geospatial

问题 This example should be reproducible, the first part (with large polygons) works, the second fails: library(raster) USA.altitude <- getData('alt', country='USA') lower48 <- USA.alt[[1]] Srs1 = Polygons(list(Polygon(cbind(c(-96,-95,-95,-96),c(40,40,41,40)))), "s1") Srs2 = Polygons(list(Polygon(cbind(c(-97,-96,-96,-97),c(40,40,41,40)))), "s2") spdf.large <- SpatialPolygonsDataFrame( SpatialPolygons(list(Srs1,Srs2)), data.frame( z=1:2, row.names=c("s1","s2") ) ) plot(spdf.large) usa.average.elev<

问题 I have a documents contains list of location "boxes" (square area). Each box is represented by 2 points (bottom-left or south-west, top-right or north-east). Document, for example: { locations: [ [[bottom,left],[top,right]], [[bottom,left],[top,right]], [[bottom,left],[top,right]] ] } I'm using 2d index for those boundaries points. My input is a specific location point [x,y] and I want to fetch all documents that have at list one box that this point is located in it. Is there any geospatial

问题 I have a documents contains list of location "boxes" (square area). Each box is represented by 2 points (bottom-left or south-west, top-right or north-east). Document, for example: { locations: [ [[bottom,left],[top,right]], [[bottom,left],[top,right]], [[bottom,left],[top,right]] ] } I'm using 2d index for those boundaries points. My input is a specific location point [x,y] and I want to fetch all documents that have at list one box that this point is located in it. Is there any geospatial

问题 I have a bounding box of a city containing points. I would like to divide this bounding box into sub boxes according to the importance of the points. For example, regions with more points should correspond to higher number of sub-boxes. Regions with less points should respond to less boxes with larger width. I understood that a good data structure for that is a quad tree or maybe a KD-Tree. It turns out that most of these libraries just return me the nearest neighbor (This is their main use).

问题 I've done a bit of reading on this but there's hardly any information on doing it using points and the st_distance function in mysql. I suppose this makes sense since according to http://bugs.mysql.com/bug.php?id=70494 it wasn't even documented until halfway through last year. Almost every solution I've seen instead uses separate long and lat columns, and then puts them into the haversine formula like this: sorting distance in MySQL PHP This seems like a really messy way of doing it though

问题 I've done a bit of reading on this but there's hardly any information on doing it using points and the st_distance function in mysql. I suppose this makes sense since according to http://bugs.mysql.com/bug.php?id=70494 it wasn't even documented until halfway through last year. Almost every solution I've seen instead uses separate long and lat columns, and then puts them into the haversine formula like this: sorting distance in MySQL PHP This seems like a really messy way of doing it though

问题 I am trying to import an openstreetmaps shape file in R using the rgdal package. The shape file I downloaded has 5 components in it: places.cpg places.dbf places.prj places.shp places.shx The files can be accessed at the following location: https://drive.google.com/open?id=0B1ITb_7lHh1EUFVfVWc4ekRfSnc I have to do the following: 1) Import the shape file 2) Extract lat/long of the point or centroid of shape in case of polygon 3) Attach the lat/long pair to the dbf file to do some analysis I am

问题 Could you please help me to find the right solution how to access to the individual points of multi-polygon object in mysql? Here is the object: "geometry": { "type": "MultiPolygon", "coordinates": [ [ [ [-105.00432014465332, 39.74732195489861], [-105.00715255737305, 39.74620006835170], [-105.00921249389647, 39.74468219277038], [-105.01067161560059, 39.74362625960105], [-105.01195907592773, 39.74290029616054], [-105.00989913940431, 39.74078835902781], [-105.00758171081543, 39.74059036160317],

问题 Could you please help me to find the right solution how to access to the individual points of multi-polygon object in mysql? Here is the object: "geometry": { "type": "MultiPolygon", "coordinates": [ [ [ [-105.00432014465332, 39.74732195489861], [-105.00715255737305, 39.74620006835170], [-105.00921249389647, 39.74468219277038], [-105.01067161560059, 39.74362625960105], [-105.01195907592773, 39.74290029616054], [-105.00989913940431, 39.74078835902781], [-105.00758171081543, 39.74059036160317],

问题 I just converted my SQL Server 2008 database from using a lat/long pair to using the new geography type. I run queries on businesses that are within 30 miles of a geography::Point, using the STDistance function, like so: WHERE this_.GeoLocation.STDistance(geography::Point(42.738963, -84.5522, 4326)) <= 48280.32 Here is the index that I have on the geography column: CREATE SPATIAL INDEX IDX_Business_GeoLocation ON Business (GeoLocation) USING GEOGRAPHY_GRID WITH ( GRIDS = ( LEVEL_1 = LOW,