0
votes
1answer
832 views

How to calculate surface area of highland region using DEM with ArcGIS (ArcEditor)? [duplicate]

Am shyaka from Rwanda. I use GIS tools and have all required data to perform or calculate surface area from the polygons that have been given by GPS (Trimble) with ArcPad 8. I originate from a high ...
2
votes
1answer
167 views

How to save after using fet.setFeatureId in pyQGIS?

By using the following code, I want to change the id of the line when saving the line. But the setFeatureId command, gives a false when doing the commitChanges(). Any idea how to change the id? vl = ...
1
vote
0answers
92 views

proportion of image layer in OL

I tried create map with single image used OL. But I have a trouble: image in map has a wrong proportions. Img: 1540 x 1481 Img in map: 2858 x1481 My js code: $(function (){ var map = new ...
4
votes
2answers
350 views

How to write an equivalent to MapBasic's CreateLine in pyQGIS?

I know this kind of question has been asked, in part, before - specifically: Seeing QGIS Python Commands and: How is object created as line using createline stored in .tab file? but this is a specific ...
2
votes
1answer
2k views

Incorrect field name resulted in RuntimeError: ERROR 999999 (Also, better code for adding and calculating fields)

This is the bottom half of my code (and it's been edited somewhat to share publicly). The code works perfectly fine when the fieldList has only three fields in it, but when I populate it with all 108 ...
1
vote
1answer
633 views

How to store selected attributes of vector layer using PyQGIS

I'm following this PyQgis workshop: http://www.qgisworkshop.org/html/workshop/python_in_qgis_tutorial2.html#accessing-data-attributes I have a point layer shapefile. I want to be able to retrieve and ...
1
vote
5answers
3k views

export 3D data dxf file

I'm trying to export a DXF file from Qgis1.8.0 Lisboa and can not have a 3Dfile in Autocad! Or micristation. It results always in 2D file. How can I export height data from a shape file in Qgis? ...
5
votes
1answer
1k views

Varying Line Widths According to Attribute Values

I'm trying to draw a vector map of Europe on QGIS 1.7.3 with lines symbolizing the transmission of energy (power transmission lines) between the different countries on the map. I am trying to ...
0
votes
0answers
129 views

'D8 Slope Grid' in Sextante-QGIS is not working

I can't make 'D8 Slope Grid' work in QGIS-Sextante. 'Pit Filled' and 'D8 Flow Direction Grid' output work okay. I used the function: Geoalgorithms > Uncategorized > Basic Grid Analysis tools > D8 ...
2
votes
1answer
883 views

call child div function from parent (not using window.opener)

This is a a Javascript/JQuery question that is directly related to the ArcGIS Javascript API... I have a map div created using a 'data' tag in HTML, which becomes visible on a button click. (I'll ...
0
votes
1answer
166 views

Is there a way to control label density in mapserver?

I'm reading a US County Tiger Shapefile and everything is plotting correctly, but I want to slim down the number of labels shown at scales larger than the state level because it begins to overwhelm ...
3
votes
2answers
889 views

Where to download 10m (1/3 arc-second) DEMs?

I'm looking for some of the 10m DEM to fill in the white Quad areas. Do you know where of can I find them? These 10 DEMs we have are actually coming from the NRCS Geospatial Dataway. I believe they ...
2
votes
1answer
51 views

Importing labels for check in/out from an SDE to file geodatabase

I am working on a large project where I am using the ArcMap 10 'distributed geodatabase' feature to check out a file geodatabase from our SDE file. I have tried several ways to avoid having to ...
0
votes
2answers
3k views

How to convert Shapefiles to 3D DXF?

I'm using QGIS version 1.8.0-Lisboa and I'm trying to convert a vector line file and it's not working. I right click on the layer>Save as>Autocad file>DXF. After that I try to open the output file in ...
2
votes
2answers
163 views

How to create `Workspace` without using `IWorkspaceFactory.Create`?

Can I create a Workspace without using IWorkspaceFactory.Create I am trying to create a Workspace without specifying it's parent directory, is that possible ?
0
votes
1answer
456 views

gdaladdo positive and negative aspects?

