4,156 reputation
732
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location Hamilton, Canada
age 35
visits member for 2 years, 4 months
seen 21 hours ago

Jul
22
comment How likely is it that Smartphone Camera GPS coordinates are wrong?
I am sure there is a way to change the data on the EXIF, but it is very unlikely.
Jul
22
comment Setting the Geometry with sql query
Without looking at the data it is a little difficult for me, but you could look at table joins or spatial joins. I am assuming you have some data with birth rates (points or polygons). If the birth rates data has any attributes related to the state, then you could do a table join with the state polygon to put that data into the state table. Otherwise, you may want to do a spatial join. Going about this will depend on how your data is put together.
Jul
22
comment Setting the Geometry with sql query
What software are you using to do this. A shapefile is not a database, and the query you are using is specific to a spatial database (ie: Spatialite, PostGIS, etc.). If you want to do those types of queries you will want to put your data into a spatial database (like the types mentioned above).
Jul
18
comment Image classification using google satellite images
You could do that, but be careful about having hard and fast rules. One of the issues with classification is that it uses real world imagery; and real world imagery has variation. Setting a RGB value may result in different classes depending on the temporal and spatial location of the image. If you will be using a repetitive location (ie: time series analysis) then you may be ok. But if you are not, or you will be looking at temporal change, then you will have to deal with a feature having different pixel values at different times of the year (ie: trees). Also don't forget about clouds, etc.
Jul
18
comment Image classification using google satellite images
That will depend on what you are using to classify. If I assume correctly, you are making your own? You will want to look at the pixel values of each band. But you may want to do a neighbour search (3x3, 5x5, 7x7, etc.). Object oriented classification looks at the direction, orientation, proximity, and other aspects of pixels.
Jul
14
comment Is it possible to embed a Qgis map with all the information I added, in my website?
Look at CartoDB. I have a free account with them. You are limited to the number of layers you can show on the free web map. cartodb.com/signup Signup and you will default to the free account
Jul
14
comment Is it possible to embed a Qgis map with all the information I added, in my website?
You will be able to use QGIS to make some of the data. I have used MapBox and CartoDB to do this very thing. I found that GeoJSON is the best data format for web maps such as MapBox and CartoDB.
Jun
24
comment Using the Rule-based style to calculate each grid cell from overlaps
No problem Joseph. What I do in cases like yours is to add a filter for each option (ie: CASE). So if you have 4 options you are looking at, then you would want to add 4 different filters. Each filter could have a multiple attribute query. I have added a graphic showing what I mean.
Jun
19
comment Is there a way to use gdal functions from OSGeo4W out of their shell?
Then I am not sure what you mean. If you can access gdal commands from OSGeo4W then what is the issue? Do you want to bundle things from your ESRI python? That may not be possible, but I will let someone else tackle it. I have python scripts that call gdal. What I have done is to evoke it from a commandline tool, but I have to type python first, then the python script file (ie: python c:\temp\cool_script.py) If you want to use an ESRI script and a gdal script for processing, you may have to batch that. Create a bat file that calls the scripts in order, or even a python script to do that
Jun
19
comment Is there a way to use gdal functions from OSGeo4W out of their shell?
So for example, in OSGeo4W if you type gdal_merge nothing comes up? You should see something like this: Usage: gdal_merge.py [-o out_filename] [-of out_format] [-co NAME=VALUE]* [-ps pixelsize_x pixelsize_y] [-tap] [-separate] [-q] [-v] [-pct] [-ul_lr ulx uly lrx lry] [-init "value [value...]"] [-n nodata_value] [-a_nodata output_nodata_value] [-ot datatype] [-createonly] input_files [--help-general]
Jun
16
comment PostGIS Group By Error
Sorry Paul, I didn't know you were filling something in. If you want to add the answer back up, I am sure others would find it useful. I do understand the meaning of GROUP BY; this example doesn't properly show my example. But thank you for your help.
Jun
16
comment PostGIS Group By Error
Thanks, that worked. Do you have any idea why it would need a uid / gid? I haven't needed to do this with other databases.
Jun
16
comment PostGIS Group By Error
When I perform a similar query in Spatialite I do not see this issue. What I am looking for is all the city names that have a city_abbr of nyc. I want to make sure I only get one return if there are cities that share the same city name. I understand distinct will give me this result, but I don't understand why GROUP BY needs to have all the columns that are identified in the SELECT.
Jun
9
comment Z values all equal 0
Thats unfortunate. I have never tried this, but you could look at doing Zonal Statistics to Table, which is in Toolbox --> Spatial Analyst. I have successfully used it with polygons, but not points. If this does not work for a point file, you could buffer the points to a small distance (ie: 0.05m) and then run the process on the buffered points.
Jun
6
comment How to add polygon height in QGIS or PostGIS?
Then I would suggest that you state that a little more clearly in your comments. Also, the title of the question should better reflect the question that is being asked.
Jun
6
comment How to select zip codes without using the lasso tool
A spatial join will intersect the zip code polygons, and put the attribute of the zip code in the point layer attribute table. With the attributes in the point layer, you can then perform SQL queries as needed, without any manual selections.
Jun
6
comment How to add polygon height in QGIS or PostGIS?
Technically no it doesn't, you are not viewing it in QGIS. QGIS provided the means to prep the data for viewing in a different viewing software, such as exporting a KML for viewing in Google Earth. However, in this case, you will want to have an attribute that has a height value, which will be used to extrude. This process is referred to as 2.5D, as it does not have 3D geometries.
May
28
comment How to extract Z data from a point layer
I have never had an issue with this process. An alternative is to use GME (Geospatial Modeling Environment) spatialecology.com/gme and use the isectpntrst tool
May
28
comment How to create a TIN from UAV images or Google Earth images
No, the joining of images will only give you a mosaic (single image for visual...pretty picture). You need to have a software (PhotoSynth or SimActive) that can make a point cloud from multiple images). I suggest you continue looking online at options. There are some pages dedicated to this process. I have seen someone put up a full workflow using a SenseFly UAV.
May
28
comment How to use Google Maps projection with GeoDjango/PostGIS
Well that is no the purpose of the website. It was created as a reference, not a tool to answer specific questions related to technology or software products.