Can someone help me to find a repository of ArcGIS-ready shapefiles for Brazil?
I am a human geographer working on my first GIS project. Can someone help me to find a repository of ArcGIS-ready shapefiles for Brazil? I especially need oceanographic data such as depths, salinity, mean temperatures, bottom conditions, etc. The specific area in which I am
working is the Bahia de Todos os Santos (by Salvador, in Bahia state). Free data is of coursebetter but I am not against paying for good useful data.
Muito obrigado! Many thanks!
Mapping Center Answer:
My experience is that such data just doesn't exist, particularly in terms of GIS-ready (never mind ArcGIS). There are a number of organizations, NOAA included, that collect many of the datasets you mention, but do so for a global scale and you can extract what you'd need from those datasets. We did a project here a few years ago, making a Bucky Fuller globe with different thematic information for each facet—we all got quite familiar with sources for oceanographic data at the time. We found what we needed by Googling. In my case I found quite a bit at a University of Maryland site where a group of professors had a grant to collect the data—they made it public, and were kind enough to answer my questions about the data.
For generic base maps, the ESRI Maps and Data CDs have decent mid-scale data for all areas of the world; if you need detailed data, you'll likely need to contact the Brazilian state or national mapping folks and see what they can help with. Most such groups are pretty good about helping researchers, in terms of not charging for than the effort, media, and postage.
Back to the GIS-ready issue. Much of the data is in tabular format with X & Y coordinates. ArcGIS has a feature called XY Events (tools menu in ArcMap) that will display such data. I typically export the XY Event layer to a shapefile or geodatabase feature class immediately, which allows me to then to add or remove fields as I need. Learning to use the Field Calculator is a life-skill with this sort of data. Using the Spatial Analyst interpolation tools is also something I would expect you will need to do; this will allow you to create thematic surfaces of the XY Data, and then perform analyses on those surfaces.
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