10
votes
1answer
1k views

Is there a way to access QGIS plugins in Python?

Is there a way to access QGIS plugins in Python? I'd like to write a script to do some geoprocessing, and I'd like to use the clip, regular points and convex hull tools in fTools, as well as the Road ...
8
votes
1answer
2k views

Sort layers in QGIS table of contents?

When I load a bunch of layers into QGIS from PostGIS, they seem to load in reverse alphabetical order. Is there any tools or plugins that allow you to quickly sort the QGIS TOC in a different order? ...
8
votes
2answers
2k 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 ...
8
votes
3answers
3k 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
3k views

How to write standalone Python scripts using QGIS?

I've been learning how to use the Python Console in QGIS using references from qgisworkshop.org. I'm familiar with writing standalone scripts in ArcGIS and want to learn how to do the same with QGIS. ...
6
votes
1answer
1k 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
3answers
7k 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?
14
votes
2answers
3k views

Performing Raster Noise Reduction and Edge Smoothing?

I have a raster image like this I want to delete the isolated noise point and smooth the edge (say the white single points, and I want the edges of the entity look smooth). How can I do this in ...
10
votes
3answers
3k views

How to programatically check for a mouse click in QGIS

I want to know how to check for a mouse click in QGIS. I am trying to write a python plugin and want to provide functionality similar to the "Select Single Feature" tool that already exists in QGIS. ...
7
votes
5answers
5k views

Looking for advanced GeoServer tutorials

What are sources where I can learn how to use GeoServer? I know of these two sites: http://geoserver.org/ - which in fact is not working (at least at the moment) ...
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
3k views

How to read Greek fonts (ISO-8859-7) in shapefile attributes within QGIS 1.8.0?

I'd like to ask whether there is a way to read greek fonts in a shapefile's attribute table within QGIS 1.8.0.
6
votes
1answer
11k views

How to crop Shapefiles in QGIS?

I need to clip a large and very detailed .shp file in QGIS showing environmental data similar to a temperature map. Is there something like the very simple crop tool alike in photoshop where you can ...
5
votes
3answers
8k views

Remove spatially duplicate features using ModelBuilder

I am creating a model to remove features which are duplicated within a polygon feature class. Most of the features are duplicated once, but about a quarter have up to three or four exact copies. I do ...
3
votes
2answers
1k views

Simple automated way to split all lines in layer at vertices using QGIS?

I want to automatically split all lines in a QGIS layer at their vertices (like this). I've done a google search and found this article, which is quite close but the workflow is complicated. Because ...
12
votes
4answers
5k views

free GIS software that can orthorectify?

Would someone care to recommend a free and/or open source GIS application that can orthorectify map images?
6
votes
3answers
5k views

How to Partition Line into Segments using ArcGIS for Desktop?

I have a shapefile of U.S. states. I extracted the boundary between two states, resulting in a line segment. For example, the boundary between Georgia and North Carolina. Is there a way to further ...
6
votes
2answers
8k views

How to calculate polygon areas and perimeters using QGIS?

Using QGIS, if I load a polygon layer and make a new column, how do I fill that column with the: area of each polygon and another column with length of the perimeter of each polygon?
6
votes
3answers
6k 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
8k 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
811 views

Identify the latitudinal and longitudinal point directly beneath an object in space

Given the azimuth and altitude / latitude and longitude from the observer to the satellite, how can I accurately find the latitude and longitude of the point of intersection directly under the ...
3
votes
2answers
7k 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 ...
2
votes
2answers
126 views

How to use QGIS explode lines with Python

I want to access the explode lines function in Python outside of QGIS from a standalone script. What module do I have to load in order to use it? How can I access processing? from qgis.core import * ...
2
votes
3answers
1k views

How to auto increment a field in a feature class?

So I'm relatively new to ArcGIS and ArcCatalog. I have created a field name of PROJECTID in a feature class in a Personal Geodatabase. The data type is TEXT. This will be a ten digit ID. The first ...
2
votes
3answers
988 views

Data-defined Styles in QGIS

I have downloaded a shapefile of bedrock geology. I need it to be displayed as it should be with the style applied. The supplier will no give me a qml. but i have noticed in the .dbf file the Cyan ...
2
votes
3answers
2k views

Local Coordinate to Geocentric

The ultimate question, I need a transformation matrix to take a point in local space representing a roughly 500m x 500m place in New Mexico centered at -108.619987456 long 36.234600064 lat. The final ...
2
votes
1answer
1k views

How to avoid duplicate labels on each tile?

When I display my map using tiles a label gets drawn on each tile - is there any way to avoid this? I have attached an example image to show the problem:
8
votes
1answer
5k views

Understanding QGIS buffer tool units?

I have been trying to figure this out for a couple weeks now and have had no luck getting the buffer tool to accept anything but degrees as units of measure. I have found lots of stuff saying the ...
7
votes
2answers
1k views

How to Refresh open attribute table in ArcMap using ArcPy rather than ArcObjects?

