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
7k 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?
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

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
7k 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
797 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
6k 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
3answers
930 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
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:
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 ...
7
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 ...
3
votes
1answer
304 views

Calculate line distances inside of polygon

I'm working with two data sets: NHD polyline stream layer for my entire state HUC Watershed boundary Polygons for the entire state I am looking for a way to calculate the total length of streams ...
3
votes
1answer
782 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
3answers
895 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
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:// ...
18
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 ...
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
5answers
55k 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
8k 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) ...
16
votes
7answers
13k 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 ...
20
votes
3answers
12k views

How to convert ArcGIS .mxd file to QGIS .qgs file?

I recently tried to use QGIS and I wondered if you can convert a draft ArcGIS map (*.mxd file) into a QGIS project (*.qgs file). This would avoid thematize the entire project.
20
votes
1answer
5k views

Is WGS84 itself a Coordinate Reference System?

I was wondering the difference between WGS84 and EPSG:4326 (see this). Can then WGS84 on its own be defined as a Coordinate Reference System? Or is it just a datum so that a Coordinate System must ...
19
votes
4answers
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
7k 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 ...
13
votes
3answers
5k views

How to join attributes from nearest point in QGIS?

I have two layers with points, call them A and B, each with different attributes. For each point in A I want to join all the attributes from the nearest point in B. Ideally this would also include ...
11
votes
4answers
2k 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 ...
18
votes
4answers
14k views

How do I load OSM vector data in QGIS 2.x?

In QGIS 1.8 I used the openstreetmap plugin to request data from the server, or open a .osm XML file, which produced 3 layers (polygons, polylines and points) in QGIS. This was great (give or take the ...
17
votes
7answers
4k views

Creating trade flow maps in ArcGIS for Desktop (or any free software)?

I am trying to represent trade flows on a world map where the size and direction of arrows indicate the exports/imports of a given country. This type of map is commonly found in magazines and ...
15
votes
3answers
3k views

Visual Impact Assessment in QGIS or GRASS

Is it possible using QGIS or GRASS to perform a Zone of Visual Impact assessment? E.g. where can a 100m high structure be seen at a viewing height of 1.8m within 30km, taking into account elevation ...
11
votes
6answers
5k views

ESRI ArcMap Add-in with app.settings not recognizing app.config changes

I have an ESRI Add-in developed for ArcMap which requires a configuration file. After spending a while trying to read config values from a single App.Config file (and always getting null) I believe ...
27
votes
3answers
23k views

What is the difference between WGS84 and EPSG4326?

What is the difference between WGS 84 and EPSG 4326? It seems like for a given dataset it might be both WGS 84 and EPSG 4326.
19
votes
4answers
6k views

Maximum number of point features in an OpenLayers vector layer

In your experience, how many point features can be added to an OpenLayers vector layer (new OpenLayers.Layer.Vector("Point Layer")) before it goes unusably slow? My use case is to display points from ...
15
votes
9answers
23k views

How to install QGIS on Ubuntu 12.04?

Has anyone had any luck with getting QGIS working on Ubuntu 12.04? I have tried the stable and unstable versions and with not luck. I also get the following: "Some packages could not be installed. ...
12
votes
4answers
2k views

Comparing two Digital Elevation Models (DEMs) from LAS files?

I have two Lidar las files, one is original let's say with X points. And the other is copy of the first las file but with Y points, where Y is less than X. Now, I want to compare how the Digital ...
10
votes
3answers
15k views

How to convert .shp to .csv including attributes AND geometry?

I have a .shp file with 60k+ entries, all of which are polygons with corresponding attributes (acreage totals, landowner names, tax ID #s, etc.). What I ultimately need is a .csv file with all of ...
6
votes
1answer
768 views

How to do a separate Python installation with ArcGIS?

I see a lot of threads asking how you can have a separate Python installation (e.g. the Anaconda or Python XY distribution) and get it to work with arcpy, while not 'breaking' ArcGIS at the same time. ...
26
votes
4answers
14k views

Which character encoding is used by the DBF file in shapefiles?

Which character-encoding is used by the dbf-file in Shape-files? It seems it is handled different, based on the program and the local encoding-settings of the machine. Which encoding is 'right' - ...
18
votes
8answers
12k views

Where to get 2010 Census Block data?

This might be a stupid question but I would like to download 2010 Census Block Data for several towns and I can't seem to find it on American Factfinder. Is it there? And if not, does anyone know ...

15 30 50 per page