12
votes
2answers
3k views

Using Geodesic Measurements for Circle Radii?

I am currently developing an OpenLayers mapping site. Measurements can be made using a line tool, and an area tool. Both of these are currently set to calculate geodesic measurements as outlined in ...
7
votes
1answer
500 views

How to reopen hidden panels in print composer?

I unfortunately deleted the menu (Qgis 1.8.0) in print composer (settings for labels etc) . Now I am wondering how to display it again? The menu is gone in all my projects and I could not find a ...
4
votes
2answers
2k views

Unable to create WFS successfully

I know there has been lots of WFS assistant and I did follow this one word by word, which I found was the best in the entire gis stack but still no clue why I am unbale to render a WFS on base map. ...
36
votes
7answers
3k views

Best practices for PostGIS production environments?

What PostGIS documentation have you come across that has been helpful when tuning PostGIS for a production environment? I would like to get together with my DBA to setup a Postgresql/PostGIS ...
27
votes
2answers
2k views

Acquiring ArcGIS-like speed in Postgis

I have been using Postgis 2.0 for 3/4 of a year now and while I really enjoy using it, excessive query processing time has rendered it basically unusable for my use case. I tend to do heavy ...
33
votes
7answers
8k views

Creating drive time polygons using open source tools

Is anyone using open source tools and/or data to generate drive time polygons that radiate out from a given location? For example, I have used ESRI products like Network Analyst and Business Analyst ...
55
votes
19answers
41k views

How to convert between KML and Esri's shapefile (SHP) format?

My users are sending me point data that were digitized using GoogleEarth. How can I convert their KML to a shapefile?
17
votes
3answers
985 views

Best practices for organization and tidiness - How do you deal with multiple copies of layers?

Back in the days when I was in the university I had a "Organization and tidiness" problem – I was unorganized and kept my layers in different folders without distinct names and hence had multiple ...
24
votes
9answers
2k views

Effectively displaying demographic data on a printed map

I would like to plot the following per zone (30 zones total) data on a printable/non interactive map: Average age Average household income Number of households Population density Number of people ...
23
votes
9answers
11k views

How can I connect to a PostGIS database from ArcMap 9.3 and 10.0?

How can I connect to a PostGIS database from ArcMap 9.3 or 10.0? Ideally, I would like to be able to perform spatially enabled queries and receive the results back (e.g. spatial and non-spatial ...
20
votes
3answers
1k views

How to represent trend over time?

I have a time series of rasters where the cells of each raster represents some value at a certain time. I'd like to generate a map that highlights the magnitude of positive or negative trends in this ...
16
votes
9answers
3k views

Getting started with Arcobjects

What is the best route or place to get started with arcobjects if one is not a developer and not aiming to become a developer? I've been using gis professionally for a long time, almost two decades, ...
16
votes
1answer
3k views

Trilateration algorithm for n amount of points

I need to find algorithm that can calculate centroid A (aka gravity center, geometric center, center of mass) from the figure where circles T1,T2,T3,T4,T5,..,Tn intersect AND length of line R from ...
20
votes
3answers
6k views

Most Up-To-Date Source for US Zip Code Boundaries

I was just wondering what the most up-to-date source for US Zip Code boundaries would be. My first thought was TIGER, whenever that comes out, but then I thought that the Postal Service might be a ...
19
votes
9answers
2k views

Discontinuous or Interrupted map projections?

Do any of the current open source GIS softwares support discontinous projection systems? E.g. sinusoidal, dymaxion, butterfly, etc? If not, are there any affordable commercial ones that do (affordable ...
11
votes
9answers
11k views

How to convert KML to shapefile without losing attributes?

