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17 votes
3 answers
5k views

Is there a decent open source map-editor?

I would like to have an open source map editor for drawing a city map? I don't want to use OpenStreetMap. It will be a custom map project. I don't need an advanced GIS system, but a simple map-editor,...
Jonas's user avatar
  • 2,231
25 votes
6 answers
17k views

Is GPS more accurate on specific hours of the day?

I have heard that the GPS system is more accurate, and less accurate on some specific hours on the day. If this is true, how can I get the information on when GPS is more or less accurate at my ...
Jonas's user avatar
  • 2,231
9 votes
4 answers
20k views

What data is sent from GPS satellites to receivers?

I know more or less how the GPS system works. But I would like to understand it in more details. Exactly what data is sent from a GPS satellite to a GPS receiver? I think there is multiple types of ...
Jonas's user avatar
  • 2,231
26 votes
3 answers
7k views

Simplifying adjacent polygons using PostGIS?

I encountered a problem simplifying set of polygons that are adjacent. If I simplify each polygon separately with the Douglas–Peucker algorithm (which is used by many open source tools), the resulting ...
stachu's user avatar
  • 851
17 votes
5 answers
5k views

Simplifying polygons to linestring?

I would like to simplify some polygons that represent rivers into linestrings. I assume that holes in polygons can be omitted. Anybody has some good idea how to simply do it? It would be nice, if it ...
stachu's user avatar
  • 851
5 votes
1 answer
619 views

Can someone explain in simple terms the licence on Google “satellite” images? [closed]

What can I and can I not do with the Google satellite images?
Ian's user avatar
  • 549
8 votes
2 answers
1k views

How does a quad-tree cope with very large objects?

If I use a quad-tree to index my map data, how does it cope with a road that goes from one end of the map to the other? What other sort of indexes should I consider to get round this problem?
Ian's user avatar
  • 549
3 votes
3 answers
248 views

What are the licence limitations on the free Ordnance Survey (OS) data sets?

The OS has some “free” map data, but what am I allowed to use it for?
Ian's user avatar
  • 549
4 votes
4 answers
395 views

Are there any other providers of map data in the UK apart from the Ordnance Survey?

The Ordnance Survey charges a lot for most data, so what are the other options?
Ian's user avatar
  • 549
4 votes
4 answers
970 views

In the UK, how do I convert from an address to a lat/long?

Please include where I can buy the dataset and how much it costs?
Ian's user avatar
  • 549
9 votes
5 answers
405 views

Tools for (semi) automated woodland tracing from satelite images

I'm trying to draw woodlands in OpenStreetMap, using Yahoo sattelite images. JOSM editor has some plugins that try to automate the process - you have to click inside the area and the plugin finds the ...
extropy's user avatar
  • 193
33 votes
9 answers
1k views

News resources for GIS community?

I currently rely on a mixture of mailing lists, twitter and a couple of blogs. What do you use for your GIS media intake, and why?
5 votes
3 answers
591 views

What is the GeoCloud

Directions Magazine, Pitney Bowes (MapInfo), and many blogs are talking about 'Cloud' in relation to GIS. I have read about Cloud-Computing but still don't understand the concept. What is the ...
user158's user avatar
  • 95
2 votes
5 answers
2k views

Hiding layers in mapfile (Mapserver) from WMS requests

We have a Mapserver mapfile used in a web app with a lot of layers. We want to publish only some of them with WMS, keeping the others hidden to any WMS request. It has to be the same mapfile and we ...
Javi Mollá's user avatar
38 votes
21 answers
35k views

Connecting to PostGIS database from ArcMap for display and query without ArcSDE?

How can I connect to a PostGIS database from ArcMap using ArcGIS Desktop 9.3 and later? I would like to be able to perform spatially enabled queries and receive the results back (e.g. spatial and non-...
fmark's user avatar
  • 9,381
7 votes
2 answers
2k views

Allow multiple users to share personal geodatabases safely?

We're using ArcGIS 9.3 but for reasons beyond the scope of this question we have to stick with personal geodatabases (MS Access .mdb's) and multiple users. How can we set this up so only a limited few ...
matt wilkie's user avatar
  • 28.2k
18 votes
11 answers
805 views

Seeking conferences for Spatial/GIS developers?

