GIS and SQL Server 2008: Making Maps with your Data. When Microsoft introduced Geographic Information Systems (GIS) into SQL Server with SQL Server 2008, it opened up a whole range of new applications that were previously impossible to do with SQL Server. So what sort of things can you do with GIS Data? We asked an expert! In their everyday lives, people are surrounded by technology that uses Geographic Information Systems (GIS), from viewing images on Google Earth, to navigating their cars with the aid of a Global Positioning System (GPS, a real-time GIS). In each of these examples a spatial query is implicitly performed when the user picks a location. SQL Server 2008 brings with it two new spatial data types, allowing spatial data to be stored, queried and rendered from our relational database tables, and opening the door to the development of GIS-enabled SQL Server applications. GIS is usually used for creating maps, for presentation as internal reports or for publishing on the internet.
Figure 1: A GIS map showing store locations. Information Retrieval: CHAPTER 16: CLUSTERING ALGORITHMS. Edie Rasmussen University of Pittsburgh Abstract Cluster analysis is a technique for multivariate analysis that assigns items to automatically created groups based on a calculation of the degree of association between items and groups.
In the information retrieval (IR) field, cluster analysis has been used to create groups of documents with the goal of improving the efficiency and effectiveness of retrieval, or to determine the structure of the literature of a field. The terms in a document collection can also be clustered to show their relationships. The two main types of cluster analysis methods are the nonhierarchical, which divide a data set of N items into M clusters, and the hierarchical, which produce a nested data set in which pairs of items or clusters are successively linked. 16.1.1 Introduction Cluster analysis is a statistical technique used to generate a category structure which fits a set of observations. 16.1.2 Applications in Information Retrieval 16.2.1 Introduction.
Reverse Nearest Neighbor Queries. The most popular variant of nearest neighbor query is reverse nearest neighbor queries that focuses on the inverse relation among points. A reverse nearest neighbor (RNN) query is to find all the objects for which is their nearest neighbor. A reverse nearest neighbor query is formally defined below. Definition: Given a set of objects and a query object , a reverse nearest neighbor query is to find a set of objects so that for any object and set of a query may be empty or may have one or more elements.
Korn and Muthukrishnan [KM00] answer RNN query by pre-calculating a circle of each object such that the nearest neighbor of lies on the perimeter of the circle as shown in Fig. . . Contain so both are the reverse nearest neighbors of . Stanoi et al. , the number of reverse nearest neighbors cannot exceed six. In six regions of equal size to as shown in Fig. . Of in region ; either is the RNN of or there is no RNN in . Is the nearest neighbor of but it is not the RNN because lies closer to it than . In . . . Where. DistanceCalculator Class. Earth in the units described in the units desired. This last argument is really the only reason that there are multiple accessor methods, and as one may guess the implementation of the accessor methods is therefore quite simple. When the distance function is called, it proceeds to acquire and parse strings representing the two positions and processing them into the correct arguments for the Haversine algorithm.
For the distance function that is given only one position, it acquires the other using the private GetCurPos function in the class. Once both strings are acquired, the private parse method is used to pull out the latitude and longitude of the point. The parse method converts the longitude and latitude represented in each string into two signed doubles that represent the position in decimal degrees. Enhancements and Future Work The communication between the DistanceCalculator class and the ListenGPS component is currently handled using file I/O. Other Resources. Vincenty ellipsoidal formula for geodetic distance between two Latitude/Longitude points in JavaScript | Movable Type Scripts.
For the benefit of the terminally obsessive (as well as the genuinely needy), Thaddeus Vincenty (‘TV’) devised formulae for calculating geodesic distances between a pair of latitude/longitude points on the earth’s surface, using an accurate ellipsoidal model of the earth. When I looked up the references (‘Direct and Inverse Solutions of Geodesics on the Ellipsoid with application of nested equations’), I discovered to my surprise that while the mathematics is utterly beyond me, it is actually quite simple to program. Vincenty’s formula is accurate to within 0.5mm, or 0.000015″ (!) , on the ellipsoid being used. Calculations based on a spherical model, such as the (much simpler) Haversine, are accurate to around 0.3% (which is still good enough for most purposes, of course).
Note: the accuracy quoted by Vincenty applies to the theoretical ellipsoid being used, which will differ (to varying degree) from the real earth geoid. Vincenty’s formula as it is used in the script: Where: Notes: Usage: Calculate distance between two points on a globe. Haversine Formula[edit] The haversine formula is an equation important in navigation, giving great-circle distances between two points on a sphere from their longitudes and latitudes. It is a special case of a more general formula in spherical trigonometry, the law of haversines, relating the sides and angles of spherical "triangles". Implementations[edit] APEX Force.com[edit] Java[edit] Objective C[edit] Perl[edit] # $lat1 and $lon1 are the coordinates of the first point in radians # $lat2 and $lon2 are the coordinates of the second point in radians my $a = sin(($lat2 - $lat1)/2.0); my $b = sin(($lon2 - $lon1)/2.0); my $h = ($a*$a) + cos($lat1) * cos($lat2) * ($b*$b); my $theta = 2 * asin(sqrt($h)); # distance in radians # in order to find the distance, multiply $theta by the radius of the earth, e.g. # $theta * 6,372.7976 = distance in kilometres (value from PostgreSQL PL/PERLU[edit] Query that returns nearest 10 locations within 25 km.
C++[edit] Python - GIS Wiki | The GIS Encyclopedia. From Wiki.GIS.com Python is a general-purpose high-level programming language, designed to be easily read. Python runs on Windows, Linux/Unix, Mac OS X, and has been ported to the Java and .NET virtual machines. [1] [edit] Python compared to other languages Python is said to be much shorter than other scripting languages such as Java and C++, but it requires longer run time, which can slow things down in large programs. Python's code is much more flexible as far as syntax goes compared to these "lower-level" languages. Many sources say that Python is 3-5 times shorter than Java and over 5 times shorter than C++.[2] There is no definite say on which program is better. "Python can be written quickly and maintained easier than Java. " [edit] Python in ArcGIS Python was introduced to ArcGIS with version 9.0. ESRI recommends using the version of Python (and additional packages) shipped together with the specific version of ArcGIS.[5] [edit] Python support in different versions of ArcGIS.
QML. Height Map Editor Home. Marine > AIS > AIS Information > AIS Decoder. Marine Weather. Wms - Use OpenLayers WMSGetFeatureInfo on Mapserver Layer. I'm able to use OpenLayers' OpenLayers.Layer.Mapserver declaration to generate a raster from GRIB data. I've read in the MapServer docs and on forums that it should be possible to get point information back from the raster using OL's WMSGetFeatureInfo. I've tried a few combinations of others' reported solutions. However, as the control is for a regular WMS and also nearly all of the solutions involve GeoServer, I've pretty much reached a wall. So this is my code: And my mapfile (some url and file locations changed for privacy, but not necessary for this question) MAP NAME "testgrib" IMAGETYPE PNG EXTENT -14000000 3000000 -7000000 7000000 STATUS ON SIZE 2145 1377 SHAPEPATH "..
And I need template files here for the response: test_header.html <! Test_body.html <body> band1: [value_0] </body> test_footer.html I'm not positive that the test_body.html is correct. Javanmeaparser - Java NMEA Parser. Extracting data from grib file based on latitude and longitude. Java-tide-engine - Provide the back end services for tide calculation. There is NO Graphical UI in this project.