I am running the Calculate Field GP tool from the arcpy in ArcMap. When a row value is updated, it does not show up untill I use the Reload Cache tool (Table Options > Reload Cache). How do I refresh ...
5
votes
2answers
5k views

How to sort a feature class and then calculate a sequential ID field?

I am in ArcMap and I want to sort the records based on a field and then do a Calculate Field with an auto-incrementing value with the sort in-place. Any ideas? It looks like I could get an update ...
4
votes
1answer
830 views

How to style a layer from console?

I am new to the QGIS python console. I am trying to load a raster layer from the console, set the crs and a specific style from a qml file. layerPath = os.path.join(raster_dir,raster_name) fileInfo = ...
2
votes
1answer
4k views

XMLHttpRequest cannot load http://localhost: /geoserver/wfs. Origin http://localhost is not allowed by Access-Control-Allow-Origin [duplicate]

Possible Duplicate: Setup own Openlayers Proxyhost Error WFS Request, PROXY problems I have this error: XMLHttpRequest cannot load http:// localhost: /geoserver/wfs Origin http:// ...
1
vote
1answer
163 views

flatten / collapse one-to-many table and keep the 'many' attributes separate

I have a data set that contains intersection data. Each intersection node has up to 6 links which is identified by IN_LINK and OUT_LINK attributes. I want to create a new dataset that includes the ...
19
votes
11answers
4k views

What are the Python tools/modules/add-ins crucial in GIS?

With ArcGIS 10, Python has become the de-facto scripting language for ESRI. While leading Open source software like QGIS, GeoServer, PostGIS all supports Python. Thus it became important to know/learn ...
39
votes
4answers
2k 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 ...
22
votes
9answers
2k views

Good Symbology for Interactive Web Mapping

When a user clicks on a map what should they expect to see? I would say a symbol for where they clicked. A pushpin seems to be the most accepted icon for generic data. Google has pushed the upside ...
19
votes
9answers
6k views

How do I develop my GIS programming skills?

I would like to develop my GIS programming skills, where do I start? People say learn C++ or Python but where can I learn this in a geographic context? Tutorials or anything would be very helpful, as ...
30
votes
1answer
10k views

How to find the center of geometry of an object?

Well it might be a simple question. Given a set of 2D or 3D points, the question is: How to find the center of geometry of an object? According to the following figure, the center of geometry ...
31
votes
5answers
57k views

What are Raster and Vector data in GIS and when to use?

What are raster and vector data in the GIS context? In general terms what applications, processes, or analysis are each suited for? (And not suited for!) In answering someone's question today, I ...
28
votes
4answers
9k views

How to find the minimum-area-rectangle for given points?

The following is another problem that I am working on it these days. As you see in the figure, (BTW, I tried to make it self-presenter) the question is: How to find the minimum-area-rectangle (MAR) ...
17
votes
7answers
14k views

Is there an open source Geocoding tool which can be used commercially?

Is there any Geocoding tool which is open source and can be used in commercial application? We tried Google geocoding API's but cannot continue with it because of some licensing limitation. Now ...
19
votes
5answers
4k views

How to put GeoServer layers behind authentication?

I want to publish map layers using OpenLayers and GeoServer. While this is easy enough to set up, I'm a bit lost when it comes to authentication possibilities. What I want is to create different users ...
17
votes
8answers
5k views

When Versioning with ArcSDE can posted edits be cancelled or rejected?

I am using ArcGIS 9.3.1 and attempting to work with an SDE geodatabase (with one polygon feature class) that has already been registered as versioned. I'm new to versioning and am still trying to ...
15
votes
3answers
10k views

Mapnik, Mapserver or Geoserver

I'm currently developping an ArcGIS based flex webviewer. ArcGIS is great for most of the things but there are some issues like performance and license costs. That's why I'm looking into possible ...
14
votes
4answers
8k views

How to add an attribute field to an existing Shapefile via Python

I have a Python script that adds an attribute field to a Shapefile if doesn't exist. This is easy to do with ArcGIS (graphically or via Python), but I'm looking for something that doesn't depend on ...
13
votes
3answers
4k views

Converting SimpleGeo Places GeoJSON file to shapefile?

SimpleGeo has recently made their "Places" data set freely available which is GREAT, because now we can use it for our own purposes, even offline. So I went about downloading the 2GB dataset, which ...
11
votes
4answers
3k 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 ...
23
votes
7answers
1k views

What tools for regionalization/redistricting can you recommend?

I am looking for tools for regionalization / districting in GIS. So far I have been able to identify Districting ArcGIS extension (now also online) REDCAP (currently limited to 50k input polygons) ...
21
votes
5answers
4k views

Is there any model builder in QGIS or other open source GIS?

Like the ModelBuilder of ArcGIS for Desktop to run simultaneous geoprocessing tools, is there any model builder available in QGIS or any other open source GIS software?
19
votes
9answers
4k views

Are there any Indoor GIS platforms?

What sort of infrastructure is needed to allow me to write a simple mobile app for indoor navigation? Professor Mike Goodchild said: the average American only spends 13 percent of the time ...

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