What are good conferences for GIS and spatial developers to attend? For Esri desktop users I think the User Conference is a must attend, but if you are an Esri developer I think the Esri developer ...
4 votes
5 answers
3k views

How can I print a bunch of Arcmap mxd's all at once?

I have a folder with a dozen Arcmap compositions (.mxd files) I need to print. They're all ready to go, I don't need to do any editing. Do I really have to open up each one, wait to refresh, and press ...
matt wilkie's user avatar
  • 28.2k
12 votes
2 answers
1k views

Can ArcGIS and OSGeo4W share the same python install? [duplicate]

I don't like unnecessary duplication. Is it possible to install python only once and have both ArcGIS and OSGeo4W using it?
matt wilkie's user avatar
  • 28.2k
28 votes
3 answers
12k views

What is difference between ArcSDE and spatially enabled databases?

When would you want to use ArcSDE (available as ArcGIS Server Basic license level) versus a spatially enabled database? What are the trade-offs on either side? What are the benefits on either side?...
TheSteve0's user avatar
  • 2,324
21 votes
3 answers
4k views

What are the differences between spatial databases? [closed]

What is the difference between Oracle Spatial, PostGIS, SQLServer2008, SpatiaLite, and MySQL in terms of their spatial support. Are there specific use cases where each shines. What might you want to ...
TheSteve0's user avatar
  • 2,324
2 votes
4 answers
16k views

Calculating length and area with Google Maps API? [closed]

Google Maps API v2 had great methods for lines and polygons to calculate length and area. v3 is lacking these methods (maybe just for now?). What other options do I have for calculating line length ...
Jason's user avatar
  • 708
10 votes
3 answers
6k views

Make the nodata area of a resampled orthophoto overview white?

I have a set of orthophoto images which are each fully filled with data, but when placed together the coverage does not form a rectangle so there are nodata areas. In MapGuide, I need to be able to ...
JasonBirch's user avatar
  • 2,032
0 votes
0 answers
501 views

IronPython + ArcObjects

Is it possible to access ArcObjects with IronPython?
George Silva's user avatar
  • 6,310
18 votes
4 answers
4k views

Are ArcGIS *.lyr and *.mxd data format specs published?

Are the binary formats of *.lyr and *.mxd files published?
Scott Wisniewski's user avatar
114 votes
23 answers
143k views

Converting between KML and shapefile (SHP) format

My users are sending me point data that were digitized using Google Earth. How can I convert their KML to a shapefile and vice versa?
TroutSlayer's user avatar
  • 1,363
29 votes
3 answers
49k views

What are the major differences between GPS, GLONASS and Galileo? [closed]

What are the major differences between GPS, GLONASS, COMPASS and Galileo?
JamesRyan's user avatar
  • 951
21 votes
9 answers
37k views

Choosing database for storing spatial data?

A couple of days ago I installed the demo of spatialware 4.9 from MapInfo into my SQL Server 2005 install and loaded all the larger dataset into it. I was quite impressed with the performance vs the ...
Nathan W's user avatar
  • 34.8k
20 votes
8 answers
28k views

How can I determine the location of a visitor to my website?

If I want to provide a website with location appropriate content, what ways can I use to find the visitor's rough location using their IP or header information?
JamesRyan's user avatar
  • 951
5 votes
5 answers
389 views

What is the best way to protect data online?

What techniques do people use when protecting data (e.g., preventing a user downloading the whole dataset) they are overlaying on top of Google/Yahoo/Bing etc.?
Jx2000's user avatar
  • 61
38 votes
4 answers
13k views

Separate polygons based on intersection using PostGIS

I have a PostGIS table of polygons where some intersect with one another. This is what I'm trying to do: For a given polygon selected by id, give me all of the polygons that intersect. Basically, ...
atogle's user avatar
  • 1,742
4 votes
2 answers
984 views

Authentication with ArcGIS Server Identity

Just getting back into ArcGIS for .NET again after about 2 years of doing the training course. I have a question about the "Add ArcGIS Identity" that you choose in Visual Studio - it doesn't seem to ...
Vidar's user avatar
  • 1,870
143 votes
5 answers
29k views

Accessing ArcObjects from Python

I would like to be able to script some things that are not exposed via arcgisscripting or ArcPy. How do I access ArcObjects from Python?
matt wilkie's user avatar
  • 28.2k
3 votes
3 answers
897 views

Verifying that ArcInfo Workstation is Installed? [closed]

What is the best way to verify that a machine has ArcInfo Workstation installed? A code sample in VBA, VB or C# would be great!
Robert Claypool's user avatar
2 votes
5 answers
3k views

Is there any open source library for reading OCAD files?