I'm new to QGIS and all geoinformation itself but have to work on some difficult stuff. I have a KML file with hundreds of points. To each point there is information, such as Name, Power, Age (it's a ...
19
votes
3answers
1k views

Packing Polygons within polygon

I have a Boolean raster. In the grey areas of the raster I would like to fit a given size polygon within a contiguous extent. Basically, I have an irregular polygon, and i would like to "fit" a ...
13
votes
2answers
2k views

Calculate distortion outside a UTM zone

One of my colleagues is working with data that is spread across two UTM zone. The majority of the data is in one zone, with a few outliers in another zone. He would like to know what the area ...
8
votes
2answers
423 views

Create a summary table of the symbology of all datasets in multiple mxd's

This is related to the following Retain ESRI symbology in Mapinfo TAB . As an initial step (in arcpy) I want to access the symbology of all the datasets and create a document which has the details of ...
8
votes
6answers
2k views

Get a point on a polyline from end points given distance along poly line

I have start point and end point of a polyline. How can I get a point on that polyline from end points specified by the given distance. How can I get this by using arcpy provided that this script ...
32
votes
3answers
6k views

LatLon or LonLat, what's the “right” way to display coordinates and inputs?

I'm trying to get a sense if this is an issue for others or every input/output should be labeled so user is not confused and just go with it? I think almost everyone pronounces it as "LatLon". Who ...
20
votes
3answers
6k views

How to make a spatial view in PostGIS and add it as a layer in QGIS?

In PostGIS 2.0, what is the most efficient way to create a spatially enabled view that is viewable in QGIS? I followed the context of Part 2 of @Mike Toews answer to this question, and the view ...
9
votes
4answers
2k views

Code to calculate elevation profile along line from a DEM

Given a DEM (Digital Elevation Model) say in and a line (x1,y1) --> (x2,y2) (paired coordinates (x,y)), how can one calculate the elevation profile or cross-section projected on that line ? I am ...
17
votes
2answers
5k views

How to convert .shp into .gpx using QGIS?

I'm newbie using QGIS. I would like to convert .shp into .gpx. So, using Qgis, I open my shapefile and I tried to "save as" gpx but it gives an OGR error: creation of field ObjectId failed (OGR ...
15
votes
3answers
2k views

How do I find the distance between two coordinates in an ellipsoid?

Lets say I have two sets of latitude and longitude. How do I find the distance between the two locations if I assume the earth is a perfect ellipsoid (with an eccentricity of 0.0167)?
11
votes
3answers
6k views

list all feature classes in GDB, including within feature datasets

From python how can I build a list of all feature classes in a geodatabase, including inside feature datasets? The standard example only lists FC's at the top level of the gdb: import ...
7
votes
1answer
2k views

Is there an comparison of the various mapping libraries for Android?

I am currently looking at the various libraries that I can use to show a map in my custom Android App. I have found several like Mapsforge, OSMDroid, ArcGIS runtime for Android, Google Maps for ...
13
votes
2answers
3k views

How can I convert data in the form of lat, lon, value into a raster file using R?

I have a data set of values over a km grid in the continental U.S. The columns are "latitude", "longitude", and "observation", e.g.: "lat" "lon" "yield" 25.567 -120.347 3.6 25.832 ...
9
votes
2answers
1k views

How can I convert geomagnetic coordinates to geographic coordinates without doing the math myself?

I have some data which are in geomagnetic coordinates; that is, they are latitude and longitude, but in reference to the magnetic north pole in Canada rather than the geographic north pole. As you ...
8
votes
3answers
2k 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 ...
6
votes
1answer
918 views

Nearest Neighbor calculation in PostGIS

I'm learning how to use PostGIS and spatial databases for analysis. What I am trying to do is perform a calculation to get the distance for the nearest polygon in a file, using the edge calculation, ...
5
votes
4answers
2k views

How to split a vector in equal smaller parts in QGIS or similar?

i want to divide a shapefile with many tiles into a lot of smaller tiles. I am searching for a smart solution, because manual edits are out of questions Anyone can help or know a nice function?
5
votes
3answers
5k views

How to convert coverage (.adf) to shapefile?

Is there any tool or software except ArcGIS which I can use for converting coverage (.adf) files to shapefiles?
6
votes
1answer
3k views

How to add automate values to attribute field?

