Tag Info

Hot answers tagged

4

The radius, r, of the small circle joining all points at latitude, φ is r = R cos φ where R is the radius of the sphere. That simplifies to r = cos φ if we assume a "unit sphere" (R = 1) for convenience. --------------------- A/D | r φ / | / | / | / |a / |x / |i ...


4

It doesn't matter at what longitude you are. What matters is what latitude you are. Length of 1 degree of Longitude = cosine (latitude in decimal degrees) * length of degree (miles) at equator. Convert your latitude into decimal degrees ~ 37.26383 1 degree of Longitude = ~0.79863 * 69.172 = ~ 55.2428 miles More useful information from the about.com ...


3

Both variables are zonal means. The average distance to the nearest facility is the zonal mean of the Euclidean distance grid (based on the facilities). The average number of facilities is the zonal mean of a one-kilometer radius focal sum of the facilities grid. (This is merely a grid whose cell values count the number of facilities within each cell. ...


2

Your database is not really a SpatiaLite database but a SQLite database which contains geometries which are encoded according to FDO specification. Something about FDO can be read from http://trac.osgeo.org/fdo/wiki/FDORfc16. Some other software, like TatukGIS, are also creating SQLite databases with FDO geometries. Spatialite can read FDO geometries ...


2

You'll need to use Network Analyst for this. The first thing you will need to do is turn your lines into a network. The Network Analyst Tutorial exercise 1 covers this, but be aware it may not go into sufficient depth, as there are geometry and topology considerations to take into account. Why isn't the service layer shape properly spread out? touches on ...


2

Converting your polygon to points first is a bad idea. You will not be calculating the distance to your polygon, you will be calculating the distance to the closest node of your polygons (not the edges which may be closer). You can use the NNJoin Plugin to get accurate measurements to your polygon. Make sure your layers are in the same projection before ...


2

I would approach this as follows: Convert your polygons into lines (by which each edge of the polygons - a line between the consequent vertices - will become a line feature in the output feature class.) After the conversion, the output lines will preserve their "parent" polygon ID. Use GP tool: Feature To Line. Take each point and then find out which line ...


1

Before you use this, please check out this link for a solid Vincenty example. Luckily, Javascript is very C-like so its not too hard to make it work for C++. Please also forgive any coding no-nos as this was thrown together rather quickly. My Datum is WGS84. I ran this through g++ and got a matching answer as their online calculator. I have never been ...


1

You could try using Proj4. The geod command will allow you to calculate the geodesic distance between to points. https://trac.osgeo.org/proj/wiki/man_geod I have not used the C++ API, so perhaps someone else can provide an example.


1

Thank's guys, I have solved my problem. IPolygon4 polygon = buld_F.Shape as IPolygon4; IGeometryBag exteriorRingGeometryBag = polygon.ExteriorRingBag; IGeometryCollection exteriorRingGeometryCollection = exteriorRingGeometryBag as IGeometryCollection; for (int i = 0; i < ...


1

Agree with Chris W. This field calculator expression will calculate from and to measures in a point file, providing there is a single river - polyline: def CalcFromToMeasures(shp,n): mxd = arcpy.mapping.MapDocument("CURRENT") lr=arcpy.mapping.ListLayers(mxd, "river")[0] with arcpy.da.SearchCursor(lr, "Shape@") as cursor: for row in cursor: ...


1

If I understand your question correctly, it sounds like you are trying to plot the relationship between size of wetland and distance to your sample points. I don't think there is a single tool that will do what you want in one step. The Near tool in the Proximity toolset will calculate the closest distance to the other feature. The point distance tool will ...


1

I did a quick glance at the code for the tool. It appears that default/feet choice is to specify a fixed conversion between feet and meters. This would make sense, because as I mentioned earlier in the context of metes-and-bounds you're usually using one of those units (or something archaic like chains or rods). But line 189 of the source code is just a ...


1

I suspect that your google SRID may be incorrect. I believe that google geocode results use SRID 4326 (WGS 84). I believe the google uses 3857 for the map display, but outputs the data as 4326.


1

I encountered this same issue while working on my thesis, and was able to adapt an existing tutorial to the tools available in ArcMap 10.0. I recently added screenshots and other information to clarify, so I feel it is pretty straightforward: http://kaitlinyanchar.com/arcgis-tutorial-toblers-hiking-function/ I am the author of this website.



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