I read and I read opinions and topics regarding this tool but I am still unclear if I should us this or not. In my project I have thousands off tiff files which need to be put on a map. The problem ...
0
votes
1answer
279 views

Finding route contains Source and Destination points

I have a problem with finding routes that are near (in range X km) the passed points (for e.x. A and B) in PostgreSQL PostGIS. Example: The point A denotes Source point and The point B denotes the ...
0
votes
1answer
164 views

problems about setting pgrouting with QGIS under windows

I followed this website:A Beginner’s Guide to pgRouting and now facing some problems. I finished steps before "Creating a routable road network", and open QGIS 1.8, click the PostGIS Manager plugin, ...
2
votes
1answer
1k views

How to split line layer at polygons' boundary of a polygon layer?

I have a line layer and a polygon layer in PostgreSQL 9.2, PostGIS 2.0. How can I split every line each time it crosses a polygon's boundary?
0
votes
0answers
59 views

Problem with compilation

I have tried to compile Quantum GIS by it's source code on Windows 7 (32 bit).i have follow it's installation guide.i have download and install all it's dependencies . i have run it on C-Make but it ...
0
votes
1answer
154 views

How do I get the closest distance for each element within a point coordinate table from a polyline table?

Postgres: How do I get the closest distance for each element within a point coordinate table from a polyline table? And if this is possible what version of Postgres is this doable.
2
votes
2answers
226 views

How to create a line from more than two points?

I have a loop which calculates two points for each iteration (x3,y3) and (x4,y4). As seen in the code these two points are added for each iteration, which gives i-1 lines. Each line has a individual ...
1
vote
0answers
488 views

Extracting street segments from google maps?

I'm using the google maps v3 api and am trying to extract a list of intersections and street segments from an overlay created from a KML file. Ideally, I'd like to be able to get the poly lines in a ...
2
votes
2answers
4k views

What Spatial Reference System do I store Google Map's Lat/Lng in

I am new to PostGIS, Spatial Reference Systems and projections and want to store lat/lng coordinates retrieved from Google Maps and Openstreetmap and its services like the Geocoder/Nominatim. I'm ...
0
votes
1answer
501 views

What Spatial Reference System do I store Google Map's Lat/Lng in [duplicate]

I am new to PostGIS, Spatial Reference Systems and projections and want to store lat/lng coordinates retrieved from Google Maps and its services like the Geocoder. I'm working with data in America and ...
7
votes
2answers
3k views

Seamless, color balanced mosaics of aerial RGB photos with Open Source

I'm looking for an open source tool/workflow (even a command line one) to obtain what it is advertised in programs like http://www.inpho.de/index.php?seite=index_orthovista http://www.orthomapper....
1
vote
1answer
3k views

How do I create a basic image layer as a base layer in OpenLayers?

I'm trying to create a map using OpenLayers which uses a png image as a base layer but I'm having a bit of trouble. I'm not too familiar with OpenLayers as I have only come across it today and thought ...
1
vote
2answers
95 views

How to partition a Census block shapefile according to towns in a separate shapefile?

I have a census block shapefile and I want to separate the data according to their towns or village. The towns/village is a separate shapefile. Any help is greatly appreciated. I am using ArcInfo ...
5
votes
3answers
7k views

How do I add my own map layers to Leaflet

I have a Leaflet map and want to add two of my own small polygon layers (currently in shapefile format, but they could be converted to GeoJSON). Can this be done without a mapserver to publish them ...
1
vote
2answers
125 views

Where can I get public transportation locations for USA

I am trying to find a list of all public transportation/transit locations like subway stations, airports, bus terminals and bus stops for USA. Only major transit locations are required, rural bus ...
3
votes
2answers
741 views

Flow modeling and FOSS GIS; lahars and HEC-RAS

What are the options for FOSS flow modeling of dilute debris flows in QGIS or GRASS? Have you, or can you refer me to studies where the authors, tested these models/plugins/functions/etc. for use in ...
1
vote
0answers
1k views

How to calculate weighted mean coordinates within polygons?

I'm using QGIS 1.8 on OSX 10.8.3. I have a polygon shapefile of all of the US state legislative districts. I also have a layer of points that are centroids of US Census Tracts, with a field for the ...
1
vote
1answer
1k views

Multiple reclassification using RasterCalc in QGIS [duplicate]

Is there any way to perform multiple reclassification using RasterCalc? For example reclassifying value 1 to 100 in map Map can be written as: eq([Map]@1, 1, 100) But if there are multiple values ...
1
vote
2answers
1k views

How to clip raster by multiple polygons in multi rasters?

