gis

Converting Coordinates between custom Transverse Mercator and WGS84 Lon-Lat

Hi, I'm trying to put a bunch of (x,y) points on a map, that have a lon-lat origin. I'd like to set up a custom Transverse Mercator projection, centred on my origin, and use that to project my points into lon-lat. This seems like the sort of thing that GeoToolkit (or GeoTools) should be able to do, but I'm having great difficulty in de...

Need recommendation for ArcGIS Engine,ArcGIS Server and ArcSDE interview question.

Hi guys, I am preparing for GIS interview.I am looking for good ArcGIS Engine,ArcGIS Server and ArcSDE interview questions. I just googled some,but the questions that I found are not that much detailed to the technology. Can anyone recommend me something ? ...

Commercial Mapping software - South Africa

Hi, I am looking for a good quality and reliable mapping solution for South Africa. We require similar functionality to Bing and Google. ie plotting markers on the map, geocoding, drawing polygons, popups on the map showing content etc. So far Google maps looks like the winner, but are there other options that you would recommend. th...

java gis library

What is the best/user friendly GIS/arcGIS Java library for basic academic assignment? ...

How to find relation between change in latitudes at centre of map and top/bottom

Hi, Im having little trouble finding a relation between the movement at centre and edge of a circle, Im doing for panning world map,my map extent is 180,89:-180,-89, my map pans by adding change(dx,dY) to its extents and not its centre. Now a situation has arrrised where I have to move the map to a specific centre, to calculate the chan...

MySQL GIS Lat/Lon to X/Y: which is which?

Is there a convention for whether GIS points in MySQL should be stored as POINT($latitude $longitude) or POINT($longitude $latitude)? Having longitude correspond to X on a cartesian map would visually make more sense with north pointing up, but common parlance is to say "latitude and longitude." ...

Distance Between GIS Points

I have a large number of GIS (latitude, longitude) coordinates, and I'd like to get the distance between them. Is there a service that will calculate the shortest path for me? I know about google maps, but I'd like something I can use from Python, and that can handle a large batch of requests at once. I'm looking for the driving distanc...

How can I create set of small bounding boxes given a large area?

Given a large bounding box (say 1 km square), I want to divide this area into a set of smaller bounding boxes to form a grid pattern. I know there are some Earth geometry issues to contend with where. Can anyone help? I'm doing with with Ruby and I'm working with the excellent GeoKit library. Thank you! ...

finding distance between two UK addresses

Hello; I need to write an application which is to calculate the estimated driving distance between two UK addresses; I think I can use Google as following: http://maps.google.com/maps/nav?q=from:London%20to:Dover However, anyone knows what is the daily/monthly limit of querying the database from a single IP address? I need to impleme...

How to transform coordinate from WGS84 to a coordinate in a projection with PROJ.4?

I have a GPS-coordinate in WGS84 that I would like to transform to a map-projection coordinate in SWEREF99 TM using PROJ.4 in Java or Proj4js in JavaScript. Its hard to find documentation for PROJ.4 and how to use it. If you have a good link, please post it as a comment. The PROJ.4 parameters for SWEREF99 TM is +proj=utm +zone=33 +ellp...

How can I display characters in a map by mapfile?

Hello. I'm trying to show a map using postGIS+Mapserver. And I've displayed a PNG picture in my WEB. However, I want to show some charactors in the map, just like this: this is the example from Mapserver Now I'm using database(postgreSQL), but not a shape file. How can I add the charactors then? Here is a part of my mapfile: LAYER ...

Guidelines for LBS Mobile application development

i need some help!, i am planning to develop such LBS Mobile Application which find nearest things based on gps data from mobile. 1.what are the best free and (preferably) open source technologies for development?. 2.What programming language to use for development of such application?. 3.what are the points to be considered? I need t...

Getting a handle on GIS math, where do I start?

I am in charge of a program that is used to create a set of nodes and paths for consumption by an autonomous ground vehicle. The program keeps track of the locations of all items in its map by indicating the item's position as being x meters north and y meters east of an origin point of 0,0. In the real world, the vehicle knows the loc...

Algorithm to determine which points should be visible on a map based on zoom

Hi! I'm making a Google Maps-like application for a course at my Uni (not something complex, it should load the map of a city for example, not the whole world). The map can have many layers, including markers (restaurants, hospitals, etc.) The problem is that when you have many points and you zoom out the map it doesn't look right. At th...

How do I convert a latitude/longitude pair into a PostGIS geography type?

I'm trying to load a bunch of latitude/longitude pairs into a PostGIS geography type so as to be able to query by location. In particular I have a table with float latitude and longitude columns and a geography(Point, 4326) column. I would like to do update mytable set geography = ??? The documentation appears to suggest that the fo...

Do I need a spatial index in my database?

I am designing an application that needs to save geometric shapes in a database. I haven't choosen the database management system yet. In my application, all database queries will have an bounding box as input, and as output I want all shapes within that database. I know that databases with a spatial index is used for this kind of appli...

Alternatives to Google Earth for sat image

I've been asked to add Google Earth images to a desktop app (civil engineering modelling app) I was under the impression that Google's license didn't allow you to do this. Are there any other easily accessible, and similarly high resolution, image sources anyone can recommend (Blue Marble, terraserver) ? As a bonus, any library that le...

Accessing local map data with AppEngine

I'm creating an app with AppEngine (Java) that needs access to local map information. In general, I'd like to search any query such as: gas stations, cheap restaurants, banks, or whatever in a certain area. What is the best way to do this, and with which Service or API ? ...

In the UK, how do I find an address given the GPS coordinates?

Sorry this is not a very well defined question, I am thinking about an idea for a product, so need to know what is possible... Say I am standing at the fount door of a house, given the GSP coordinates from a smart phone, how can I find the address I am standing at? Is GPS good enough for this? How much does the data/service I need to ...

Web-based map authoring with ArcGIS Server?

I'm embarking on a project in which users will author, save, and share their own maps over the web. We will provide them with a large number of feature classes, but users will effectively author their own maps, map symbologies, etc. Furthermore, they will create and edit their own feature classes, which they can both map and share with o...