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Contour line issues

OvidiuFrantescu

Hi all,

I am working with a raster file (.tif) that I have georeferenced, and now I would like to extract the contour lines of of it.

After using the contour tool I am left with multiple lines representing a single contour line from the raster.

Basically the tool does not recognize only the center-line of the contour line from the raster to generate an unique line (see attached image).

How can I condense these lines, or generate a single (center-line) one.

Thank you,

Ovidiu

Contour line issues.jpg

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OvidiuFrantescu

So here is where I got now,

I started from scratch, captured over 250 print-screens to assemble my tiff raster, after ArcMap import I have georeferenced, projected, and reclassified the raster to display only two colors. Than using ArcScan I have extracted the center-line of each contour and placed them into a new line feature. All that is left now is to do some corrections of the resulted lines. Lots of tedious work for me, but nowhere near as much as digitizing the whole thing.

Thank you all for you input,

Ovidiu

SteveLynch

what is the min/max of the input raster and how many columns/rows does it have?

DanPatterson_Retired

those cell sizes look like decimal degrees and I suspect the data may be in GCS WGS 1984 ... which is unprojected data

OvidiuFrantescu

Hi Dan,

The data is in WGS 1984 Web Mercator.

In the contour tool I selected the interval to be 1, because the original contours are at 1 ft. intervals.

The cell size is X/Y 0.013888889, 0.013888889.

Now that you mention these, I am thinking that I should do a raster re-sampling to increase the cell size.

Any advice is greatly appreciated.

Ovidiu

DanPatterson_Retired

what coordinate system is the data in? not the dataframe but the actual data?

what contour interval did you use?

What is the cell size?

I suspect you are contouring at too fine an interval relative to your cell size and the range of values in the raster

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