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12

If you are interested in an implementation look at jsts a Javascript implementation of the much used Java Topology Suite library -- depending on whether you prefer reading Javascript or Java, I suppose. A general idea of how the algorithm works. For points, it is trivial, you simply buffer them by a given radius. If you have multiple points, you will have ...


7

In step 4, you have to change the CRS from NAD83 to another projection that uses metres as units. It depends on the extent of your data which one is best. Unfortunately, your data is located all over the world, so you could: Create a custom CRS using aeqd (or tmerc) for each one, and draw just that one buffer with it. Practically, you only have to create ...


6

Using the buffer tool, you should be able to set the buffer to the values in a field. Selecting the 'field' radio button rather than the 'length' option in the Distance section, you can define the buffer width using table values.


6

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: Taken from my other answer


6

Starting in ArcGIS 10.0, running the Buffer tool on a point or line feature class with a geographic coordinate system (e.g. WGS84, NAD83) results in geodesic buffers that are completely free of distortion. That is probably what happened here, except that your data frame's coordinate system is distorting the area. From the help page (emphasis mine): You ...


5

Would something like this work for you? I'm assuming that the right of way area includes both sides of the road and that you know the length of the road you are measuring. // Use the same sq distance measurement as your buffer, a sq meter area uses a buffer in meters var_area = 500 road_length = 100 buffer_distance = (var_area/road_length)/2 ...


4

How about this for an idea. Run your data through the near tool to create a table of distances. Sort this table by distance then identify the distance that is your 50% of points. This would be the buffer distance.


4

If you use the v.buffer tool in the Grass Commands toolsets, you can make a flat buffer. There there are two choice boxes If you have Make outside corners straight set to No, and Don't make caps at the ends of polylines as Yes, the result should be similar to the ArcMap straight edge buffer. The following are the 3 combinations of the above two ...


4

I think you want to exclude the intersection of the buffer in the where clause. WITH subq AS ( SELECT p.id, p.name, unnest(ARRAY(SELECT q.name FROM w_point q WHERE p.id != q.id AND NOT ST_Intersects(q.geom, ST_Buffer(p.geom, 0.1)) ORDER BY ST_Buffer(p.geom, 0.1) <#> q.geom LIMIT 5) ) as name FROM w_point p ) SELECT ...


4

Yes, you can have your buffer in meters just by adding Meters in your field 'BUFFER' like 1000 Meters, 250 Meters.. and so on. This is documented on ArcGIS resources - Buffer (Analysis) Here is the snippet from site stating this capability. If a field from the Input Features is used to obtain buffer distances, the field's values can be either a ...


4

Running the buffer tool will create a second polygon offset the distance you specify from the first. Corners are radiused by default, no need to crop.


3

Since the script linked at the end of Aaron's code can only be used for square buffers and doesn't make use of the newer arcpy.da module, I've written a script that can be used to create rectangle buffers. On a 10k random point dataset, it completed in 10 seconds: import os, arcpy point_FC = arcpy.GetParameterAsText(0) w = ...


3

Try using a combination of the Multiple Ring Buffer tool and then the Polygon to Line tool, this should give you what you are looking for.


3

your coordinates are probably in lat/long with degrees as a unit. therefore, along meridians or near the equator, one degree is approximately 111km (circumference/360). note that this will change depending on the distance to the equator. A good practice is to use a local projected coordinate system that is appropriate for your location in order to have a ...


3

As a shapefile FIDs' are contiguous and 0 based, you can use that to your advantage: import sys, os, arcpy InFC = sys.argv[1] # must be a shape file OutFC = sys.argv[2] # change as appropriate DivisorSize = 1000 BufferDistance = 100 TempDir = os.environ.get("Temp") MaxFeat = int(arcpy.GetCount_management(InFC).getOutput(0)) StepRange = ...


3

This question is a year old but this alternate solution may be helpful to others. If you are using the Popup class you can set the Popup to a global variable so that you can set it not to show the window while updating. To prevent getting the "No information available" window, just set visibleWhenEmpty to false and hideDelay to 0: var popup = new ...


3

There are two strategies to handle this. One is to replace the tracks by closely spaced sequences of points and then apply the alpha hull techniques suggested in some comments. Perhaps a simple and faster way uses a raster representation (such as the image in the question itself). I will discuss the latter. A little simplification--perhaps by dilating ...


3

You have to use a projected CRS like UTM (for your part of the world) to get real circles and meters as units. Please do not use Google/Web Mercator, it does not use real meters as units (only at the aequator).


3

Completely edited my previous answer. First of all, you're dealing with @52k points so whenever you're running an analysis with this amount of data, chances are QGIS looks frozen but more often than not it is still processing (can check this with Task Manager and CPU usage). To start, we need to filter out all the unnecessary points we don't want so I ...


3

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, ...


3

Super simple. Change side type to 'Outside Only' and you got it:


3

As you have already mentioned in your comment Rudolf, you may have performed a Query which only filters out features, it does not perform any analytics. The Intersect will 'cut' out features which intersect one another and outputs the results in a new layer. The Intersect function can be found in: Vector > Geoprocessing Tools > Intersect


3

Ensure that your polygons have an area attribute separate from the one that is/may be automatically updated by the software when the shape is edited. Intersect your buffer and polygon layer. In the resulting layer, open the attribute table. If there is a new/correct area field in the same units as the original area field from step 1 you can use that - ...


3

Have you tried to write the different distances in a python list : [356.8,792] as describe in the ressources : http://resources.arcgis.com/en/help/main/10.1/index.html#//00080000001p000000


3

ST_Collect is probably not the function you are looking for, as this simply combines geometries into a geometry collection of some type, and does not actually union/dissolve them. ST_Union, on the other hand, does dissolve overlaps, and assuming polygonal input (which is most probable in conjunction with ST_Buffer and an input table called point), and ...


3

To do this I would use two tools: Intersect (Analysis): Computes a geometric intersection of the input features. Features or portions of features which overlap in all layers and/or feature classes will be written to the output feature class. then Summary Statistics (Analysis) Calculates summary statistics for field(s) in a table.


2

I know two and a half ways to create single sided buffers directly with open source tools. OpenJUMP buffer tool can do left side/right side buffers (advanced options). Spatialite 4.1 has SQL function SingleSidedBuffer http://www.gaia-gis.it/gaia-sins/spatialite-sql-latest.html PostGIS perhaps does not have single sided buffer yet but is has OffsetCurve ...


2

Here's the approach I would suggest: Use the Union tool with your buffer feature class as the only input. This will effectively split each polygon at the boundaries of any others. Run the Find Identical tool on the output from the Union tool, using only SHAPE as the categorization field. Join the output table from Find Identical back to the Union output's ...


2

I was just looking for the same answer myself and while my answer is not 'official', it's based on my interpretation of this Training Manual entry I found: http://docs.qgis.org/2.2/en/docs/training_manual/answers/answers.html#basic-distance-from-high-schools I think the above illustrates the buffer segments quite well. My answer is therefore... The ...


2

I believe that you are probably encountering the same problem that has been discussed in the old Esri Discussion Forums under the aptly named title of "True Curves, True Evil". I have a reproducible (but long) test case of this phenomena in a Python/ArcPy script that I used to convince a client that what we were seeing was explainable and could be worked ...



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