I have parcel, Buildings layers, without any information attribute table, and i want to replace "NULL" values with numbers form 1 to 2000, in "Parcel ID", or "Building ID" field thank you.
5
votes
2answers
4k views

Rotating a vector layer in QGIS with qgsAffine (or other method)?

I would like to rotate a set of vector points in QGIS an arbitrary number of degrees around a central point (or arbitrary point). This is similar to a recent question about creating a regular grid; ...
2
votes
2answers
4k views

Viewing .las format LIDAR data in QGIS?

Is there an easy path to visualizing this LIDAR data? I have QGIS, and some USGS LIDAR data in (.las) format downloaded from http://lidar.cr.usgs.gov/ . This means I have both the (.las) and ...
8
votes
8answers
14k views

How to import a DWG into a QGIS project?

I have a lot of DWG files like base map, and water and wastewater network. I am lookin for the principal steps to import my files into my QGIS project.
7
votes
3answers
322 views

How to apply the four colors theorem in a polygon map in ArcGIS/ArcToolBox automatcally?

I need to apply the four colors theorem in a polygonal shape in a way that I do not need to choose manually each color to put in each region. I wish to knows if there is any extension, plug-in, script ...
7
votes
2answers
1k views

Workflow for determining stream gradient?

As far as data goes, I'm working with NHD .shp files, 10m DEMs, and some LIDAR data. My goal is to determine gradient for 100m segments of a network of streams. I'm already able to do this, but I ...
7
votes
3answers
1k views

How to interpret GRASS v.kernel results?

GRASS manual reads: v.kernel - Generates a raster density map from vector points data using a moving 2D isotropic Gaussian kernel ... Ok, but how do I interpret the results? I understand that ...
6
votes
3answers
4k views

Programmatically start and stop map services with Python

Is it possible to programmatically stop and start ArcGIS Server map services using Python?
6
votes
4answers
6k views

How to reproject base layers in OpenLayers?

The issue is: I have vector/topo/image tiled maps for some places in north america which were published as ArcGIS Server REST service. These maps (A) are based in EPSG26912 projection. Now I wanna ...
5
votes
2answers
2k views

How to add links to PDFs in a Shapefile?

I have a problem. I want an attribute in a shape file named "Link" to add. The works are all fine. But then I would like to add a link in my directory. This link accesses a PDF. Now, this PDF is not ...
3
votes
2answers
4k views

How to Extract by Attribute Using ModelBuilder with User Input?

Using ModelBuilder, I want to create a tool that will let a user choose the value or values that will be used to extract a shapefile. I have a parcel layer with a "Parcel_Type" field. I want the user ...
7
votes
2answers
5k views

How to reproject a vector layer in QGIS?

I have some shape file which is in UTM. I wanted them to convert to Decimal Degrees in QGIS. Thanks.
36
votes
4answers
1k views

What are the FOSS equivalents to these ArcGIS products?

I'm a long-term user of ESRI software, and I now have a need to use free and open source software. I've been reading about Open Layers, PostgreSQL, PostGIS, GeoServer and MapServer but I can't find ...
33
votes
21answers
33k views

Are there any free administrative boundaries available as shapefiles?

After learning about the US Census's TIGERLines datasets I'm addicted to GIS :) I've working with the following layers, from the USA data Country boundaries State boundaries County boundaries City ...
23
votes
5answers
5k views

Comparison of the different open source GIS servers

I currently know the following open source GIS servers: Geoserver: java based, vector and bitmap support, also supports. Is now on par with mapserver (performance-wise). mapserver: c/c++, used to be ...
31
votes
6answers
6k views

Downloading OpenStreetMap Data

Is there a straightforward way to download data from OpenStreetMap (OSM)? Using North America as an example, I realize Cloudmade (http://downloads.cloudmade.com/north_america) and geofabrik ...
17
votes
2answers
3k views

Visualize shapefile in Python

I was searching the internet to see if it is possible to visualize geographical data in Python, without always opening ArcGIS and make a map (because I have a lot of scripts that uses arcpy). On the ...

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