Tag Info

Hot answers tagged

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 ...


9

I made a custom Create Buffer Interval toolbox for you: In ArcMap open ArcToolbox, right click in the whitespace and click Add Toolbox. Browse to the one I made and run the Create Buffer at Interval tool. Here's a screenshot of the parameters: It should be pretty straightforward, but let me know if you have any questions!


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

Here's some R code that does the job, the caveat being we are in cartesian coordinates. The input matrix coords is a 5x2 matrix of x,y columns, with the last point being coincident with the first point. This is what you get out of spatial objects in R when you read a shapefile, for example. thinrect <- function(coords, factor=1/3){ dx = ...


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

I suggest to use one of the LAEA or LCC Europe projections: EPSG 5633, 5635, 5636, 5638 LAEA Europe EPSG 5632, 5634, 5637, 5639 LCC Europe All EPSG codes of the same type seem to have the same projection parameters. ESRI also offers projections Europe_Albers_Equal_Area_Conic (102013) and Europe_Equidistant_Conic (102031), but they almost look the ...


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 can do this with a SQL Statement in MapInfo either thru the SQL Select dialog or thru the MapBasic window. If the polygons in your development table overlap, you might need to combine these to find the correct percentage, that is avoiding a common area to get calculated more than once in your percentage. If you need to combine the development objects ...


3

This can be solved with a model but there are 4 caveats: You need an Advance (ArcInfo) license This model assumes your rectangle is a rectangle so the 2 vertical sides are longer Your rectangle is constructed from 4 vertices only If you want to automate this then all your rectangles must have the same dimensions So after running this model you you are ...


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

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

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

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

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 - ...


2

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 ...


2

The field calculator cannot be used in that way. If you want to create buffers, use the buffer tool from the vector menu. The buffer function and other geometry functions in the field calculator can be used for calculations but not to create new geometries/features. For example to check if the features intersect a certain geometry: intersects( buffer ...


2

if you have ArcInfo, you could use "polygon to line" to have topological arcs. Based on the attribute table, you can select the lines which do not have values of -1 in the left or right. Then you select the polygons that intersect those lines and you invert the selection. Another solution is to use the dissolve tool (no multipart polygons). Then a spatial ...



Only top voted, non community-wiki answers of a minimum length are eligible