Scroll to navigation

shptreetst(1) shptreetst(1)

NAME

shptreetst - execute a spatial query on an existing spatial index

SYNOPSIS


shptreetst
shapefile [minx miny maxx maxy]

DESCRIPTION

shptreetst executes a spatial query on an existing spatial index (.qix), that was created by the shptree(1) utility. This utility is useful to understand how a search of a Shape data set and its qix index works.

OPTIONS

The name of the .shp file index.
Extents to render

EXAMPLE

shptreetst esp 879827.480246 4317203.699447 884286.289767 4321662.508967

This new LSB index supports a shapefile with 48 shapes, 4 depth
shapes 6, node 4, -13702.315770,3973784.599548,1127752.921471,4859616.714055
shapes 5, node 3, -13702.315770,3973784.599548,614098.064712,4460992.262527
shapes 1, node 1, -13702.315770,3973784.599548,331587.893495,4241748.814186
shapes 1, node 0, 141678.278400,3973784.599548,331587.893495,4121164.917599
shapes 1, node 0, 268807.855447,4193028.047889,614098.064712,4460992.262527
shapes 1, node 0, 268807.855447,3973784.599548,614098.064712,4241748.814186
shapes 7, node 4, -13702.315770,4372409.051076,614098.064712,4859616.714055
shapes 1, node 0, -13702.315770,4372409.051076,331587.893495,4640373.265714
shapes 3, node 1, -13702.315770,4591652.499417,331587.893495,4859616.714055
shapes 1, node 0, -13702.315770,4712236.396004,176207.299326,4859616.714055
shapes 2, node 0, 268807.855447,4372409.051076,614098.064712,4640373.265714
shapes 3, node 2, 268807.855447,4591652.499417,614098.064712,4859616.714055
shapes 2, node 0, 424188.449617,4712236.396004,614098.064712,4859616.714055
shapes 1, node 0, 424188.449617,4591652.499417,614098.064712,4739032.817468
shapes 2, node 1, 499952.540988,3973784.599548,1127752.921471,4460992.262527
shapes 2, node 0, 499952.540988,4193028.047889,845242.750254,4460992.262527
shapes 5, node 3, 499952.540988,4372409.051076,1127752.921471,4859616.714055
shapes 1, node 1, 499952.540988,4372409.051076,845242.750254,4640373.265714
shapes 1, node 0, 655333.135158,4372409.051076,845242.750254,4519789.369127
shapes 1, node 0, 499952.540988,4591652.499417,845242.750254,4859616.714055
read entire file now at quad box rec 20 file pos 1084
result of rectangle search was
8, 10, 36, 37, 38, 39, 42, 46,

Result:

The above output from the shptreetst command tells us that the existing .qix index is for a Shape data set that contains 48 shapes; indeed the Shape data set used in this example, esp.shp, contains 48 polygons of Spain. The command also tells us that qix file has a quadtree depth of 4.

Most importantly, the resulting shape IDs (or feature IDs) that were contained in the bounding box that we passed in our example were returned at the bottom of the output: "8, 10, 36, 37, 38, 39, 42, 46". You can use a tool such as QGIS to view those feature IDs and check what shapes MapServer is querying when a user clicks within that bounding box.

SEE ALSO

shptree(1), shptreevis(1), sortshp(1)

18 September 2022