# Tag Info

## Hot answers tagged distance

4

If you're happy with the characteristics of your projection, you should just use ST_Distance(geometry, geometry). In your example you seem to be in UTM, which is a pretty good projection, so why not? It's much much less CPU intensive than the geodetic functions ST_Distance(geography, geography). (Note that ST_Distance_Spheroid() just calls into the same ...

3

In your question you explicitly state you want to find the distance and not the actual line geometry. If you have an Advanced level license for ArcMap you can use the Point Distance tool or Generate Near Table.

2

You can use GRASS plugin under QGIS instead of ArcGIS software to split the polyline by specific length. There is a tool "v.split.length - Split lines to shorter segments by length" that can do exactly what you asking, as you can see below: If QGIS with GRASS is not installed, I think it is time to try it. You need to download OSGeo4W Network Installer, ...

2

Just in case you want the distance along the parallel of latitude (and not the shortest distance) between two points at a given latitude, distance = r * (longitude 2 - longitude 1) with longitude in radians and where r, the radius of the parallel of latitude, is r = R * cosine latitude where R is Earth radius.

1

You can do this through the Vector -> Distance Matrix tool in QGIS. One of Ujaval Ghandi's excellent QGIS tutorials explains exactly how to do so here: http://www.qgistutorials.com/en/docs/nearest_neighbor_analysis.html

1

The method you would use in ArcMap would be to use linear referencing. This assumes each line seen in your image above is indeed a single polyline. You would need to convert your polyline dataset into a polylineM featureclass and set the measurement to be the length of the polyline. This creates a new featureclass that superficially looks identical but is a ...

1

Easiest way is to reference the table twice and use different conditions. One condition with the distance and one with the polygonid you want to have calculated. The result you safe as a new table. You get a new geometry with the objects within your search distance(plus the chosen feature) and the distances as a column. CREATE TABLE polygon1 AS SELECT ...

1

+proj=longlat +datum=WGS84 is a coordinate reference system (crs). If you would create a map with that, by treating longitude as 'x' and latitude as 'y', you could call it the equirectangular projection. +proj=laea stand for "Lambert Equal Area. This is planar (Cartesian) crs (unlike angularlonglat), and can be used withrgeos::gLenght`. gLength computes the ...

1

Note: many GIS distance calculators only calculate 2D distances either on the ellipsoid surface or a planar surface. Subtract the first point's elevation (z) from the second point's and take the absolute value. That's your vertical distance. Create a third point that has the elevation of point 1 but the xy (or lat-lon) coordinates of point 2. Run a ...

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