[GIS] Resizing polygon features in ArcGIS Desktop based on attribute value

arcgis-desktoppolygon

I have a polygon dataset representing all the municipalities within a certain county.

Is there is a way to resize each feature in the dataset based on an attribute value?

Obviously, the features are naturally sized by their area, but I'd like to be able to resize them by – for example – population or median income for visual effect.

I know how to add and use the Scale tool on the Editor toolbar; this function is exactly what I want to do (i.e., resize / scale while retaining the shape), but I wonder if there isn't a more precise way to do this (i.e., based on the value of a certain attribute).

I know it's possible to do what I ask by selecting each feature individually then setting the scaling factor to whatever attribute value, but I'm curious if there isn't a more efficient way to do this.

Best Answer

Here are some options:

Cartogram geoprocessing tool v2

http://arcscripts.esri.com/details.asp?dbid=15638

How to make area cartogram maps in ArcGIS

http://www.gislounge.com/how-to-make-area-cartogram-maps-in-arcgis/

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[GIS] Reclass for vector data in ArcGIS Desktop

Yes. The following technique is general and works in all relational databases and (therefore) in many GISes.

Create a lookup table describing the reclassification: it will look exactly like the table in the question. Joining the lookup table to your attribute table on [Field1] completes the job.

This solution is fully automatic: any update to the attribute table or the lookup table will be immediately reflected in the join.

If you need to make the result permanent (e.g., for use in other software), use the Field Calculator simply to copy the value of [Field2] into a new field created for that purpose. This, of course, is not automatic at all and would have to be repeated whenever a value of [Field1] is changed, or [Field2] is updated in the lookup table, or records are added to the attribute table.

BTW, this used to be a great way to reclassify integer (categorical) grids in Spatial Analyst, but in recent versions, joins to grid tables do not seem to work correctly. Anyone with a positive experience in this regard please correct me (maybe the situation has improved at version 10.0?).

ArcGIS Desktop – Finding Parcel Polygon Features with Frontage on Multiple Streets

If your road network is divided by segments, dissolve the buffers based on road name or some common attribute so that individual segments of roads do not count as two separate roads in the next step.
Buffer your street centerlines by a standard amount - more than half the typical ROW width, but no so large that it would overlap parcels that do not front on it. You may want to choose different buffers for different classes of roads. When you buffer, don't merge the polygons.
Spatially join the parcels to the road buffers, choosing "one to many". The "count" field on the results should allow you to identify all parcels with two frontages.

Now you have a table with rows for every overlap between a parcel and a road. You could easily summarize this to find all parcels overlapping two or more roads using either GIS or a database. But eliminating corner lots will be more tricky. Here's one broad method:

Set up topology for the buffer layer with a rule "must not intersect".
Export all errors to a new feature class of intersections.
Spatial join the intersections to the buffer layer, choosing "one to many".

At this point you have two tables: one with all frontages and one with all intersections between roads. It won't be easy, but you can write a SQL query that selects finds all parcels that have two frontages where those frontages do not intersect. The results would be the set of all parcels that have multiple frontages that do not intersect.

One advantage of this method is that it avoids choosing parcels with edges that are not on roads, such as where a parcel is adjacent to an alley, a water features, a railroad ROW, etc. A disadvantage is that the buffering won't be perfect, and you'll still have to visually check it for errors.

I'm not sure how to write the SQL - perhaps someone else can chime in on that.

Edit Thoughts on the SQL:

It would be fairly simple to solve for parcels with two frontages as below. Then you might need to manually look at parcels with more than two frontages, but hopefully there would be few, and most would be corner lots anyway.

This might work for selecting only non-corner parcels with two frontages:

select ParcelID from parcels
where parcelID not in (
    ((select Parcels1.parcelID, intersections.intersectionID from
     intersections left join
        (Select first(RoadID) as Road1, last(RoadID) as Road2, count(*) as frontages, ParcelID
        from Parcels
        where count(*) = 2
        group by ParcelID) as Parcels1
    on intersections.RoadID = Parcels1.Road1) as int1
inner join
    (select Parcels2.parcelID, intersections.intersectionID from
    intersections left join
        (Select first(RoadID) as Road1, last(RoadID) as Road2, count(*) as frontages, ParcelID
        from Parcels
        where count(*) = 2
        group by ParcelID) as Parcels2
    on intersections.RoadID = Parcels2.Road2) as int2
on int1.intersectionID on int2.intersectionID))

Best Answer

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[GIS] Reclass for vector data in ArcGIS Desktop

ArcGIS Desktop – Finding Parcel Polygon Features with Frontage on Multiple Streets

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