[GIS] Buffer Polygon, BUT Inside and Only for a Distance

arcgis-desktopbuffer

There has to be an easy way to do this. Been plugging away for an hour and I don't know if I am brain dead or what.

What I need to do is buffer a polygon on the inside, but only for 500 metres. If you have a look at this image:

Interior Buffer

You can see exactly what I don't want to do. The selected polygons (cyan) I buffered by -100 metres. What I want to do is actually create a buffer for the area from the polygon boundary to where it buffered it here.

I know I could do an erase on the original polygon with the above buffered result, but that seems like an extra step and I want a one step solution.
I also know I could convert the polygon to a line and then buffer it, but once again extra step extra result.
Python programming could sure do this, but I really don't want to waste the time going down that road.

I do believe there is a way to do this, with one tool and one result, if not, well Esri should add that in.

I'm looking to know if there is an Esri ArcGIS Desktop tool to accomplish this?

Best Answer

You're almost there! Using the standard buffer tool, enter your desired distance as a negative value, then set the line_side parameter to OUTSIDE_ONLY. This will generate areas inside of each polygon, giving the nice look of country borders on a political map when combined with a transparency setting:

Input data

Interior buffer

Taken from my other answer

Related Solutions

ArcGIS Buffer – Creating Inside Buffer with Attributes in ArcGIS

Use the Buffer Tool from the Analysis toolbox and enter a negative value for the buffer distance. Pick OUTSIDE_ONLY for the side type and then dissolve on the relevant attributes.

Requires Advanced license.

Once attributed buffers exist can we use Definition Queries to display only certain FN’s and/or show each one with a separate symbol all from a single feature class.

buffer tool with relevant fields highlighted

Polygon – Best Way to Determine if a Point is Within a Certain Distance of a GEOJSON Polygon

This really depends on a number of factors.

Are you talking about a large number of features? Do you have 100 neighborhoods and 1000 point locations, or a thousand times that number?
Is your precision requirement high enough that you'll need to take Great Circle calculations into account? At less than 10 miles the error will be around 10-30 meters, depending on your latitude (see 2).

If either of the above are true, then you'd be much better off parsing the GeoJSON into a spatial database and making the calculations from there. MongoDB offers some geospatial capability http://docs.mongodb.org/manual/core/2dsphere/ without having to mess around with GeoJSON parsing, but you'd have to play around with some of the spatial query operators to find something that suits. The other more established Spatial databases like PostGIS and Oracle will have more tools for the job (e.g. Oracle's SDO_WITHIN_DISTANCE), but you'll have more work getting up and running.

If you don't have loads of features and you're not worried about the great circle errors, then you could try using JSTS Topology Suite to help.

Here's a basic example. You'll need to work to calculate the basic lat/lng distances involved.

var tolerance = 10;

var geojsonPolygon = {
        "type": "Polygon",
        "coordinates": [
            [
                [10.0, 10],
                [20.0, 10],
                [20.0, 20],
                [10.0, 20],
                [10.0, 10]
            ]
        ]
};

var geojsonPoint =  {
        "type": "Point",
        "coordinates":
                [0, 0]
};

var reader = new jsts.io.GeoJSONReader();

var polygon = reader.read(geojsonPolygon);

var point = reader.read(geojsonPoint);

var ptDist = new jsts.algorithm.distance.PointPairDistance();
jsts.algorithm.distance.DistanceToPoint.computeDistance(polygon,point.getCoordinate(),ptDist);

if(ptDist.getDistance() < tolerance){
    // It's within 10
} else {
    // It's further than 10
};

Hope that helps.

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