geography

I am trying to calculate the closest distance between locations in the ocean and points on land but not going through a coastline. Ultimately, I want to create a distance to land-features map. This map was created using rdist.earth and is a straight line distance. Therefore it is not always correct because it not taking into account the curvatures of the coastline. c<-matrix(coast_lonlat[,1], 332, 316, byrow=T) image(1:316, 1:332, t(c)) min_dist2_feature<-NULL for(q in 1:nrow(coast_lonlat)){ diff_lonlat <- rdist.earth(matrix(coast_lonlat[q,2:3],1,2),as.matrix(feature[,1:2]), miles = F) min

I have a SQL Server 2008 table with a column of the geography datatype. The value is a point (latitude and longitude). How do I query the table to return all rows where the location is within a 10 kilometer radius of a given coordinate? You probably want the STDistance method: http://msdn.microsoft.com/en-us/library/bb933952.aspx Or the STWithin method: http://msdn.microsoft.com/en-us/library/bb933991.aspx This query eventually solved my problem: DECLARE @geoMyPoint geography SET @geoMyPoint = geography::STGeomFromText('POINT(56.5667 9.0333)', 4326); SELECT vchZipCode, nvcCity, vchLat, vchLong

I got a raw Longitude/Latitude data whose format cannot be processed by R map. So I wonder if there are some R functions or algorithms to help me to convert those raw data into a readable format. (Maybe UTM) Here is the raw data I had: Latitude: "32-14-23 N" "31-04-27 N" "33-45-28 N" Longitude: "121-22-38 W" "119-30-05 W" "122-47-52 W" I wish to convert the format as(the sample below is mock data): Longitude: -2.748 Latitude: 53.39 Looks like you have data in degree / minute / second format and you want it in decimal format. You can use the char2dms function in the sp package to go from

I've written a small application that reads in from a series of KML files and then converts them into the Microsoft.SqlServer.Types.SqlGeography type using the following code: private SqlGeography CreateGeographyFromKML( string kml, bool debug ) { // use SqlGeographyBuilder to help create the SqlGeography type var geographyBuilder = new SqlGeographyBuilder(); // Get co-ordinates var xml = XDocument.Parse(kml); var df = xml.Root.Name.Namespace; XElement coordinates = xml.Descendants(df + "coordinates").Single(); // set the Spatial Reference Identifiers that will used to create the point

I have table with data from GPS, e.g.: Latitude , Longitude , Time , UserId How to aggregate total distance in specified time frame summing all distances by all points (ordered by time) and group data by user? Thanks If you are using SQL Server, you might be interested in using the geography data type so you can request the database using the dedicated method and geographical index. The geography data type is available since SQL Server 2008, you can more information right here: http://msdn.microsoft.com/en-us/library/cc280766.aspx Once you've got the data into the geography column, you will be

I have a table in SQL Server that has geography datatype column in it. I want to query this table to find rows that fall near (within a range) of another given geography point. Does anyone have any ideas as to the best way to do this? I have 2 options of where to do this type of query. I can write it on the sql server as a stored proc or I can do it in c# code as I am using the Entity Framework for data access. I would have a query that has a range (eg 100m) and a geography point passed in to it. The pseudo code would be something like this... select rows where rows.geo within range of given