Geographic Information Systems Weekly Newsletter
Geographic Information Systems Weekly Newsletter

Top new questions this week:

Raster diff: how to check if images have identical values?

Is there a means to check to see if any 2 given raster layers have identical content? We have a problem on our corporate shared storage volume: it's now so big that it takes over 3 days to conduct a …

python raster compression differences  
asked by matt wilkie 9 votes
answered by Aaron 5 votes

Does dissolving features improve geoprocessing efficiency?

I have a large set of line data (>140,000 features). Is there a processing advantage, in either time required or (more importantly) memory used: to running Dissolve on the data before running …

arcgis-desktop arcpy arcgis-10.2 geoprocessing dissolve  
asked by Erica 6 votes
answered by Vince 6 votes

How to create a storm swath map?

I can't really find the words to explain what I'd like to achieve so I attached a picture. The top picture was made of two layers, the layer with circles was made/styled using the instructions from …

asked by euler 6 votes
answered by Alexandre Neto 9 votes

How do ESRI and QGIS calculate scale values of geographic projections?

Does anyone know how (from which location) scale values are calculated in ESRI products and QGIS for geographic projections? The only thing I've noticed is that QGIS is changing scales when you pan …

qgis arcgis-desktop projection scale  
asked by Karol Kolenda 4 votes

Is it possible to calculate statistics across multiple fields in arcpy?

The summary statistics command can be used in arcpy to calculate statistics - this tool runs against a single field, eg: SUM—Adds the total value for the specified field. Is there an …

arcpy statistics  
asked by Stephen Lead 4 votes
answered by PolyGeo 2 votes

The scale in Qgis is not setting to feet

I am working in QGIS 2.4. I have changed the CRS of all the layers and in the project properties to EPSG:102739 - NAD_1983_StatePlane_Texas_Central_FIPS_4203_Feet. I am in print composer trying to …

qgis scale composer scalebar  
asked by Tatiana Perry 4 votes
answered by underdark 2 votes

Making 'persistent' ArcMap tool without creating Python add-in?

I want to make an addon that, while editing in ArcMap, will track where I pan and move the viewport. I have the pieces together, but I don't like debugging with the Python Add-In wizard, because I …

arcgis-desktop arcgis-10.2 geoprocessing arctoolbox python-addin  
asked by Barrett 4 votes
answered by Hornbydd 0 votes

Greatest hits from previous weeks:

Layers with same coordinate system should align/overlap but do not?

I put 4 different layers into my ArcMap document, but only one of them will show up on the map! I should be seeing the other 3 layers as well. When I do a Zoom to layer, I can see one layer, but I …

arcgis-desktop arcgis-10.0 projection coordinate-system projection-conversions  
asked by CaliforniaGirl 20 votes
answered by Get Spatial 30 votes

How to merge multiple layers to one layer using QGIS?

I've imported several shapefiles which where exported from an Mapinfo .tab. Several tab files are imported resulting in 20+ layers. Afterwards I want to export it to geoJSON; but I'm reluctant for …

asked by stUrb 15 votes
answered by Aragon 19 votes

Can you answer these?

OpenLayers.Renderer.Symbols custom named by function

Is there any approach to define custom OpenLayers.Renderer.symbol by a function? For example, instead of making a symbol for each 3-pointed, 4-pointed, 5-pointed etc. star …

openlayers rendering symbol  
asked by user32916 2 votes

Convert las files to ASCII raster format with the same cell size?

I am following the steps in this blog, but I cannot complete the Grid Difference step because my DSM and DEM have different grid systems. I have las files with almost the same area extent, but when …

raster lidar resolution esri-ascii-raster global-mapper  
asked by Zia 2 votes

QGIS WEB Cliente para windows 7

Bom dia, estou com alguma dúvidas a respeito do QGIS WEB Cliente que não consigo achar uma solução. Eu sei que tenho que fazer a instalação do Qgis Serve como esta escrito neste tutorial Anita Graser …

asked by Manoel Guedes 2 votes
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