. Is it possible to make a DEM from contours in QGIS without using GRASS? I found Creating DEM from contours using ArcGIS Desktop? but the answer ...
4
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2answers
4k views

Simplify Raster Contours ArcGIS 10

Does anybody know a way to simplify a number of contour polylines derived from a raster dataset? I need to generate a map that shows contour polylines at relatively small scale. With the contour ...
11
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5answers
4k views

Measuring straightness of a curve segment (represented as a polyline)

I'm working on an automatic elevation contour labeling algorithm and one of the factors that I want to take into account when deciding the positions of labels is how "straight" a particular segment of ...
16
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3answers
4k views

Generating contours from DEM using GDAL?

We have just received a large set of DEMs at work and I would like to generate contours from them. The DEMs have a resolution of 1m and a size of 1kmx1km. Output from gdalinfo: Driver: AAIGrid/Arc/...
5
votes
1answer
1k 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 ...
6
votes
1answer
3k 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 ...
11
votes
2answers
46k views

Creating DEM from contours using ArcGIS Desktop?

I have a large set of contours that I received broken down into several different subsets. I have merged most of the subsets together creating a larger set of contours in three different files. I have ...
3
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3answers
3k 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 ...
5
votes
3answers
2k 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 ...
2
votes
1answer
651 views

Checking if z values of contour lines are correct using ArcGIS Desktop?

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
2answers
7k views

Creating shaded relief in ArcGIS Desktop?

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.
4
votes
4answers
10k 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 ...
13
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2answers
2k 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 ...