I would like to read map files created by OCAD (.ocd). The file format specification is open and available on the web page, but it's binary and complex. Is there an open source library that can be ...
Jonas's user avatar
  • 2,231
45 votes
6 answers
62k views

Trilateration using 3 latitude/longitude points, and 3 distances?

I want to find out an unknown target location (latitude and longitude co-ordinates). There are 3 known points (latitude and longitude co-ordinate pairs) and for each point a distance in kilometers to ...
nohat's user avatar
  • 555
16 votes
8 answers
685 views

Are there sources for more esoteric data than streets worldwide?

Related to this question. For example, things like: political world map (as polygons) cities of the world geolocated climate data (avg temp, humidity, rain, as polygons), earthquakes, hurricanes (as ...
7 votes
5 answers
254 views

What datastructure is a good choice for objects in a map-editor?

I am planning to implement a map-editor. But I don't really know what data structure is a good choice for storing the map-object in. When the user pans (scrolls) the map, there will be much looking ...
Jonas's user avatar
  • 2,231
29 votes
9 answers
7k views

Is there any way I can use a Key-Value store for geospatial data?

I have used many relational databases in the past, but I have also read about all NoSQL databases, and the Key-Value stores looks interesting. When I store geometric object I mostly use five indexed ...
Jonas's user avatar
  • 2,231
3 votes
1 answer
881 views

Setting toolbar server control currenttool to none with ArcObjects and ArcGIS Server?

I am only using the map control and two toolbars on a custom webadf application. One toolbar contains the standard map navigation controls. The other toolbar is only one toolitem which references a ...
shawn deutch's user avatar
27 votes
6 answers
23k views

What tools in Python are available for doing great circle distance + line creation?

I need to use Python to create a great circle distance -- both a number, and preferably some kind of 'curve' that I can use to draw in a client-side map. I don't care about the format of the curve -- ...
Christopher Schmidt's user avatar
9 votes
6 answers
21k views

Can you make a travel region polygon with with Google Maps API? [closed]

I am working on a local design project and need to determine if someone is local to my area to allow them to participate. Local, as defined by the group, means that the person is within 2 hr driving ...
GuidoS's user avatar
  • 1,174
40 votes
15 answers
120k views

Converting MapInfo TAB and/or MIF to SHP using free tools or ArcGIS for Desktop core product?

How do I convert MapInfo TAB and/or MIF files to SHP using only free tools or ArcGIS itself? I've not had much luck trying to do this in the past and I don't want to have to shell out for the ArcGIS ...
Charles Roper's user avatar
13 votes
6 answers
94k views

Seeking Canadian postal code geometries

Where can I find the shapefiles for Canadian postal codes?
25 votes
5 answers
3k views

Simplifying geometries (generalization)

What are the recommended ways of simplifying geometries? Keeping in mind projections, and simplifying state geometries, for example. I've heard about converting to an 'equi-distant' projection that ...
John Weldon's user avatar
22 votes
3 answers
2k views

Where to get street data in an importable format?

I don't want to use WMS layers, but to actually store the data in my local server, where can I find street data from the world?
Vinko Vrsalovic's user avatar
17 votes
1 answer
2k views

Seeking embeddable web-based maps

Some of the ones I'm familiar with (in no particular order): Google Maps (http://code.google.com/apis/maps/index.html) Bing Maps (http://www.microsoft.com/maps/developers/) Yahoo Maps (http://...
58 votes
11 answers
51k views

Seeking Free and Open Source GIS Desktop packages?

Can someone give me a list of free and open source GIS desktop packages?
12 votes
4 answers
14k views

Ordnance Survey grids - download or generate?

Does anyone know a source from which to download vector UK Ordnance Survey grids at varying resolutions? Or failing that, a tool that can create an OS grid at a specified resolution? There are plenty ...
Charles Roper's user avatar
11 votes
3 answers
2k views

Where can I get data for traffic signals, stop signs, and other sign assets/inventory?

I'm working on a project involving roads. The quality of the service would benefit from knowing if a given road is continuous or if it's broken up by stop signs, traffic signals, and other things ...
Eric Palakovich Carr's user avatar

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