A geometric element defined by a pair of x,y coordinates.
7
votes
2answers
825 views
For a given feature find the closest point along a given path
Looking for a Java based (foss4g) solution for the following:
I am using a path along with a buffer to find features that are along the path. For each of the features returned I want to find the ...
7
votes
4answers
8k views
How to find the distance of a point along a polyline?
We need to find the distance of a series of point along a given polyline.
We have a polyline dataset repsenting rivers in a catchment, broken up into river reaches (FID 1 through 35 for example).
We ...
6
votes
1answer
509 views
Interpolation: irregular shape, merging DEM's
my problem is quite complex, though I hope that solution may be simple or at least possible.
I do have .img DEM 0.5x0.5m. DEM consists of river bed, river valley and adjacent areas (it is strip of ...
3
votes
3answers
629 views
Spatial Database Design (PostGIS) - Point data that doesn't always have spatial data
I am creating a spatial database using PostGIS.
I am storing the attributes and location of some species records that can be represented as points. The records are recorded from either:
a) static ...
13
votes
4answers
787 views
algorithm to place maximum number of points within constrained area at a minimum spacing
I have a polygon layer that describes a constraint; I wish to add points within this area. I want to add as many points as possible, but they must have a minimum spacing between them. Is it possible ...
19
votes
6answers
2k views
How to compare two spatial point patterns?
If I have two point pattern distributions within the same geographic region, how would I go about visually and quantitatively comparing those two distributions?
Also assume I have many points within ...
2
votes
2answers
918 views
how trace polyline between two points?(Esri)
How i can draw a line between two points...e.g.: I have initial point and endpoint
and i need trace a line between this points...how i can do that?
2
votes
2answers
427 views
wkb/wkt according to OGC
how can i store my coordinates in wkb.. i want to know its implementation of wkb and wkt in db .. any one can please guide me.
5
votes
9answers
6k views
ArcGIS: Create a line layer from a point layer and csv data file
UPDATED DECEMBER 20
I have a Regular point layer and a csv file that has the same ids as the point layer. The csv file is organized as
ID From To Weight
-- ---- -- ------
01 ...
6
votes
7answers
2k views
Extract raster values at points
How can I extract values from a raster by points. I prefer not in Arcgis. I prefer in Qgis or Mapwindow or other open source gis.
11
votes
7answers
303 views
Public reprojection services
Are there any free public services where I can send one point in a coordsystem and it returns the point reprojected in a specified coordinate system?
I will not be doing many requests, for now it is ...
3
votes
3answers
888 views
Is there a way to “disperse markers” across multiple point layers?
I have a bunch of point layers which often have overlapping features. The disperse markers geoprocessing tool works within a layer but is there a way to do it across more than one layer, so none of ...
2
votes
3answers
300 views
UK National Grid references and GeoDjango
Newbie question. I'm trying to insert some UK National Grid references into a Django PointField defined as follows:
oscode = models.PointField(srid=27700, null=True, blank=True)
My question is ...
14
votes
2answers
2k views
How can I find a point inside a polygon in PostGIS?
How can I find a point that is guaranteed to be within a given polygon in PostGIS?
I am aware of the ST_Centroid function. However, the centroid is not always within a polygon, see below:
...
11
votes
8answers
4k views
How can I convert an excel file with x, y columns to a shapefile?
How can I convert an excel file with x, y columns to a point shapefile?
There are some somewhat optional requirements in addition to the correct creation of a shapefile:
Column types (as per ...
10
votes
4answers
616 views
Point Pattern Analysis Algorithms
I'm looking for point pattern analysis algorithms and literature on point pattern analysis, online resources and book titles welcome. The topics may range from general descriptions of algorithms to ...
