I have a database of map points, and I want to limit the display to showing at most ~50 points at a time. When a user zooms in, more points may be displayed. Currently, I'm just taking a random sample of the result set. This isn't great, as there can be empty areas, that when zoomed in suddenly show a point. My next thought was I co...
I would like to build a location-aware application that automatically detects a user's location and presents them a sorted list of the nearest landmarks from a landmark database. The application will be built on the iPhone. The fundamental questions are: How to calculate the distances to nearby landmarks and sort by "closest" Where to...
I've got a table of points, each with a name, latitude, longitude, and an area code. What I'd like to do is perform an aggregation (i.e. a "group by" clause) and return a polygon containing all the points for a particular area code. I'm struggling a little to even find if there are any built in aggregations for the geography data types...
I'm trying to do some network analysis for a client. The provided road-network GIS layer is of bad quality; therefore, I have to resort to Google maps to provide me shortest path between 200 points, to produce time and distance matrices between each point. is there a way i can input the layer as a set of KML points to obtain outputs of ...
Is there a way to convert a linear shape file into a csv file of the following format: Node_1, Node_2, attribute_1, ...., attribute_x 1 2 "hello" 567845.334 I have looked at GDAL/OGR2OGR and PostGIS and i don't think either converts the data to the format I want. I don't mind writing a script to do it, if i'm ...
There is any geocoding/routing service which runs on Google App Engine? (besides the Google Maps API) ...
Is there a way in arcobjects to get a unique id for a layer? If you do a search by layer name there could be possible duplicates. If there isn't a property is there a way to generate an id? I tried using the GetHash() but that didn't stay consistent. ...
I have a spatially enabled database (DB2, in this case). I need to store a large number of squares in a table. Which standard spatial SQL datatype is most suitable? I guess I could use an ST_polygon, but maybe there is a more specialized type which would give better performance better data guarantees (I want to catch it as an error if...
Some of my routes don't work because the deCarta DDS doesn't find any arc near OLL and/or DLL and the server answers: RMAN|%S=Cannot find path origin%N=0|| How to make the server search a nearby arc (SNAP) and do the route (RMAN) in a single request? ...
I'm about to develop a web mapping application with ESRI Products like ArcGIS Server and Image Server. I can't find a good comparison between the Java Web ADF and the Javascript Framework. They're of course different because one is a full environment and the other is only client side but it's much more concise and the step to start is m...
I'm pretty much a beginner when it comes to GIS, but I think I understand the basics - it doesn't seem to hard. But: All these acronyms and different libraries, GEOS, GDAL, PROJ, PCL, Shaply, OpenGEO, OGR, OGC, OWS and what not, each seemingly depending on any number of others, is slightly overwhelming me. Here's what I would like to do...
If someone have some experiences with TatukGIS developer kernel product, can you explain how to programmatically save and load layer properties like in their free TatukGIS viewer product? The environment i use were Delphi 7 and BDS 2006 thanks Edit, this code don't work: var lyrPeta: TGIS_LayerSHP; begin MapPath:= ExtractFilePat...
I have a line segment (great circle part) on earth. The line segment is defined by the coordinates of its ends. Obviously, two points define two line segments, so assume I am interested in the shorter one. I am given a third point, and I am looking for the (shortest) distance between the line and the point. All the coordinates are gi...
If I have a polyline that describes a road and I know the road width at all parts, is there an algorithm I can use to determine if a point is on the road? I'm not entirely sure how to do this since the line itself has a width of 1px. thanks, Jeff ...
Using the ArcGIS Server Flex API, is there a way to convert mouse coordinates on the screen or the a map control to spatial coordinates in the map? It seems like there's functionality to convert map points to screen points, but a function for converting in the other direction seems weirdly absent. ...
Say I have an arbitrary set of latitude and longitude pairs representing points on some simple, closed curve. In Cartesian space I could easily calculate the area enclosed by such a curve using Green's Theorem. What is the analogous approach to calculating the area on the surface of a sphere? I guess what I am after is (even some appr...
Do you know any tools available for the conversion of LAS (LIDAR data) into Voronoi diagrams or TIN (triangular irregular networks) available? Or can anyone can suggest how to do it in arcgis? ...
hi, i have .las (lidar data) file, now i wanted to know the size of it, for example how long it's width and height in kilometers... how is it possible to retrieve these kind of info? thanks a lot!!! ...
Hi, Anyone have the working code to search shapes using buffer on all layers? I see the example code in TatukGIS only work when searching on 1 layers, what i need was something like their TatukGIS Viewer that can search shape(s) in all layers when using buffers Thanks ...
hi, is there any free open source tools available for viewing TIN (triangular irregular networks) files( which i got from LAS (Lidar data) file...)? thanks! ...