Using QGIS, I want to clip a raster by multiple polygons contained in a single shapefile. I read that gdalwarp can clip my raster by multiple polygons BUT the output is a single merged clipped raster. ...
2
votes
0answers
216 views

How can I improve my Ray casting algorithm?

I have been using the following function below which have been working well to decide if a point in the polygon but once I have many points which is building the polygon say over few thousand it seems ...
5
votes
2answers
1k views

How to perform SIA or Bezier line smoothing in PostGIS?

Can anyone provide an example SQL for smoothing linestrings from postgis table using Bezier curves or Iterative Averaging (SIA) algorithm?
3
votes
1answer
3k views

WGS84 - how to convert

I have multiple locations saved in WGS84 - it looks like e.g. latitude: 12345678 longitude: 87654321. I tried to search it on the map this way: 12.345678 87.654321, but it doesn't match the place it ...
6
votes
2answers
1k views

Is there a way to call the clip function in pyQGIS from the python console?

Is there a way to call the clip function in QQGIS from the python console? It is found under geoprocessing tools in the vector menu.
1
vote
1answer
117 views

Diff operation in PostGIS/Geotools

What is the best way to perform a diff operation on Postgis features/tables or Geotools objects? Are there any automatic methods I can use? If not, what would be the optimal way to implement your own ...
3
votes
0answers
43 views

Clustering driven by an enum/list

Given a set of 2D points ( or vertices if you want ), the values stored for each point are: coordinate on x coordinate on y an enum or a value from a list in general for the sake of this example ...
0
votes
1answer
1k views

how to configure WFS layer with openlayer in PHP wampserver with windows?

I have a problem to display WFS layer outside the Geoserver. My code working fine in geoserver, but when I tried my code in wampserver(PHP), only WMS layer is being to displayed. I gone through many ...
6
votes
2answers
2k views

Leaflet offline tiles problem

I hate to ask this kind of questions, but i ve been stuck for 2 days now: I rendered some tiles with mapnik which i want to serve in my offline application which will run from a portable disk, but ...
3
votes
2answers
3k views

How to add a column in QGIS via python

I have a point shapefile and a polygon shapefile in QGIS now I want to use the point shapefile's value add to polygon shapfile(be a column in the end) there are colors with each value and make the ...
2
votes
2answers
953 views

Using GIS in Civil Engineering construction field? [closed]

I am thinking "How to use GIS when construction HighWays,Buildings,pipe lines etc?" Is there any way we can utilize GIS for Civil Engineering construction industry to increase the efficiency of ...
11
votes
1answer
693 views

Teaching Python to Land Surveyors

Does anyone have any good examples of using Python to automate or simplify common surveying tasks? I'm teaching a Python/ArcPy lab this week for a GIS class. There are a number of surveying ...
2
votes
1answer
542 views

Using Openlayers for GeoRSS from remote website

I am trying to get features from remote GeoRSS file with Openlayers... But I am stuck. Openlayers can not read remote file. I have searched on the net but I could not find any solution... Here is the ...
1
vote
1answer
963 views

ST_Box2D in PostGIS 2.0

I am getting an error trying to create a bounding box of a geometry using ST_Box2D(). Is the function deprecated? If so, what is the equivalent function? SELECT ST_Box2D(ST_GeomFromText('LINESTRING(1 ...
1
vote
0answers
200 views

When should I merge two or more sub-basins into one?

I've been using Archydro to analyze one of the unknown hilly regions with many watersheds. Unfortunately, ArcHydro generates so many sub-basins that it looks really unrealistic and weird. However, I ...
3
votes
0answers
99 views

Looking for examples on how GIS techniques facilitate utility surveying and management [closed]

Anyone get some ideas about the interface between underground utility and GIS? Utility surveying is quite a new topic to me and I want some examples on how GIS techniques facilitate utility surveying ...
0
votes
2answers
154 views

Some highways segments ignored by osm2po?

Where i can read why some roads/segments are disappear from routing? We are trying to comment all "wtr.deny" rules in config file, but nothing changed. Examples added as links bellow. Screenshot1 ...

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